From pgsql-hackers-owner+M174@hub.org Sun Mar 12 22:31:11 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA25886 for ; Sun, 12 Mar 2000 23:31:10 -0500 (EST) Received: from news.tht.net (news.hub.org [216.126.91.242]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id XAA04589 for ; Sun, 12 Mar 2000 23:19:33 -0500 (EST) Received: from hub.org (hub.org [216.126.84.1]) by news.tht.net (8.9.3/8.9.3) with SMTP id XAA42854; Sun, 12 Mar 2000 23:05:05 -0500 (EST) (envelope-from pgsql-hackers-owner+M174@hub.org) Received: from candle.pha.pa.us (root@s5-03.ppp.op.net [209.152.195.67]) by hub.org (8.9.3/8.9.3) with ESMTP id XAA95917 for ; Sun, 12 Mar 2000 23:00:56 -0500 (EST) (envelope-from pgman@candle.pha.pa.us) Received: (from pgman@localhost) by candle.pha.pa.us (8.9.0/8.9.0) id WAA25403 for pgsql-hackers@postgreSQL.org; Sun, 12 Mar 2000 22:59:56 -0500 (EST) From: Bruce Momjian Message-Id: <200003130359.WAA25403@candle.pha.pa.us> Subject: [HACKERS] Fix for RENAME To: PostgreSQL-development Date: Sun, 12 Mar 2000 22:59:56 -0500 (EST) X-Mailer: ELM [version 2.4ME+ PL72 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO I have thought about the issue with ALTER TABLE RENAME and keeping the file system in sync with the database. It seems there are three commands that can cause these to get out of sync: CREATE TABLE/INDEX DROP TABLE/INDEX ALTER TABLE RENAME Now, if we had file names based only on the oid, we can eliminate file renaming for RENAME, but the others are still a problem. Seems there are three ways to get out of sync: ABORT transaction backend crash OS crash The last two are the same, except the backend crash restarts the postmaster, while the OS crash has the postmaster starting up normally. Here is my idea. Create a C List of file names to unlink on transaction commit or abort. For CREATE, unlink created files on transaction ABORT. For DROP, unlink dropped files on COMMIT. For RENAME, create a hard link for the new table linked to old table, and unlink the old file name on COMMIT or the new file on ABORT. That takes care of COMMIT and ABORT. For backend crash or OS crash, add a postgres command-line flag for recovery. Have the postmaster on startup or shared memory refresh start up a postgres backend on every database with the recovery flag set. Have the postgres backend find all the oids in the pg_class table, and have it go through every file in the database directory and remove all files that don't match the oids/names in pg_class. Also, remove all old sort, noname, and temp files at the same time. Seems we should be doing this anyway. Care would have to be taken that a corrupted database that caused a postgres crash on connection would not get the postmaster startup into an infinite loop. Comments? -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 From reedstrm@wallace.ece.rice.edu Tue Mar 14 12:33:31 2000 Received: from wallace.ece.rice.edu (root@wallace.ece.rice.edu [128.42.12.154]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA23826 for ; Tue, 14 Mar 2000 13:33:29 -0500 (EST) Received: by wallace.ece.rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for pgman@candle.pha.pa.us; Tue, 14 Mar 2000 12:33:32 -0600 (CST) Date: Tue, 14 Mar 2000 12:33:32 -0600 From: "Ross J. Reedstrom" To: Hiroshi Inoue Cc: Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Fix for RENAME Message-ID: <20000314123331.A6094@rice.edu> References: <200003140317.WAA27733@candle.pha.pa.us> <000c01bf8d75$a0016800$2801007e@tpf.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii User-Agent: Mutt/1.0i In-Reply-To: <000c01bf8d75$a0016800$2801007e@tpf.co.jp>; from Inoue@tpf.co.jp on Tue, Mar 14, 2000 at 02:24:52PM +0900 Status: RO Hiroshi - I've just about finished working up a patch to store the physical file name in the pg_class table. There are only two places that require a Rule for generating the filename, and one of them is only used for bootstrapping. For the initial cut, I used the rule: The filename consists of the TABLENAME, and underscore, and the OID. If this is longer than NAMEDATALEN, shorten the TABLENAME. I implemented this rule by exporting Tom's makeObjectName function from analyze.c, which is used to make other system generated names that are have a requirement to be human readable. Replacing this rule with any other in the future would be straightforward, except for bootstrap. There are a number of places in bootstrap that need to know the filename. I've factored them out into yet another set of #defines (in catname.h) to make that easier. I'm working through the regression tests right now: this is a relatively extensive change, since it modifies the low level access routines, and the buffer cache (which I indexed on physical filename, rather than relname, as it is now) Hopefully, I caught all the places that assume relname == filename == unique name within a single database (see, I want schemas...) Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 On Tue, Mar 14, 2000 at 02:24:52PM +0900, Hiroshi Inoue wrote: > > -----Original Message----- > > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > > > > They use the existing table file. It is only when > > > > adding/removing/renaming file system files that this > > out-of-sync problem > > > > happens. > > > > > > > > Not sure. I was going to get the CREATE/DROP/RENAME working as it > > should then as we add more features, we can implement this solution for > > them too. > > > > Hmm,is general solution difficult ? > Is more flexible naming rule bad ? > > This the 3rd or 4th time that I mention the following. > > PostgreSQL doesn't keep the information in itself where tables are > allocated. So we need a naming rule to find where existent tables > are allocated. Don't you wonder the spec ? > > Regards. > > Hiroshi Inoue > Inoue@tpf.co.jp > > From pgsql-hackers-owner+M74@hub.org Tue Mar 14 18:14:15 2000 Received: from hub.org (hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA06093 for ; Tue, 14 Mar 2000 19:14:13 -0500 (EST) Received: from hub.org (hub.org [216.126.84.1]) by hub.org (8.9.3/8.9.3) with SMTP id SAA95465; Tue, 14 Mar 2000 18:45:35 -0500 (EST) (envelope-from pgsql-hackers-owner+M74@hub.org) Received: from wallace.ece.rice.edu (root@wallace.ece.rice.edu [128.42.12.154]) by hub.org (8.9.3/8.9.3) with ESMTP id NAA31276 for ; Tue, 14 Mar 2000 13:33:52 -0500 (EST) (envelope-from reedstrm@wallace.ece.rice.edu) Received: by wallace.ece.rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for pgsql-hackers@postgresql.org; Tue, 14 Mar 2000 12:33:32 -0600 (CST) Date: Tue, 14 Mar 2000 12:33:32 -0600 From: "Ross J. Reedstrom" To: Hiroshi Inoue Cc: Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Fix for RENAME Message-ID: <20000314123331.A6094@rice.edu> References: <200003140317.WAA27733@candle.pha.pa.us> <000c01bf8d75$a0016800$2801007e@tpf.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii User-Agent: Mutt/1.0i In-Reply-To: <000c01bf8d75$a0016800$2801007e@tpf.co.jp>; from Inoue@tpf.co.jp on Tue, Mar 14, 2000 at 02:24:52PM +0900 Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Hiroshi - I've just about finished working up a patch to store the physical file name in the pg_class table. There are only two places that require a Rule for generating the filename, and one of them is only used for bootstrapping. For the initial cut, I used the rule: The filename consists of the TABLENAME, and underscore, and the OID. If this is longer than NAMEDATALEN, shorten the TABLENAME. I implemented this rule by exporting Tom's makeObjectName function from analyze.c, which is used to make other system generated names that are have a requirement to be human readable. Replacing this rule with any other in the future would be straightforward, except for bootstrap. There are a number of places in bootstrap that need to know the filename. I've factored them out into yet another set of #defines (in catname.h) to make that easier. I'm working through the regression tests right now: this is a relatively extensive change, since it modifies the low level access routines, and the buffer cache (which I indexed on physical filename, rather than relname, as it is now) Hopefully, I caught all the places that assume relname == filename == unique name within a single database (see, I want schemas...) Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 On Tue, Mar 14, 2000 at 02:24:52PM +0900, Hiroshi Inoue wrote: > > -----Original Message----- > > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > > > > They use the existing table file. It is only when > > > > adding/removing/renaming file system files that this > > out-of-sync problem > > > > happens. > > > > > > > > Not sure. I was going to get the CREATE/DROP/RENAME working as it > > should then as we add more features, we can implement this solution for > > them too. > > > > Hmm,is general solution difficult ? > Is more flexible naming rule bad ? > > This the 3rd or 4th time that I mention the following. > > PostgreSQL doesn't keep the information in itself where tables are > allocated. So we need a naming rule to find where existent tables > are allocated. Don't you wonder the spec ? > > Regards. > > Hiroshi Inoue > Inoue@tpf.co.jp > > From mascarm@mascari.com Tue Mar 14 16:34:04 2000 Received: from corvette.mascari.com (dhcp26136016.columbus.rr.com [24.26.136.16]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA04395 for ; Tue, 14 Mar 2000 17:32:14 -0500 (EST) Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id RAA09562; Tue, 14 Mar 2000 17:27:22 -0500 Message-ID: <38CEBD0A.52ADB37E@mascari.com> Date: Tue, 14 Mar 2000 17:28:26 -0500 From: Mike Mascari X-Mailer: Mozilla 4.7 [en] (Win95; I) X-Accept-Language: en MIME-Version: 1.0 To: Bruce Momjian CC: Hiroshi Inoue , PostgreSQL-development Subject: Re: [HACKERS] Fix for RENAME References: <200003141545.KAA17518@candle.pha.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: RO Bruce Momjian wrote: > > > Hmm,is general solution difficult ? > > Is more flexible naming rule bad ? > > > > This the 3rd or 4th time that I mention the following. > > That's because I didn't understand. > > > > > PostgreSQL doesn't keep the information in itself where tables are > > allocated. So we need a naming rule to find where existent tables > > are allocated. Don't you wonder the spec ? > > How does naming the files in the database help our DROP/CREATE problem? > It would help RENAME a little bit. Not sure about the others because > currently they don't have a problem. I've been thinking about this somewhat, and I think the first step necessary in correctly supporting ROLLBACK-able DDL statements in transactions is the change to _. Imagine the scenario: CREATE TABLE test (key int4); a) Session #1: BEGIN; b) Session #2: BEGIN; DROP TABLE test; CREATE TABLE test (value varchar(32)); c) Session #1: DROP TABLE test; COMMIT; d) Session #2: COMMIT; What's clear to me is that, if DDL statements are to be ROLLBACK-able, either (1) an AccessExclusive lock is held on the relation until transaction commit (like Phillip Warner stated was Dec/Rdb's behavior) or (2) PostgreSQL must be capable of supporting "multi-versioned schema" as well as tuples. Before step 'c' is executed, both tables must simultaneously exist in the database with the same name, which works fine in the cataloge thanks to MVCC, but requires that, on disk, there exists: test_01231 - Session #1's table, available for ROLLBACK test_13421 - Session #2's table, available for COMMIT Now, I believe it was Andreas who suggested that VACUUM be modified to perform cleanup. I agree with this. VACUUM will need to check for aborted relation tuples in pg_class and remove the associated file from the filesystem in the event, for example, that Session #2 aborted -or- Session #1 aborted leaving the original pg_class tuple the "active" one and Session #2 attempted to COMMIT, which violates the UNIQUE constraint on the relname of pg_class. In addition, for "active" relation entries, VACUUM should verify the filename is _ for the given oid. If it is not, it should rename the filename on the filesystem. Again, this is purely cosmetic for administrative purposes only, but would allow for lack of atomicity only with respect to the label of the relation file, until the next VACUUM is run. For the case of ALTER TABLE RENAME, ALTER TABLE DROP COLUMN, etc., the same functionality would apply. But, as in previous discussions regarding ALTER TABLE DROP COLUMN, PostgreSQL MUST be capable of allowing multiple tuples with different attribute counts and types within the same relation: CREATE TABLE test (key int4); a) Session #1: BEGIN; b) Session #2: BEGIN; ALTER TABLE test ADD COLUMN value int4; INSERT INTO test values (1, 1); c) Session #1: INSERT INTO test values (0); COMMIT; d) Session #2: COMMIT; This also means that Hiroshi's plan to suppress the visibility of attributes for ALTER TABLE DROP COLUMN would be required anyway, to allow for "multi-versioning" of attributes within a single tuple (i.e., like multi-versioning of tuples within relations), an attribute is either visible or not, but the tuple should always grow, until, of course, the next VACUUM. So, to support rollback-able DDL statements ("multi-versioning schema", if you will), PostgreSQL needs: 1) relation names of the form _ 2) support "multi-versioning" of attributes within a single tuple 3) modify VACUUM to: A) Remove filesystem files whose pg_class tuples are no longer valid B) Rename filesystem files to relname of pg_class when the _ doesn't match C) Reconstruct relations after attributes have been added/dropped. 4) All DDL statements should perform their non-create filesystem functions in the now infamous "post-transaction-commit" trigger. If the backend should crash between the time the transaction committed and the rename() or unlink(), no adverse affects would be encountered with the database WRT data, VACUUM would clean up the rename() problem, and, worst-case scenario, an old _ file would lie around unused. But at least it would no longer prohibit the creation of a table by the same name.... Just my humble opinion, Mike Mascari From Inoue@tpf.co.jp Tue Mar 14 20:31:35 2000 Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA08792 for ; Tue, 14 Mar 2000 21:30:35 -0500 (EST) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id LAA00515; Wed, 15 Mar 2000 11:29:09 +0900 From: "Hiroshi Inoue" To: "Ross J. Reedstrom" , "Bruce Momjian" Cc: "PostgreSQL-development" Subject: RE: [HACKERS] Fix for RENAME Date: Wed, 15 Mar 2000 11:35:46 +0900 Message-ID: <000c01bf8e27$2b3c3ce0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 In-Reply-To: <20000314123331.A6094@rice.edu> Importance: Normal Status: ROr > -----Original Message----- > From: Ross J. Reedstrom [mailto:reedstrm@wallace.ece.rice.edu] > > Hiroshi - > I've just about finished working up a patch to store the physical > file name in the pg_class table. There are only two places that > require a Rule for generating the filename, and one of them is > only used for bootstrapping. Thanks for your trial. It's nice that only two places require naming rule. I don't stick to one naming rule. The only limitation is the uniqueness and the rule could be changed according to situations. For example,we could change the naming rule according to the kind of relation such as system/user relations. I'm now inclined to introduce a new system relation to store the physical path name. It could also have table(data)space information in the (near ?) future. It seems better to separate it from pg_class because table(data?) space may change the concept of table allocation. Comments ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Wed Mar 15 02:00:58 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA17887 for ; Wed, 15 Mar 2000 03:00:57 -0500 (EST) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id CAA02974 for ; Wed, 15 Mar 2000 02:54:44 -0500 (EST) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id QAA00734; Wed, 15 Mar 2000 16:53:56 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" Cc: "Ross J. Reedstrom" , "PostgreSQL-development" Subject: RE: [HACKERS] Fix for RENAME Date: Wed, 15 Mar 2000 17:00:35 +0900 Message-ID: <001101bf8e54$8b941cc0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 In-Reply-To: <200003150433.XAA13256@candle.pha.pa.us> Importance: Normal Status: ROr > -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > I'm now inclined to introduce a new system relation to store > > the physical path name. It could also have table(data)space > > information in the (near ?) future. > > It seems better to separate it from pg_class because table(data?) > > space may change the concept of table allocation. > > Why not just put it in pg_class? > Not sure,it's only my feeling. Comments please,everyone. We have taken a practical way which doesn't break file per table assumption in this thread and it wouldn't so difficult to implement. In fact Ross has already tried it. However there was a discussion about data(table)space for months ago and currently a new discussion is there. Judging from the previous discussion,I can't expect so much that it could get a practical consensus(How many opinions there were). We can make a practical step toward future by encapsulating the information of table allocation. Separating table alloc info from pg_class seems one of the way. There may be more essential things for encapsulation. Comments ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M196@hub.org Thu Mar 16 03:02:35 2000 Received: from hub.org (hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA05789 for ; Thu, 16 Mar 2000 04:02:29 -0500 (EST) Received: from hub.org (hub.org [216.126.84.1]) by hub.org (8.9.3/8.9.3) with SMTP id CAA27302; Thu, 16 Mar 2000 02:58:55 -0500 (EST) (envelope-from pgsql-hackers-owner+M196@hub.org) Received: from downtown.oche.de (root@downtown.oche.de [194.94.253.3]) by hub.org (8.9.3/8.9.3) with ESMTP id CAA23907 for ; Thu, 16 Mar 2000 02:37:54 -0500 (EST) (envelope-from mne@darwin.oche.de) Received: from darwin.oche.de (uucp@localhost) by downtown.oche.de (8.9.3/8.9.3/Debian/GNU) with SMTP id IAA30654 for ; Thu, 16 Mar 2000 08:40:04 +0100 Received: from mne by darwin.oche.de with local (Exim 3.12 #1 (Debian)) id 12VUhX-0003Vz-00 for ; Thu, 16 Mar 2000 08:28:11 +0100 Date: Thu, 16 Mar 2000 08:28:11 +0100 (CET) From: Martin Neumann Subject: [HACKERS] RfD: Design of tablespaces To: pgsql-hackers@postgresql.org MIME-Version: 1.0 Content-Type: TEXT/plain; CHARSET=US-ASCII Message-Id: Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO I have written some thoughts on the concept of tablespace down. I would be happy to get some comments on it. ----------------------------------------------------------------- Implementation of tablespaces within PostgreSQL - a brainstorming paper designed for general discussion - by Martin Neumann, 2000/3/15 1. What are tablespaces? ------------------------- Tablespaces make it possible to distribute storage objects over multiple points of storage (POS). Therefor one could say a tablespace can be a POS. Example: tablespace_a -----> /mnt/raid/arena0/ tablespace_b -----> /mnt/raid/emc0/ Tablespaces can also store their data on other tablespaces: tablespace_c -----> tablespace_b This is quite interessting for administration purposes. 2. What are its advantages? ---------------------------- As you can choose a different tablespace for every storage object (table, index etc.) it is easy to improve the following aspects of your system: - Reliability You can put storage objects (mostly tables) you strongly depend on onto a more reliable tablespace (mirrored RAID or perhaps simply a directory which gets backuped more often than others). - Speed You can put storage objects you rarely need onto a rather slow tablespace and keep your quick tablespaces clean from this. A fast, but more expensive RAID-Stripeset can be used more efficiently as it doesn't get filled with non-performance sensitive data. But also distributing storage objects which have equal needs in sense of speed onto different tablespaces makes sense as you gain more speed by distributing data over more than one harddisk spindle. - Manageability You can grant and revoke rights on base of a tablespace. As every storage object belongs to exactly one tablespace, you can easily group storage objects using a tablespace. 3. What about disk I/O? ------------------------ Tablespaces tell the storage manager only where to store the data, not how. This is the reasonable way. 4. Usage --------- CREATE TABLESPACE tsname TYPE storage_type storage_options Examples: CREATE TABLESPACE tsemc0 TYPE classic DIRECTORY /mnt/raid/emc0 NOFSYNC CREATE TABLESPACE tsarena0 TYPE raw DEVICE /dev/araid/0 MINSIZE 128 MAXSIZE 4096 GROW 4 32 SHRINK 2 32 BLOCKSIZE 16384 CREATE TABLESPACE quick0 TYPE link TABLESPACE tsarena0; -- CREATE TABLE tbname ( ... ) TABLESPACE tsname; Examples: CREATE TABLE foo ( id int4 NOT NULL UNIQUE, name text NOT NULL ) TABLESPACE tsemc0; CREATE TABLE bar ( id int4 NOT NULL UNIQUE, name text NOT NULL ) TABLESPACE default; If the tablespace isn't given, the storage objects gets created in the "default" tablespace. "default" is the PostgreSQL's default tablespace and the only one which has to exist on each system. -- ALTER TABLESPACE tsname tssettings Examples: ALTER TABLESPACE tsemc0 DIRECTORY /mnt/raid/emc1 NOTE: altering tablespaces without recreating the contained storage objects introduces many problems. Realisation is difficult and won't be my first goal. -- DROP TABLESPACE tsname [FORCE] Examples: DROP TABLESPACE tsarena0 This will immediately remove the tablespace tsarena0 if it contains no storage objects. If it still contains some the tablespace is marked for deletion. This means: 1. you can't create new storage objects in the tablespace 2. if the last storage object inside gets dropped, the tablespace will be removed. DROP TABLESPACE tsarena0 FORCE This will remove the tablespace including all contained storage objects immediately. -- VACUUM tsname Example: VACUUM tsemc1 This will vacuum a single tablespace with all contained storage objects. ----------------------------------------------------------------- -- Martin Neumann, Welkenrather Str. 118c, 52074 Aachen, Germany mne@mne.de - http://www.mne.de/mne/ - sms@mne.de [eMail2SMS] Tel. 0241 / 8876-080 - Mobil: 0173 / 27 69 632 ..------.--------------------------------------------------------- | at | Inform GmbH - Abteilung Airport Logistics | work | Pascalstr. 23 - 52076 Aachen - Tel. 02408 / 9456-0 |______| martin.neumann@inform-ac.com - http://www.inform-ac.com From JanWieck@t-online.de Wed Jun 14 19:01:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA21372 for ; Wed, 14 Jun 2000 19:00:59 -0400 (EDT) Received: from mailout02.sul.t-online.com (mailout02.sul.t-online.com [194.25.134.17]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id SAA01930 for ; Wed, 14 Jun 2000 18:51:11 -0400 (EDT) Received: from fwd01.sul.t-online.de by mailout02.sul.t-online.com with smtp id 132Lz6-0004ec-01; Thu, 15 Jun 2000 00:50:08 +0200 Received: from hot.jw.home (340000654369-0001@[62.224.107.172]) by fwd01.sul.t-online.de with esmtp id 132Lyy-0tYyi9C; Thu, 15 Jun 2000 00:50:00 +0200 Received: (from wieck@localhost) by hot.jw.home (8.8.5/8.8.5) id WAA07887; Wed, 14 Jun 2000 22:43:39 +0200 From: JanWieck@t-online.de (Jan Wieck) Message-Id: <200006142043.WAA07887@hot.jw.home> Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <14752.960996980@sss.pgh.pa.us> from Tom Lane at "Jun 14, 2000 11:36:20 am" To: Tom Lane Date: Wed, 14 Jun 2000 22:43:39 +0200 (MEST) CC: Oliver Elphick , Bruce Momjian , PostgreSQL-development Reply-To: Jan Wieck X-Mailer: ELM [version 2.4ME+ PL68 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Sender: 340000654369-0001@t-dialin.net Status: ROr Tom Lane wrote: > "Oliver Elphick" writes: > > I suggest that DROP TABLE in a transaction should not be allowed. > > I had actually made it do that for a short time early this year, > and was shouted down. On reflection I have to agree; it's too useful > to be able to do > > begin; > drop table foo; > create table foo(new schema); > ... > end; > > You do indeed lose big if you suffer an error partway through, but > the answer to that is to fix our file naming conventions so that we > can support rollback of drop table. Belongs IMHO to the discussion to keep separate what is separate (having indices/toast-relations/etc. in separate directories and whatnot). I've never been really happy with the file naming conventions. The need of a filesystem entry to have the same name of the DB object that is associated with it isn't right. I know, some people love to be able to easily identify the files with ls(1). OTOH what is that good for? Well, someone can easily see how big the disk footprint of his data is. Whow - what an info. Anything else? Why not changing the naming to be something like this: /catalog_tables/pg_... /catalog_index/pg_... /user_tables/oid_... /user_index/oid_... /temp_tables/oid_... /temp_index/oid_... /toast_tables/oid_... /toast_index/oid_... /whatnot_???/... This way, it would be much easier to separate all the different object types to different physical media. We would loose some transparency, but I've allways wondered what people USE that for (except for just wanna know). For convinience we could implement another little utility that tells the object size like DESCRIBE TABLE/VIEW/whatnot that returns the physical location and storage details of the object. And psql could use it to print this info additional on the \d commands. Would give unprivileged users access to this info, so be it, it's not a security issue IMHO. The subdirectory an object goes into has to be controlled by the relkind. So we need to tidy up that a little too. I think it's worth it. The objects storage location (the bare file) now would contain the OID. So we avoid naming conflicts for temp tables, naming conflicts during DROP/CREATE in a transaction and all the like. Comments? Jan -- #======================================================================# # It's easier to get forgiveness for being wrong than for being right. # # Let's break this rule - forgive me. # #================================================== JanWieck@Yahoo.com # From tgl@sss.pgh.pa.us Wed Jun 14 22:06:54 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA02821 for ; Wed, 14 Jun 2000 22:06:52 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id WAA16609; Wed, 14 Jun 2000 22:07:16 -0400 (EDT) To: Jan Wieck cc: Oliver Elphick , Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006142043.WAA07887@hot.jw.home> References: <200006142043.WAA07887@hot.jw.home> Comments: In-reply-to JanWieck@t-online.de (Jan Wieck) message dated "Wed, 14 Jun 2000 22:43:39 +0200" Date: Wed, 14 Jun 2000 22:07:15 -0400 Message-ID: <16606.961034835@sss.pgh.pa.us> From: Tom Lane Status: RO JanWieck@t-online.de (Jan Wieck) writes: > I've never been really happy with the file naming > conventions. The need of a filesystem entry to have the same > name of the DB object that is associated with it isn't right. > I know, some people love to be able to easily identify the > files with ls(1). OTOH what is that good for? I agree with Jan on this: let's just change the file names over to be OIDs. Then we can have rollbackable DROP and RENAME TABLE easily. Naming the files after the logical names of the tables is nice if it doesn't cost anything, but it is *not* worth the trouble to preserve a relationship between filename and tablename when it is costing us. And it's costing us big time. That single feature is hurting us on functionality, robustness, and portability, and for what benefit? Not nearly enough. It's time to just let go of it. > Why not changing the naming to be something like this: > /catalog_tables/pg_... > /catalog_index/pg_... > /user_tables/oid_... > /user_index/oid_... > /temp_tables/oid_... > /temp_index/oid_... > /toast_tables/oid_... > /toast_index/oid_... > /whatnot_???/... I don't see a lot of value in that. Better to do something like tablespaces: // regards, tom lane From tgl@sss.pgh.pa.us Wed Jun 14 22:20:59 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA25561 for ; Wed, 14 Jun 2000 22:20:56 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id WAA16708; Wed, 14 Jun 2000 22:21:30 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006142313.TAA22904@candle.pha.pa.us> References: <200006142313.TAA22904@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 19:13:47 -0400" Date: Wed, 14 Jun 2000 22:21:30 -0400 Message-ID: <16705.961035690@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > You need something that works from the command line, and something that > works if PostgreSQL is not running. How would you restore one file from > a tape. "Restore one file from a tape"? How are you going to do that anyway? You can't save and restore portions of a database like that, because of transaction commit status problems. To restore table X correctly, you'd have to restore pg_log as well, and then your other tables are hosed --- unless you also restore all of them from the backup. Only a complete database restore from tape would work, and for that you don't need to tell which file is which. So the above argument is a red herring. I realize it's nice to be able to tell which table file is which by eyeball, but the price we are paying for that small convenience is just too high. Give that up, and we can have rollbackable DROP and RENAME now (I'll personally commit to making it happen for 7.1). Continue to insist on it, and I don't think we'll *ever* have those features in a really robust form. It's just not possible to do multiple file renames atomically. regards, tom lane From pgsql-hackers-owner+M3381@hub.org Wed Jun 14 22:23:25 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA05943 for ; Wed, 14 Jun 2000 22:23:24 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F2ME840721; Wed, 14 Jun 2000 22:22:14 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F2Le840155 for ; Wed, 14 Jun 2000 22:21:41 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id WAA16708; Wed, 14 Jun 2000 22:21:30 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006142313.TAA22904@candle.pha.pa.us> References: <200006142313.TAA22904@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 19:13:47 -0400" Date: Wed, 14 Jun 2000 22:21:30 -0400 Message-ID: <16705.961035690@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Bruce Momjian writes: > You need something that works from the command line, and something that > works if PostgreSQL is not running. How would you restore one file from > a tape. "Restore one file from a tape"? How are you going to do that anyway? You can't save and restore portions of a database like that, because of transaction commit status problems. To restore table X correctly, you'd have to restore pg_log as well, and then your other tables are hosed --- unless you also restore all of them from the backup. Only a complete database restore from tape would work, and for that you don't need to tell which file is which. So the above argument is a red herring. I realize it's nice to be able to tell which table file is which by eyeball, but the price we are paying for that small convenience is just too high. Give that up, and we can have rollbackable DROP and RENAME now (I'll personally commit to making it happen for 7.1). Continue to insist on it, and I don't think we'll *ever* have those features in a really robust form. It's just not possible to do multiple file renames atomically. regards, tom lane From pgsql-hackers-owner+M3382@hub.org Wed Jun 14 22:31:42 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA10091 for ; Wed, 14 Jun 2000 22:31:41 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F2UI853244; Wed, 14 Jun 2000 22:30:18 -0400 (EDT) Received: from candle.pha.pa.us (pgman@s5-03.ppp.op.net [209.152.195.67]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F2Th852641 for ; Wed, 14 Jun 2000 22:29:43 -0400 (EDT) Received: (from pgman@localhost) by candle.pha.pa.us (8.9.0/8.9.0) id WAA06576; Wed, 14 Jun 2000 22:28:53 -0400 (EDT) From: Bruce Momjian Message-Id: <200006150228.WAA06576@candle.pha.pa.us> Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <16705.961035690@sss.pgh.pa.us> "from Tom Lane at Jun 14, 2000 10:21:30 pm" To: Tom Lane Date: Wed, 14 Jun 2000 22:28:53 -0400 (EDT) CC: Jan Wieck , Oliver Elphick , PostgreSQL-development X-Mailer: ELM [version 2.4ME+ PL77 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > Bruce Momjian writes: > > You need something that works from the command line, and something that > > works if PostgreSQL is not running. How would you restore one file from > > a tape. > > "Restore one file from a tape"? How are you going to do that anyway? > You can't save and restore portions of a database like that, because > of transaction commit status problems. To restore table X correctly, > you'd have to restore pg_log as well, and then your other tables are > hosed --- unless you also restore all of them from the backup. Only > a complete database restore from tape would work, and for that you > don't need to tell which file is which. So the above argument is a > red herring. > > I realize it's nice to be able to tell which table file is which by > eyeball, but the price we are paying for that small convenience is > just too high. Give that up, and we can have rollbackable DROP and > RENAME now (I'll personally commit to making it happen for 7.1). > Continue to insist on it, and I don't think we'll *ever* have those > features in a really robust form. It's just not possible to do > multiple file renames atomically. > OK, I am flexible. (Yea, right.) :-) But seriously, let me give some background. I used Ingres, that used the VMS file system, but used strange sequential AAAF324 numbers for tables. When someone deleted a table, or we were looking at what tables were using disk space, it was impossible to find the Ingres table names that went with the file. There was a system table that showed it, but it was poorly documented, and if you deleted the table, there was no way to look on the tape to find out which file to restore. As far as pg_log, you certainly would not expect to get any information back from the time of the backup table to current, so the current pg_log would be just fine. Basically, I guess we have to do it, but we have to print the proper error messages for cases in the backend we just print the file name. Also, we have to now replace the 'ls -l' command with something that will be meaningful. Right now, we use 'ps' with args to display backend information, and ls -l to show disk information. We are going to lose that here. -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 From tgl@sss.pgh.pa.us Wed Jun 14 22:31:01 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA09340 for ; Wed, 14 Jun 2000 22:31:00 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id WAA16783 for ; Wed, 14 Jun 2000 22:31:34 -0400 (EDT) To: Bruce Momjian Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006150223.WAA06516@candle.pha.pa.us> References: <200006150223.WAA06516@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 22:23:58 -0400" Date: Wed, 14 Jun 2000 22:31:33 -0400 Message-ID: <16780.961036293@sss.pgh.pa.us> From: Tom Lane Status: RO > Can I phone you? Sure, I'm here. regards, tom lane From pgsql-hackers-owner+M3383@hub.org Wed Jun 14 22:38:29 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA27501 for ; Wed, 14 Jun 2000 22:38:28 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F2bD870244; Wed, 14 Jun 2000 22:37:13 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F2af869743 for ; Wed, 14 Jun 2000 22:36:41 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id WAA16814; Wed, 14 Jun 2000 22:36:19 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006150228.WAA06576@candle.pha.pa.us> References: <200006150228.WAA06576@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 22:28:53 -0400" Date: Wed, 14 Jun 2000 22:36:19 -0400 Message-ID: <16810.961036579@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Bruce Momjian writes: > But seriously, let me give some background. I used Ingres, that used > the VMS file system, but used strange sequential AAAF324 numbers for > tables. When someone deleted a table, or we were looking at what tables > were using disk space, it was impossible to find the Ingres table names > that went with the file. There was a system table that showed it, but > it was poorly documented, and if you deleted the table, there was no way > to look on the tape to find out which file to restore. Fair enough, but it seems to me that the answer is to expend some effort on system admin support tools. We could do a lot in that line with less effort than trying to make a fundamentally mismatched filesystem representation do what we need. regards, tom lane From tgl@sss.pgh.pa.us Wed Jun 14 23:13:35 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA06306 for ; Wed, 14 Jun 2000 23:13:26 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id XAA16988; Wed, 14 Jun 2000 23:13:53 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006150244.WAA27741@candle.pha.pa.us> References: <200006150244.WAA27741@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 22:44:16 -0400" Date: Wed, 14 Jun 2000 23:13:52 -0400 Message-ID: <16985.961038832@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > That was my point --- that in doing this change, we are taking on more > TODO items, that may detract from our main TODO items. True, but they are also TODO items that could be handled by people other than the inner circle of key developers. The actual rejiggering of table-to-filename mapping is going to have to be done by one of the small number of people who are fully up to speed on backend internals. But we've got a lot more folks who would be able (and, hopefully, willing) to design and code whatever tools are needed to make the dbadmin's job easier in the face of the new filesystem layout. I'd rather not expend a lot of core time to avoid needing those tools, especially when I feel the old approach is fatally flawed anyway. > Even gdb shows us the filename/tablename in backtraces. We are never > going to be able to reproduce that. Backtraces from *what*, exactly? 99% of the backend is still going to be dealing with the same data as ever. It might be that poking around in fd.c will be a little harder, but considering that fd.c doesn't really know or care what the files it's manipulating are anyway, I'm not convinced that this is a real issue. > I guess I don't consider table schema commands inside transactions and > such to be as big an items as the utility features we will need to > build. You've *got* to be kidding. We're constantly seeing complaints about the fact that rolling back DROP or RENAME TABLE fails --- and worse, leaves the table in a corrupted/inconsistent state. As far as I can tell, that's one of the worst robustness problems we've got left to fix. This is a big deal IMHO, and I want it to be fixed and fixed right. I don't see how to fix it right if we try to keep physical filenames tied to logical tablenames. Moreover, that restriction will continue to hurt us if we try to preserve it while implementing tablespaces, ANSI schemas, etc. regards, tom lane From pgsql-hackers-owner+M3387@hub.org Wed Jun 14 23:16:56 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA07268 for ; Wed, 14 Jun 2000 23:16:54 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F3Em841832; Wed, 14 Jun 2000 23:14:48 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F3EG841655 for ; Wed, 14 Jun 2000 23:14:16 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id XAA16988; Wed, 14 Jun 2000 23:13:53 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006150244.WAA27741@candle.pha.pa.us> References: <200006150244.WAA27741@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 22:44:16 -0400" Date: Wed, 14 Jun 2000 23:13:52 -0400 Message-ID: <16985.961038832@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Bruce Momjian writes: > That was my point --- that in doing this change, we are taking on more > TODO items, that may detract from our main TODO items. True, but they are also TODO items that could be handled by people other than the inner circle of key developers. The actual rejiggering of table-to-filename mapping is going to have to be done by one of the small number of people who are fully up to speed on backend internals. But we've got a lot more folks who would be able (and, hopefully, willing) to design and code whatever tools are needed to make the dbadmin's job easier in the face of the new filesystem layout. I'd rather not expend a lot of core time to avoid needing those tools, especially when I feel the old approach is fatally flawed anyway. > Even gdb shows us the filename/tablename in backtraces. We are never > going to be able to reproduce that. Backtraces from *what*, exactly? 99% of the backend is still going to be dealing with the same data as ever. It might be that poking around in fd.c will be a little harder, but considering that fd.c doesn't really know or care what the files it's manipulating are anyway, I'm not convinced that this is a real issue. > I guess I don't consider table schema commands inside transactions and > such to be as big an items as the utility features we will need to > build. You've *got* to be kidding. We're constantly seeing complaints about the fact that rolling back DROP or RENAME TABLE fails --- and worse, leaves the table in a corrupted/inconsistent state. As far as I can tell, that's one of the worst robustness problems we've got left to fix. This is a big deal IMHO, and I want it to be fixed and fixed right. I don't see how to fix it right if we try to keep physical filenames tied to logical tablenames. Moreover, that restriction will continue to hurt us if we try to preserve it while implementing tablespaces, ANSI schemas, etc. regards, tom lane From pgsql-hackers-owner+M3397@hub.org Thu Jun 15 03:03:33 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA24286 for ; Thu, 15 Jun 2000 03:03:32 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F72T815284; Thu, 15 Jun 2000 03:02:29 -0400 (EDT) Received: from mailo.vtcif.telstra.com.au (mailo.vtcif.telstra.com.au [202.12.144.17]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F721814963 for ; Thu, 15 Jun 2000 03:02:01 -0400 (EDT) Received: (from uucp@localhost) by mailo.vtcif.telstra.com.au (8.8.2/8.6.9) id RAA01186; Thu, 15 Jun 2000 17:01:48 +1000 (EST) Received: from maili.vtcif.telstra.com.au(202.12.142.17) via SMTP by mailo.vtcif.telstra.com.au, id smtpd0SbI.z; Thu Jun 15 17:00:39 2000 Received: (from uucp@localhost) by maili.vtcif.telstra.com.au (8.8.2/8.6.9) id RAA21419; Thu, 15 Jun 2000 17:00:37 +1000 (EST) Received: from localhost(127.0.0.1), claiming to be "mail.cdn.telstra.com.au" via SMTP by localhost, id smtpdWTHrU_; Thu Jun 15 16:59:34 2000 Received: from lunitari.nimrod.itg.telecom.com.au (lunitari.nimrod.itg.telecom.com.au [192.53.254.48]) by mail.cdn.telstra.com.au (8.8.2/8.6.9) with ESMTP id QAA04796; Thu, 15 Jun 2000 16:59:33 +1000 (EST) Received: from nimrod.itg.telecom.com.au (majere [192.53.254.45]) by lunitari.nimrod.itg.telecom.com.au (8.9.1/8.9.3) with ESMTP id QAA18056; Thu, 15 Jun 2000 16:58:17 +1000 (EST) Message-ID: <39487E0C.970680AB@nimrod.itg.telecom.com.au> Date: Thu, 15 Jun 2000 16:56:12 +1000 From: Chris Bitmead Organization: IBM Global Services X-Mailer: Mozilla 4.6 [en] (X11; I; SunOS 5.6 sun4u) X-Accept-Language: en MIME-Version: 1.0 To: "Ross J. Reedstrom" CC: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items References: <16985.961038832@sss.pgh.pa.us> <200006150321.XAA09510@candle.pha.pa.us> <20000615010312.A995@rice.edu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Ross J. Reedstrom" wrote: > Any strong objections to the mixed relname_oid solution? It gets us > everything oids does, and still lets Bruce use 'ls -l' to find the big > tables, putting off writing any admin tools that'll need to be rewritten, > anyway. Doesn't relname_oid defeat the purpose of oid file names, which is that they don't change when the table is renamed? Wasn't it going to be oids with a tool to create a symlink of relname -> oid ? From pgsql-hackers-owner+M3400@hub.org Thu Jun 15 03:31:16 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA24604 for ; Thu, 15 Jun 2000 03:31:15 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA01191 for ; Thu, 15 Jun 2000 03:15:28 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F7CP835301; Thu, 15 Jun 2000 03:12:25 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F7Bt833744 for ; Thu, 15 Jun 2000 03:11:55 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id DAA18801; Thu, 15 Jun 2000 03:11:53 -0400 (EDT) To: "Ross J. Reedstrom" cc: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <20000615010312.A995@rice.edu> References: <16985.961038832@sss.pgh.pa.us> <200006150321.XAA09510@candle.pha.pa.us> <20000615010312.A995@rice.edu> Comments: In-reply-to "Ross J. Reedstrom" message dated "Thu, 15 Jun 2000 01:03:12 -0500" Date: Thu, 15 Jun 2000 03:11:52 -0400 Message-ID: <18798.961053112@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Ross J. Reedstrom" writes: > Any strong objections to the mixed relname_oid solution? Yes! You cannot make it work reliably unless the relname part is the original relname and does not track ALTER TABLE RENAME. IMHO having an obsolete relname in the filename is worse than not having the relname at all; it's a recipe for confusion, it means you still need admin tools to tell which end is really up, and what's worst is you might think you don't. Furthermore it requires an additional column in pg_class to keep track of the original relname, which is a waste of space and effort. It also creates a portability risk, or at least fails to remove one, since you are critically dependent on the assumption that the OS supports long filenames --- on a filesystem that truncates names to less than about 45 characters you're in very deep trouble. An OID-only approach still works on traditional 14-char-filename Unix filesystems (it'd mostly even work on DOS 8+3, though I doubt we care about that). Finally, one of the reasons I want to go to filenames based only on OID is that that'll make life easier for mdblindwrt. Original relname + OID doesn't help, in fact it makes life harder (more shmem space needed to keep track of the filename for each buffer). Can we *PLEASE JUST LET GO* of this bad idea? No relname in the filename. Period. regards, tom lane From tgl@sss.pgh.pa.us Thu Jun 15 03:31:11 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA24592 for ; Thu, 15 Jun 2000 03:31:10 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA01213 for ; Thu, 15 Jun 2000 03:15:46 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id DAA18833; Thu, 15 Jun 2000 03:14:30 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006150321.XAA09510@candle.pha.pa.us> References: <200006150321.XAA09510@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 23:21:15 -0400" Date: Thu, 15 Jun 2000 03:14:30 -0400 Message-ID: <18830.961053270@sss.pgh.pa.us> From: Tom Lane Status: RO Bruce Momjian writes: > Well, we did have someone do a test implementation of oid file names, > and their report was that is looked pretty ugly. However, if people are > convinced it has to be done, we can get started. I guess I was waiting > for Vadim's storage manager, where the whole idea of separate files is > going to go away anyway, I suspect. We would then have to re-write all > our admin tools for the new format. I seem to recall him saying that he wanted to go to filename == OID just like I'm suggesting. But I agree we probably ought to hold off doing anything until he gets back from Russia and can let us know whether that's still his plan. If he is planning one-huge-file or something like that, we might as well let these issues go unfixed for one more release cycle. regards, tom lane From pgsql-hackers-owner+M3401@hub.org Thu Jun 15 03:31:15 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA24601 for ; Thu, 15 Jun 2000 03:31:14 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA01428 for ; Thu, 15 Jun 2000 03:19:39 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F7GP843802; Thu, 15 Jun 2000 03:16:25 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F7Fr842651 for ; Thu, 15 Jun 2000 03:15:53 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id DAA18833; Thu, 15 Jun 2000 03:14:30 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006150321.XAA09510@candle.pha.pa.us> References: <200006150321.XAA09510@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 14 Jun 2000 23:21:15 -0400" Date: Thu, 15 Jun 2000 03:14:30 -0400 Message-ID: <18830.961053270@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Bruce Momjian writes: > Well, we did have someone do a test implementation of oid file names, > and their report was that is looked pretty ugly. However, if people are > convinced it has to be done, we can get started. I guess I was waiting > for Vadim's storage manager, where the whole idea of separate files is > going to go away anyway, I suspect. We would then have to re-write all > our admin tools for the new format. I seem to recall him saying that he wanted to go to filename == OID just like I'm suggesting. But I agree we probably ought to hold off doing anything until he gets back from Russia and can let us know whether that's still his plan. If he is planning one-huge-file or something like that, we might as well let these issues go unfixed for one more release cycle. regards, tom lane From ZeugswetterA@wien.spardat.at Thu Jun 15 03:30:59 2000 Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA24584 for ; Thu, 15 Jun 2000 03:30:56 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id JAA29140; Thu, 15 Jun 2000 09:31:12 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Thu, 15 Jun 2000 09:31:12 +0200 Message-ID: <219F68D65015D011A8E000006F8590C604AF7DE4@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" , Bruce Momjian Cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: AW: [HACKERS] Big 7.1 open items Date: Thu, 15 Jun 2000 09:31:11 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Status: RO > Bruce Momjian writes: > > You need something that works from the command line, and > something that > > works if PostgreSQL is not running. How would you restore > one file from > > a tape. > > "Restore one file from a tape"? How are you going to do that anyway? > You can't save and restore portions of a database like that, because > of transaction commit status problems. To restore table X correctly, > you'd have to restore pg_log as well, and then your other tables are > hosed --- unless you also restore all of them from the backup. Only > a complete database restore from tape would work, and for that you > don't need to tell which file is which. So the above argument is a > red herring. >From what I know it is possible to simply restore one table file since pg_log keeps all tid's. Of course it cannot guarantee integrity and does not work if the table was altered. > I realize it's nice to be able to tell which table file is which by > eyeball, but the price we are paying for that small convenience is > just too high. Give that up, and we can have rollbackable DROP and > RENAME now (I'll personally commit to making it happen for 7.1). > Continue to insist on it, and I don't think we'll *ever* have those > features in a really robust form. It's just not possible to do > multiple file renames atomically. In the last proposal Bruce and I had it all layed out for tabname + oid with no overhead in the normal situation, and little overhead if a rename table crashed or was not rolled back or committed properly which imho had all advantages combined. Andreas From ZeugswetterA@wien.spardat.at Thu Jun 15 04:31:04 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA25144 for ; Thu, 15 Jun 2000 04:31:03 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id EAA03225 for ; Thu, 15 Jun 2000 04:05:41 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id KAA100894; Thu, 15 Jun 2000 10:04:52 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Thu, 15 Jun 2000 10:04:52 +0200 Message-ID: <219F68D65015D011A8E000006F8590C604AF7DE7@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Don Baccus'" , Bruce Momjian , Tom Lane Cc: Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: AW: [HACKERS] Big 7.1 open items Date: Thu, 15 Jun 2000 10:04:51 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="windows-1252" Status: RO > In reality, very few people are going to be interested in restoring > a table in a way that breaks referential integrity and other > normal assumptions about what exists in the database. This is not true. In my DBA history it would have saved me manweeks of work if an easy and efficient restore of one single table from backup would have been available in Informix and Oracle. We allways had to restore most of the whole system to another machine only to get back at some table info that would then be manually re-added to the production system. A restore of one table to a different/new tablename would have been very convenient, and this is currently possible in PostgreSQL. (create new table with same schema, then replace new table data file with file from backup) > The reality > is that most people are going to engage in a little time travel > to a past, consistent backup rather than do as you suggest. No, this is what is done most of the time, but it is very inconvenient to tell people that they loose all work from past days, so it is usually done as I noted above if possible. We once had a situation where all data was deleted from a table, but the problem was only noticed 3 weeks later. > This is going to be more and more true as Postgres gains more and > more acceptance in (no offense intended) the real world. > > >Right now, we use 'ps' with args to display backend > information, and ls > >-l to show disk information. We are going to lose that here. > > Dependence on "ls -l" is, IMO, a very weak argument. In normal situations where everything works I agree, it is the error situations where it really helps if you see what data is where. debugging, lsof, Bruce already named them. Andreas From pgsql-hackers-owner+M3405@hub.org Thu Jun 15 04:31:09 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA25151 for ; Thu, 15 Jun 2000 04:31:07 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id EAA04151 for ; Thu, 15 Jun 2000 04:30:23 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F8RI883087; Thu, 15 Jun 2000 04:27:18 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F8Qx881928 for ; Thu, 15 Jun 2000 04:27:00 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id KAA79848; Thu, 15 Jun 2000 10:26:13 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Thu, 15 Jun 2000 10:26:14 +0200 Message-ID: <219F68D65015D011A8E000006F8590C604AF7DE8@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" , "Ross J. Reedstrom" Cc: PostgreSQL-development Subject: AW: [HACKERS] Big 7.1 open items Date: Thu, 15 Jun 2000 10:26:12 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr > "Ross J. Reedstrom" writes: > > Any strong objections to the mixed relname_oid solution? > > Yes! > > You cannot make it work reliably unless the relname part is > the original > relname and does not track ALTER TABLE RENAME. It does, or should at least. Only problem case is where db crashes during alter or commit/rollback. This could be fixed by first open that fails to find the file or vacuum, or some other utility. > IMHO having > an obsolete > relname in the filename is worse than not having the relname at all; > it's a recipe for confusion, it means you still need admin > tools to tell > which end is really up, and what's worst is you might think you don't. > > Furthermore it requires an additional column in pg_class to keep track > of the original relname, which is a waste of space and effort. it does not. > Finally, one of the reasons I want to go to filenames based > only on OID > is that that'll make life easier for mdblindwrt. Original > relname + OID > doesn't help, in fact it makes life harder (more shmem space needed to > keep track of the filename for each buffer). I do not see this. filename is constructed from relname+oid. if not found, do directory scan for *_.dat, if found --> rename. Andreas From pgsql-hackers-owner+M3407@hub.org Thu Jun 15 05:01:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id FAA25462 for ; Thu, 15 Jun 2000 05:01:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id EAA04667 for ; Thu, 15 Jun 2000 04:45:51 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5F8gr817124; Thu, 15 Jun 2000 04:42:53 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by hub.org (8.10.1/8.10.1) with ESMTP id e5F8gX815763 for ; Thu, 15 Jun 2000 04:42:34 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id KAA29072; Thu, 15 Jun 2000 10:41:51 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Thu, 15 Jun 2000 10:41:51 +0200 Message-ID: <219F68D65015D011A8E000006F8590C604AF7DE9@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" Cc: PostgreSQL-development Subject: AW: [HACKERS] Big 7.1 open items Date: Thu, 15 Jun 2000 10:41:50 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > It's just not possible to do > multiple file renames atomically. This is not necessary, since *_ is unique regardless of relname prefix. Andreas From scrappy@hub.org Thu Jun 15 08:30:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id IAA03846 for ; Thu, 15 Jun 2000 08:30:58 -0400 (EDT) Received: from thelab.hub.org (nat193.152.mpoweredpc.net [142.177.193.152]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id IAA14167 for ; Thu, 15 Jun 2000 08:16:58 -0400 (EDT) Received: from localhost (scrappy@localhost) by thelab.hub.org (8.9.3/8.9.3) with ESMTP id JAA74856; Thu, 15 Jun 2000 09:14:29 -0300 (ADT) (envelope-from scrappy@hub.org) X-Authentication-Warning: thelab.hub.org: scrappy owned process doing -bs Date: Thu, 15 Jun 2000 09:14:29 -0300 (ADT) From: The Hermit Hacker To: Bruce Momjian cc: Tom Lane , Jan Wieck , Oliver Elphick , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <200006150321.XAA09510@candle.pha.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO On Wed, 14 Jun 2000, Bruce Momjian wrote: > > Backtraces from *what*, exactly? 99% of the backend is still going > > to be dealing with the same data as ever. It might be that poking > > around in fd.c will be a little harder, but considering that fd.c > > doesn't really know or care what the files it's manipulating are > > anyway, I'm not convinced that this is a real issue. > > I was just throwing gdb out as an example. The bigger ones are ls, > lsof/fstat, and tar. You've lost me on this one ... if someone does an lsof of the process, it will still provide them a list of open files ... are you complaining about the extra step required to translate the file name to a "valid table"? Oh, one point here ... this whole 'filenaming issue' ... as far as ls is concerned, at least, only affects the superuser, since he's the only one that can go 'ls'ng around i nthe directories ... And, ummm, how hard would it be to have \d in psql display the "physical table name" as part of its output? Slight tangent here: One thing that I think would be great if we could add is some sort of: SELECT db_name, disk_space; query wher a database owner, not the superuser, could see how much disk space their tables are using up ... possible? From pgsql-hackers-owner+M3412@hub.org Thu Jun 15 08:30:55 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id IAA03842 for ; Thu, 15 Jun 2000 08:30:54 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id IAA15241 for ; Thu, 15 Jun 2000 08:31:29 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5FCSM877572; Thu, 15 Jun 2000 08:28:22 -0400 (EDT) Received: from zrtps06s.us.nortel.com ([47.140.48.50]) by hub.org (8.10.1/8.10.1) with ESMTP id e5FCRS877255 for ; Thu, 15 Jun 2000 08:27:28 -0400 (EDT) Received: from ertpg15e1.nortelnetworks.com (actually zrtph06n.us.nortel.com) by zrtps06s.us.nortel.com; Thu, 15 Jun 2000 08:26:34 -0400 Received: from zrtpd004.us.nortel.com (actually zrtpd004) by ertpg15e1.nortelnetworks.com; Thu, 15 Jun 2000 08:26:11 -0400 Received: from zrtpd003.us.nortel.com ([47.140.224.137]) by zrtpd004.us.nortel.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2650.21) id MPQCZWMM; Thu, 15 Jun 2000 08:26:10 -0400 Received: from americasm01.nt.com (hrtpp28d.us.nortel.com [47.190.110.250]) by zrtpd003.us.nortel.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2650.21) id L1N0XG78; Thu, 15 Jun 2000 08:26:12 -0400 Message-ID: <3948CBDC.5A4F5705@americasm01.nt.com> Date: Thu, 15 Jun 2000 08:28:12 -0400 X-Sybari-Space: 00000000 00000000 00000000 From: "Mark Hollomon" Reply-To: "Mark Hollomon" Organization: Nortel Networks X-Mailer: Mozilla 4.04 [en] (Win95; U) MIME-Version: 1.0 To: "Ross J. Reedstrom" CC: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items References: <16985.961038832@sss.pgh.pa.us> <200006150321.XAA09510@candle.pha.pa.us> <20000615010312.A995@rice.edu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Orig: X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Ross J. Reedstrom wrote: > > Any strong objections to the mixed relname_oid solution? It gets us > everything oids does, and still lets Bruce use 'ls -l' to find the big > tables, putting off writing any admin tools that'll need to be rewritten, > anyway. I would object to the mixed name. Consider: CREATE TABLE FOO .... ALTER TABLE FOO RENAME FOO_OLD; CREATE TABLE FOO .... For the same atomicity reason, rename can't change the name of the files. So, which foo_ is the FOO_OLD and which is FOO? In other words, in the presence of rename, putting relname in the filename is misleading at best. -- Mark Hollomon mhh@nortelnetworks.com ESN 451-9008 (302)454-9008 From pgsql-hackers-owner+M3413@hub.org Thu Jun 15 08:30:47 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id IAA03837 for ; Thu, 15 Jun 2000 08:30:45 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5FCTb883200; Thu, 15 Jun 2000 08:29:37 -0400 (EDT) Received: from smtp1.andrew.cmu.edu (SMTP1.ANDREW.CMU.EDU [128.2.10.81]) by hub.org (8.10.1/8.10.1) with ESMTP id e5FCT7881265 for ; Thu, 15 Jun 2000 08:29:07 -0400 (EDT) Received: from export.andrew.cmu.edu (EXPORT.ANDREW.CMU.EDU [128.2.23.2]) by smtp1.andrew.cmu.edu (8.9.3/8.9.3) with ESMTP id IAA02782 for ; Thu, 15 Jun 2000 08:29:02 -0400 (EDT) Date: Thu, 15 Jun 2000 08:29:02 -0400 (EDT) Message-Id: <200006151229.IAA02782@smtp1.andrew.cmu.edu> From: Brian E Gallew X-Mailer: BatIMail version 3.2 To: "PostgreSQL-development" In-reply-to: <16810.961036579@sss.pgh.pa.us> Subject: Re: [HACKERS] Big 7.1 open items References: <200006150228.WAA06576@candle.pha.pa.us> <16810.961036579@sss.pgh.pa.us> Mime-Version: 1.0 (generated by tm-edit 7.106) Content-Type: multipart/signed; protocol="application/pgp-signature"; boundary="pgp-sign-Multipart_Thu_Jun_15_08:29:00_2000-1"; micalg=pgp-md5 Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO --pgp-sign-Multipart_Thu_Jun_15_08:29:00_2000-1 Content-Type: text/plain; charset=US-ASCII Then spoke up and said: > Precedence: bulk > > Bruce Momjian writes: > > But seriously, let me give some background. I used Ingres, that used > > the VMS file system, but used strange sequential AAAF324 numbers for > > tables. When someone deleted a table, or we were looking at what tables > > were using disk space, it was impossible to find the Ingres table names > > that went with the file. There was a system table that showed it, but > > it was poorly documented, and if you deleted the table, there was no way > > to look on the tape to find out which file to restore. > > Fair enough, but it seems to me that the answer is to expend some effort > on system admin support tools. We could do a lot in that line with less > effort than trying to make a fundamentally mismatched filesystem > representation do what we need. We've been an Ingres shop as long as there's been an Ingres. While we've also had the problem Bruce noticed with table names, we've *also* used the trivial fix of running a (simple) Report Writer job each night, immediately before the backup, that lists all of the database tables/indicies and the underlying files. True, if someone drops/recreates a table twice between backups we can't find the intermediate file name, but since we also haven't backed up that filename, this isn't an issue. Also, the consistency issue is really not as important as you would think. If you are restoring a table, you want the information in it, whether or not it's consistent with anything else. I've done hundreds of table restores (can you say "modify table to heap"?) and never once has inconsistency been an issue. Oh, yeah, and we don't shut the database down for this, either. (That last isn't my choice, BTW.) -- ===================================================================== | JAVA must have been developed in the wilds of West Virginia. | | After all, why else would it support only single inheritance?? | ===================================================================== | Finger geek@cmu.edu for my public key. | ===================================================================== --pgp-sign-Multipart_Thu_Jun_15_08:29:00_2000-1 Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit -----BEGIN PGP MESSAGE----- Version: 2.6.2 Comment: Processed by Mailcrypt 3.3, an Emacs/PGP interface iQBVAwUBOUjMDYdzVnzma+gdAQHUowH+JglNasUWT5RKSnF3pzNdy5nyrGmLhbWa Oom1oUqToxcyfjVFL34dXpnIlvNHO0K2Di4NKZ9HykwOHzrnExf15w== =yXoe -----END PGP MESSAGE----- --pgp-sign-Multipart_Thu_Jun_15_08:29:00_2000-1-- From dhogaza@pacifier.com Thu Jun 15 09:31:05 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id JAA04418 for ; Thu, 15 Jun 2000 09:31:04 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id JAA20080 for ; Thu, 15 Jun 2000 09:22:36 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id GAA05755; Thu, 15 Jun 2000 06:21:54 -0700 (PDT) Message-Id: <3.0.1.32.20000615054049.011bcec0@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Thu, 15 Jun 2000 05:40:49 -0700 To: Zeugswetter Andreas SB , Bruce Momjian , Tom Lane From: Don Baccus Subject: Re: AW: [HACKERS] Big 7.1 open items Cc: Jan Wieck , Oliver Elphick , PostgreSQL-development In-Reply-To: <219F68D65015D011A8E000006F8590C604AF7DE7@sdexcsrv1.f000.d0 188.sd.spardat.at> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 10:04 AM 6/15/00 +0200, Zeugswetter Andreas SB wrote: > >> In reality, very few people are going to be interested in restoring >> a table in a way that breaks referential integrity and other >> normal assumptions about what exists in the database. > >This is not true. In my DBA history it would have saved me manweeks >of work if an easy and efficient restore of one single table from backup >would have been available in Informix and Oracle. >We allways had to restore most of the whole system to another machine only >to get back at some table info that would then be manually re-added >to the production system. I'm missing something, I guess. You would do a createdb, do a filesystem copy of pg_log and one file into it, and then read data from the table without having to restore the other tables in the database? I'm just curious - when was the last time you restored a Postgres database in this piecemeal manner, and how often do you do it? - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From pgsql-hackers-owner+M3440@hub.org Thu Jun 15 14:46:22 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA04607 for ; Thu, 15 Jun 2000 14:46:21 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA12695 for ; Thu, 15 Jun 2000 12:48:58 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5FGjXI40370; Thu, 15 Jun 2000 12:45:33 -0400 (EDT) Received: from wallace.ece.rice.edu (wallace.ece.rice.edu [128.42.12.154]) by hub.org (8.10.1/8.10.1) with ESMTP id e5FGjJI39359 for ; Thu, 15 Jun 2000 12:45:20 -0400 (EDT) Received: by rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for pgsql-hackers@postgresql.org; Thu, 15 Jun 2000 11:45:19 -0500 (CDT) Date: Thu, 15 Jun 2000 11:45:19 -0500 From: "Ross J. Reedstrom" To: Tom Lane Cc: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items Message-ID: <20000615114519.B3939@rice.edu> Mail-Followup-To: Tom Lane , PostgreSQL-development References: <16985.961038832@sss.pgh.pa.us> <200006150321.XAA09510@candle.pha.pa.us> <20000615010312.A995@rice.edu> <18798.961053112@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii User-Agent: Mutt/1.0i In-Reply-To: <18798.961053112@sss.pgh.pa.us>; from tgl@sss.pgh.pa.us on Thu, Jun 15, 2000 at 03:11:52AM -0400 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr On Thu, Jun 15, 2000 at 03:11:52AM -0400, Tom Lane wrote: > "Ross J. Reedstrom" writes: > > Any strong objections to the mixed relname_oid solution? > > Yes! > > You cannot make it work reliably unless the relname part is the original > relname and does not track ALTER TABLE RENAME. IMHO having an obsolete > relname in the filename is worse than not having the relname at all; > it's a recipe for confusion, it means you still need admin tools to tell > which end is really up, and what's worst is you might think you don't. The plan here was to let VACUUM handle renaming the file, since it will already have all the necessary locks. This shortens the window of confusion. ALTER TABLE RENAME doesn't happen that often, really - the relname is there just for human consumption, then. > > Furthermore it requires an additional column in pg_class to keep track > of the original relname, which is a waste of space and effort. > I actually started down this path thinking about implementing SCHEMA, since tables in the same DB but in different schema can have the same relname, I figured I needed to change that. We'll need something in pg_class to keep track of what schema a relation is in, instead. > It also creates a portability risk, or at least fails to remove one, > since you are critically dependent on the assumption that the OS > supports long filenames --- on a filesystem that truncates names to less > than about 45 characters you're in very deep trouble. An OID-only > approach still works on traditional 14-char-filename Unix filesystems > (it'd mostly even work on DOS 8+3, though I doubt we care about that). Actually, no. Since I store the filename in a name attribute, I used this nifty function somebody wrote, makeObjectName, to trim the relname part, but leave the oid. (Yes, I know it's yours ;-) > > Finally, one of the reasons I want to go to filenames based only on OID > is that that'll make life easier for mdblindwrt. Original relname + OID > doesn't help, in fact it makes life harder (more shmem space needed to > keep track of the filename for each buffer). Can you explain in more detail how this helps? Not by letting the bufmgr know that oid == filename, I hope. We need to improving the abstraction of the smgr, not add another violation. Ah, sorry, mdblindwrt _is_ in the smgr. Hmm, grovelling through that code, I see how it could be simpler if reloid == filename. Heck, we even get to save shmem in the buffdesc.blind part, since we only need the dbname in there, now. Hmm, I see I missed the relpath_blind() in my patch - oops. (relpath() is always called with RelationGetPhysicalRelationName(), and that's where I was putting in the relphysname) Hmm, what's all this with functions in catalog.c that are only called by smgr/md.c? seems to me that anything having to do with physical storage (like the path!) belongs in the smgr abstraction. > > Can we *PLEASE JUST LET GO* of this bad idea? No relname in the > filename. Period. > Gee, so dogmatic. No one besides Bruce and Hiroshi discussed this _at all_ when I first put up patches two month ago. O.K., I'll do the oids only version (and fix up relpath_blind) Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 From Inoue@tpf.co.jp Thu Jun 15 17:45:40 2000 Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA27548 for ; Thu, 15 Jun 2000 17:45:37 -0400 (EDT) Received: from mcadnote1 (ppm122.noc.fukui.nsk.ne.jp [210.161.188.41]) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id GAA07248; Fri, 16 Jun 2000 06:45:30 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" , "Ross J. Reedstrom" Cc: "Tom Lane" , "PostgreSQL-development" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 06:48:21 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) In-Reply-To: <200006151935.PAA17512@candle.pha.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Importance: Normal Status: ROr > -----Original Message----- > From: pgsql-hackers-owner@hub.org > [mailto:pgsql-hackers-owner@hub.org]On Behalf Of Bruce Momjian > > > > Can we *PLEASE JUST LET GO* of this bad idea? No relname in the > > > filename. Period. > > > > > > > Gee, so dogmatic. No one besides Bruce and Hiroshi discussed this _at > > all_ when I first put up patches two month ago. O.K., I'll do the oids > > only version (and fix up relpath_blind) > > Hold on. I don't think we want that work done yet. Seems even Tom is > thinking that if Vadim is going to re-do everything later anyway, we may > be better with a relname/oid solution that does require additional > administration apps. > Hmm,why is naming rule first ? I've never enphasized naming rule except that it should be unique. It has been my main point to reduce the necessity of naming rule as possible. IIRC,by keeping the stored place in pg_class,Ross's trial patch remains only 2 places where naming rule is required. So wouldn't we be free from naming rule(it would not be so difficult to change naming rule if the rule is found to be bad) ? I've also mentioned many times neither relname nor oid is sufficient for the uniqueness. In addiiton neither relname nor oid would be necessary for the uniqueness. IMHO,it's bad to rely on the item which is neither necessary nor sufficient. I proposed relname+unique_id naming once. The unique_id is independent from oid. The relname is only for convinience for DBA and so we don't have to change it due to RENAME. Db's consistency is much more important than dba's satis- faction. Comments ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3448@hub.org Thu Jun 15 19:01:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA00764 for ; Thu, 15 Jun 2000 19:01:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id SAA17328 for ; Thu, 15 Jun 2000 18:57:32 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5FMsMI97744; Thu, 15 Jun 2000 18:54:22 -0400 (EDT) Received: from wallace.ece.rice.edu (wallace.ece.rice.edu [128.42.12.154]) by hub.org (8.10.1/8.10.1) with ESMTP id e5FMs0I94252 for ; Thu, 15 Jun 2000 18:54:00 -0400 (EDT) Received: by rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for pgsql-hackers@postgresql.org; Thu, 15 Jun 2000 17:53:59 -0500 (CDT) Date: Thu, 15 Jun 2000 17:53:59 -0500 From: "Ross J. Reedstrom" To: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items Message-ID: <20000615175359.A12194@rice.edu> Mail-Followup-To: PostgreSQL-development References: <200006152148.RAA27790@candle.pha.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii User-Agent: Mutt/1.0i In-Reply-To: <200006152148.RAA27790@candle.pha.pa.us>; from pgman@candle.pha.pa.us on Thu, Jun 15, 2000 at 05:48:59PM -0400 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO On Thu, Jun 15, 2000 at 05:48:59PM -0400, Bruce Momjian wrote: > > I've also mentioned many times neither relname nor oid is sufficient > > for the uniqueness. In addiiton neither relname nor oid would be > > necessary for the uniqueness. > > IMHO,it's bad to rely on the item which is neither necessary nor > > sufficient. > > I proposed relname+unique_id naming once. The unique_id is > > independent from oid. The relname is only for convinience for > > DBA and so we don't have to change it due to RENAME. > > Db's consistency is much more important than dba's satis- > > faction. > > > > Comments ? > > I am happy not to rename the file on 'RENAME', but seems no one likes > that. Good, 'cause that's how I've implemented it so far. Actually, all I've done is port my previous patch to current, with one little change: I added a macro RelationGetRealRelationName which does what RelationGetPhysicalRelationName used to do: i.e. return the relname with no temptable funny business, and used that for the relcache macros. It passes all the serial regression tests: I haven't run the parallel tests yet. ALTER TABLE RENAME rollsback nicely. I'll need to learn some omre about xacts to get DROP TABLE rolling back. I'll drop it on PATCHES right now, for comment. Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 From pgsql-hackers-owner+M3451@hub.org Thu Jun 15 20:01:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA01651 for ; Thu, 15 Jun 2000 20:00:59 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA20985 for ; Thu, 15 Jun 2000 19:57:49 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5FNsgI25402; Thu, 15 Jun 2000 19:54:42 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5FNsCI22412 for ; Thu, 15 Jun 2000 19:54:12 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id TAA02263; Thu, 15 Jun 2000 19:53:52 -0400 (EDT) To: "Ross J. Reedstrom" cc: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <20000615114519.B3939@rice.edu> References: <16985.961038832@sss.pgh.pa.us> <200006150321.XAA09510@candle.pha.pa.us> <20000615010312.A995@rice.edu> <18798.961053112@sss.pgh.pa.us> <20000615114519.B3939@rice.edu> Comments: In-reply-to "Ross J. Reedstrom" message dated "Thu, 15 Jun 2000 11:45:19 -0500" Date: Thu, 15 Jun 2000 19:53:52 -0400 Message-ID: <2260.961113232@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Ross J. Reedstrom" writes: > On Thu, Jun 15, 2000 at 03:11:52AM -0400, Tom Lane wrote: >> "Ross J. Reedstrom" writes: >>>> Any strong objections to the mixed relname_oid solution? >> >> Yes! > The plan here was to let VACUUM handle renaming the file, since it > will already have all the necessary locks. This shortens the window > of confusion. ALTER TABLE RENAME doesn't happen that often, really - > the relname is there just for human consumption, then. Yeah, I've seen tons of discussion of how if we do this, that, and the other thing, and be prepared to fix up some other things in case of crash recovery, we can make it work with filename == relname + OID (where relname tracks logical name, at least at some remove). Probably. Assuming nobody forgets anything. I'm just trying to point out that that's a huge amount of pretty delicate mechanism. The amount of work required to make it trustworthy looks to me to dwarf the admin tools that Bruce is complaining about. And we only have a few people competent to do the work. (With all due respect, Ross, if you weren't already aware of the implications for mdblindwrt, I have to wonder what else you missed.) Filename == OID is so simple, reliable, and straightforward by comparison that I think the decision is a no-brainer. If we could afford to sink unlimited time into this one issue then it might make sense to do it the hard way, but we have enough important stuff on our TODO list to keep us all busy for years --- I cannot believe that it's an effective use of our time to do this. > Hmm, what's all this with functions in catalog.c that are only called by > smgr/md.c? seems to me that anything having to do with physical storage > (like the path!) belongs in the smgr abstraction. Yeah, there's a bunch of stuff that should have been implemented by adding new smgr entry points, but wasn't. It should be pushed down. (I can't resist pointing out that one of those things is physical relation rename, which will go away and not *need* to be pushed down if we do it the way I want.) regards, tom lane From tgl@sss.pgh.pa.us Thu Jun 15 20:00:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA01647 for ; Thu, 15 Jun 2000 20:00:58 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA21034 for ; Thu, 15 Jun 2000 19:58:30 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id TAA02283; Thu, 15 Jun 2000 19:57:05 -0400 (EDT) To: Bruce Momjian cc: "Ross J. Reedstrom" , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006151935.PAA17512@candle.pha.pa.us> References: <200006151935.PAA17512@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Thu, 15 Jun 2000 15:35:45 -0400" Date: Thu, 15 Jun 2000 19:57:05 -0400 Message-ID: <2280.961113425@sss.pgh.pa.us> From: Tom Lane Status: RO Bruce Momjian writes: >> Gee, so dogmatic. No one besides Bruce and Hiroshi discussed this _at >> all_ when I first put up patches two month ago. O.K., I'll do the oids >> only version (and fix up relpath_blind) > Hold on. I don't think we want that work done yet. Seems even Tom is > thinking that if Vadim is going to re-do everything later anyway, we may > be better with a relname/oid solution that does require additional > administration apps. Don't put words in my mouth, please. If we are going to throw the work away later, it'd be foolish to do the much greater amount of work needed to make filename=relname+OID fly than is needed for filename=OID. However, I'm pretty sure I recall Vadim stating that he thought filename=OID would be required for his smgr changes anyway... regards, tom lane From pgsql-hackers-owner+M3453@hub.org Thu Jun 15 21:01:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA02731 for ; Thu, 15 Jun 2000 21:01:01 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id UAA23469 for ; Thu, 15 Jun 2000 20:36:36 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5G0WDI97134; Thu, 15 Jun 2000 20:32:13 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5G0VsI97003 for ; Thu, 15 Jun 2000 20:31:54 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id JAA07328; Fri, 16 Jun 2000 09:26:04 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" , "Tom Lane" Cc: "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 09:28:14 +0900 Message-ID: <000d01bfd729$c24b29c0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <2260.961113232@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Importance: Normal X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: pgsql-hackers-owner@hub.org [mailto:pgsql-hackers-owner@hub.org]On > Behalf Of Tom Lane > > "Ross J. Reedstrom" writes: > > On Thu, Jun 15, 2000 at 03:11:52AM -0400, Tom Lane wrote: > >> "Ross J. Reedstrom" writes: > >>>> Any strong objections to the mixed relname_oid solution? > >> > >> Yes! > > > The plan here was to let VACUUM handle renaming the file, since it > > will already have all the necessary locks. This shortens the window > > of confusion. ALTER TABLE RENAME doesn't happen that often, really - > > the relname is there just for human consumption, then. > > Yeah, I've seen tons of discussion of how if we do this, that, and > the other thing, and be prepared to fix up some other things in case > of crash recovery, we can make it work with filename == relname + OID > (where relname tracks logical name, at least at some remove). > I've seen little discussion of how to avoid the use of naming rule. I've proposed many times that we should keep the information where the table is stored in our database itself. I've never seen clear objections to it. So I could understand my proposal is OK ? Isn't it much more important than naming rule ? Under the mechanism,we could easily replace bad naming rule. And I believe that Ross's work is mostly around the mechanism not naming rule. Now I like neither relname nor oid because it's not sufficient for my purpose. Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Thu Jun 15 22:01:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA03637 for ; Thu, 15 Jun 2000 22:01:01 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id VAA28521 for ; Thu, 15 Jun 2000 21:58:46 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id VAA02730; Thu, 15 Jun 2000 21:57:27 -0400 (EDT) To: "Hiroshi Inoue" cc: "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <000d01bfd729$c24b29c0$2801007e@tpf.co.jp> References: <000d01bfd729$c24b29c0$2801007e@tpf.co.jp> Comments: In-reply-to "Hiroshi Inoue" message dated "Fri, 16 Jun 2000 09:28:14 +0900" Date: Thu, 15 Jun 2000 21:57:27 -0400 Message-ID: <2727.961120647@sss.pgh.pa.us> From: Tom Lane Status: ROr "Hiroshi Inoue" writes: > Now I like neither relname nor oid because it's not sufficient > for my purpose. We should probably not do much of anything with this issue until we have a clearer understanding of what we want to do about tablespaces and schemas. My gut feeling is that we will end up with pathnames that look something like .../data/base/DBNAME/TABLESPACE/OIDOFRELATION (with .N attached if a segment of a large relation, of course). The TABLESPACE "name" should likely be an OID itself, but it wouldn't have to be if you are willing to say that tablespaces aren't renamable. (Come to think of it, does anyone care about being able to rename databases? ;-)) Note that the TABLESPACE will often be a symlink to storage on another drive, rather than a plain subdirectory of the DBNAME, but that shouldn't be an issue at this level of discussion. I think that schemas probably don't enter into this. We should instead rely on the uniqueness of OIDs to prevent filename collisions. However, OIDs aren't really unique: different databases in an installation will use the same OIDs for their system tables. My feeling is that we can live with a restriction like "you can't store the system tables of different databases in the same tablespace". Alternatively we could avoid that issue by inverting the pathname order: .../data/base/TABLESPACE/DBNAME/OIDOFRELATION Note that in any case, system tables will have to live in a predetermined tablespace, since you can't very well look in pg_class to find out which tablespace pg_class lives in. Perhaps we should just reserve a tablespace per database for system tables and forget the whole issue. If we do that, there's not really any need for the database in the path! Just .../data/base/TABLESPACE/OIDOFRELATION would do fine and help reduce lookup overhead. BTW, schemas do make things interesting for the other camp: is it possible for the same table to be referenced by different names in different schemas? If so, just how useful is it to pick one of those names arbitrarily for the filename? This is an advanced version of the main objection to using the original relname and not updating it at RENAME TABLE --- sooner or later, the filenames are going to be more confusing than helpful. Comments? Have I missed something important about schemas? regards, tom lane From pgsql-hackers-owner+M3457@hub.org Thu Jun 15 22:27:45 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA04586 for ; Thu, 15 Jun 2000 22:27:44 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5G2POI23418; Thu, 15 Jun 2000 22:25:24 -0400 (EDT) Received: from candle.pha.pa.us (pgman@nav-43.dsl.navpoint.com [162.33.245.46]) by hub.org (8.10.1/8.10.1) with ESMTP id e5G2P3I23299 for ; Thu, 15 Jun 2000 22:25:04 -0400 (EDT) Received: (from pgman@localhost) by candle.pha.pa.us (8.9.0/8.9.0) id WAA04345; Thu, 15 Jun 2000 22:24:53 -0400 (EDT) From: Bruce Momjian Message-Id: <200006160224.WAA04345@candle.pha.pa.us> Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <2727.961120647@sss.pgh.pa.us> "from Tom Lane at Jun 15, 2000 09:57:27 pm" To: Tom Lane Date: Thu, 15 Jun 2000 22:24:52 -0400 (EDT) CC: Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" X-Mailer: ELM [version 2.4ME+ PL77 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > "Hiroshi Inoue" writes: > > Now I like neither relname nor oid because it's not sufficient > > for my purpose. > > We should probably not do much of anything with this issue until > we have a clearer understanding of what we want to do about > tablespaces and schemas. Here is an analysis of our options: Work required Disadvantages ---------------------------------------------------------------------------- Keep current system no work rename/create no rollback relname/oid but less work new pg_class column, no rename change filename not accurate on rename relname/oid with more work complex code rename change during vacuum oid filename less work, but confusing to admins need admin tools -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 From Inoue@tpf.co.jp Thu Jun 15 22:41:50 2000 Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA05230 for ; Thu, 15 Jun 2000 22:41:48 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id LAA07495; Fri, 16 Jun 2000 11:41:43 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 11:43:52 +0900 Message-ID: <000201bfd73c$b52873c0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <2727.961120647@sss.pgh.pa.us> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO Sorry for my previous mail. It was posted by my mistake. > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > "Hiroshi Inoue" writes: > > Now I like neither relname nor oid because it's not sufficient > > for my purpose. > > We should probably not do much of anything with this issue until > we have a clearer understanding of what we want to do about > tablespaces and schemas. > > My gut feeling is that we will end up with pathnames that look > something like > > .../data/base/DBNAME/TABLESPACE/OIDOFRELATION > Schema is a logical concept and irrevant to physical location. I strongly object your suggestion unless above means *default* location. Tablespace is an encapsulation of table allocation and the name should be irrevant to the location basically. So above seems very bad for me. Anyway I don't see any advantage in fixed mapping impleme ntation. After renewal,we should at least have a possibility to allocate a specific table in arbitrary separate directory. Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Thu Jun 15 23:31:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA06634; Thu, 15 Jun 2000 23:30:59 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id XAA03227; Thu, 15 Jun 2000 23:18:54 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id MAA07544; Fri, 16 Jun 2000 12:18:06 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" , "Tom Lane" Cc: "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 12:20:16 +0900 Message-ID: <000401bfd741$cabea100$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <200006160224.WAA04345@candle.pha.pa.us> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > "Hiroshi Inoue" writes: > > > Now I like neither relname nor oid because it's not sufficient > > > for my purpose. > > > > We should probably not do much of anything with this issue until > > we have a clearer understanding of what we want to do about > > tablespaces and schemas. > > Here is an analysis of our options: > > Work required Disadvantages > ------------------------------------------------------------------ > ---------- > > Keep current system no work rename/create > no rollback > > relname/oid but less work new pg_class column, > no rename change filename not > accurate on > rename > > relname/oid with more work complex code > rename change during > vacuum > > oid filename less work, but confusing to admins > need admin tools > Please add my opinion for naming rule. relname/unique_id but need some work new pg_class column, no relname change. for unique-id generation filename not relname Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3465@hub.org Fri Jun 16 00:01:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA06924 for ; Fri, 16 Jun 2000 00:01:00 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id XAA05470 for ; Thu, 15 Jun 2000 23:59:46 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5G3uaI10809; Thu, 15 Jun 2000 23:56:36 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5G3uKI10702 for ; Thu, 15 Jun 2000 23:56:21 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id MAA07571; Fri, 16 Jun 2000 12:55:33 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "PostgreSQL-development" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 12:57:44 +0900 Message-ID: <000501bfd747$067f0220$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <3264.961127021@sss.pgh.pa.us> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > "Hiroshi Inoue" writes: > > Please add my opinion for naming rule. > > > relname/unique_id but need some work new > pg_class column, > > no relname change. for unique-id generation filename not relname > > Why is a unique ID better than --- or even different from --- > using the relation's OID? It seems pointless to me... > For example,in the implementation of CLUSTER command, we would need another new file for the target relation in order to put sorted rows but don't we want to change the OID ? It would be needed for table re-construction generally. If I remember correectly,you once proposed OID+version naming for the cases. Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Fri Jun 16 02:01:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA08093 for ; Fri, 16 Jun 2000 02:00:59 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA10174 for ; Fri, 16 Jun 2000 01:34:44 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id OAA07656; Fri, 16 Jun 2000 14:33:12 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 14:35:21 +0900 Message-ID: <000001bfd754$a9e44f80$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <3238.961126521@sss.pgh.pa.us> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > "Hiroshi Inoue" writes: > > Tablespace is an encapsulation of table allocation and the > > name should be irrevant to the location basically. So above > > seems very bad for me. > > Anyway I don't see any advantage in fixed mapping impleme > > ntation. After renewal,we should at least have a possibility to > > allocate a specific table in arbitrary separate directory. > > Call a "directory" a "tablespace" and we're on the same page, > aren't we? Actually I'd envision some kind of admin command > "CREATE TABLESPACE foo AS /path/to/wherever". Yes,I think 'tablespace -> directory' is the most natural extension under current file_per_table storage manager. If many_tables_in_a_file storage manager is introduced,we may be able to change the definiiton of TABLESPACE to 'tablespace -> files' like Oracle. > That would make > appropriate system catalog entries and also create a symlink > from ".../data/base/foo" (or some such place) to the target > directory. > Then when we make a table in that tablespace, > it's in the right place. Problem solved, no? > I don't like symlink for dbms data files. However it may be OK,If symlink are limited to 'tablespace->directory' corrspondence and all tablespaces(including default etc) are symlink. It is simple and all debugging would be processed under tablespace_is_symlink environment. > It gets a little trickier if you want to be able to split > multi-gig tables across several tablespaces, though, since > you couldn't just append ".N" to the base table path in that > scenario. > This seems to be not that easy to solve now. Ross doesn't change this naming rule for multi-gig tables either in his trial. > I'd be interested to know what sort of facilities Oracle > provides for managing huge tables... > In my knowledge about old Oracle,one TABLESPACE could have many DATAFILEs which could contain many tables. Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3469@hub.org Fri Jun 16 02:01:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA08109 for ; Fri, 16 Jun 2000 02:01:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA11218 for ; Fri, 16 Jun 2000 01:57:33 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5G5tLI49492; Fri, 16 Jun 2000 01:55:21 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5G5tAI49395 for ; Fri, 16 Jun 2000 01:55:10 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id BAA05749; Fri, 16 Jun 2000 01:54:46 -0400 (EDT) To: "Hiroshi Inoue" cc: "PostgreSQL-development" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <000501bfd747$067f0220$2801007e@tpf.co.jp> References: <000501bfd747$067f0220$2801007e@tpf.co.jp> Comments: In-reply-to "Hiroshi Inoue" message dated "Fri, 16 Jun 2000 12:57:44 +0900" Date: Fri, 16 Jun 2000 01:54:46 -0400 Message-ID: <5746.961134886@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Hiroshi Inoue" writes: >> Why is a unique ID better than --- or even different from --- >> using the relation's OID? It seems pointless to me... > For example,in the implementation of CLUSTER command, > we would need another new file for the target relation in > order to put sorted rows but don't we want to change the > OID ? It would be needed for table re-construction generally. > If I remember correectly,you once proposed OID+version > naming for the cases. Hmm, so you are thinking that the pg_class row for the table would include this uniqueID, and then committing the pg_class update would be the atomic action that replaces the old table contents with the new? It does have some attraction now that I think about it. But there are other ways we could do the same thing. If we want to have tablespaces, there will need to be a tablespace identifier in each pg_class row. So we could do CLUSTER in the same way as we'd move a table from one tablespace to another: create the new files in the new tablespace directory, and the commit of the new pg_class row with the new tablespace value is the atomic action that makes the new files valid and the old files not. You will probably say "but I didn't want to move my table to a new tablespace just to cluster it!" I think we could live with that, though. A tablespace doesn't need to have any existence more concrete than a subdirectory, in my vision of the way things would work. We could do something like making two subdirectories of each place that the dbadmin designates as a "tablespace", so that we make two logical tablespaces out of what the dbadmin thinks of as one. Then we can ping-pong between those directories to do things like clustering "in place". Basically I want to keep the bottom-level mechanisms as simple and reliable as we possibly can. The fewer concepts are known down at the bottom, the better. If we can keep the pathname constituents to just "tablespace" and "relation OID" we'll be in great shape --- but each additional concept that has to be known down there is another potential problem. regards, tom lane From pgsql-hackers-owner+M3471@hub.org Fri Jun 16 03:31:05 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA12816 for ; Fri, 16 Jun 2000 03:31:04 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA14405 for ; Fri, 16 Jun 2000 03:03:38 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5G71YI83633; Fri, 16 Jun 2000 03:01:34 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5G713I82023 for ; Fri, 16 Jun 2000 03:01:04 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id QAA07731; Fri, 16 Jun 2000 16:00:57 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "PostgreSQL-development" Subject: RE: [HACKERS] Big 7.1 open items Date: Fri, 16 Jun 2000 16:03:06 +0900 Message-ID: <000101bfd760$ebcee3e0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <5746.961134886@sss.pgh.pa.us> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > "Hiroshi Inoue" writes: > >> Why is a unique ID better than --- or even different from --- > >> using the relation's OID? It seems pointless to me... > > > For example,in the implementation of CLUSTER command, > > we would need another new file for the target relation in > > order to put sorted rows but don't we want to change the > > OID ? It would be needed for table re-construction generally. > > If I remember correectly,you once proposed OID+version > > naming for the cases. > > Hmm, so you are thinking that the pg_class row for the table would > include this uniqueID, No,I just include the place where the table is stored(pathname under current file_per_table storage manager) in the pg_class row because I don't want to rely on table allocating rule(naming rule for current) to access existent relation files. This has always been my main point. Many_tables_in_a_file storage manager wouldn't be able to live without keeping this kind of infomation. This information(where it is stored) is diffrent from tablespace(where to store) information. There was an idea to keep the information into opaque entry in pg_class which only a specific storage manager could handle. There was an idea to have a new system table which keeps the information. and so on... > and then committing the pg_class update would > be the atomic action that replaces the old table contents with the > new? It does have some attraction now that I think about it. > > But there are other ways we could do the same thing. If we want to > have tablespaces, there will need to be a tablespace identifier in > each pg_class row. So we could do CLUSTER in the same way as we'd > move a table from one tablespace to another: create the new files in > the new tablespace directory, and the commit of the new pg_class row > with the new tablespace value is the atomic action that makes the new > files valid and the old files not. > > You will probably say "but I didn't want to move my table to a new > tablespace just to cluster it!" Yes. > I think we could live with that, > though. A tablespace doesn't need to have any existence more concrete > than a subdirectory, in my vision of the way things would work. We > could do something like making two subdirectories of each place that > the dbadmin designates as a "tablespace", so that we make two logical > tablespaces out of what the dbadmin thinks of as one. Certainly we could design TABLESPACE(where to store) as above. > Then we can > ping-pong between those directories to do things like clustering "in > place". > But maybe we must keep the directory information where the table was *ping-ponged* in (e.g.) pg_class. Is such an implementation cleaner or more extensible than mine(keeping the stored place exactly) ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3473@hub.org Fri Jun 16 04:01:12 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA13087 for ; Fri, 16 Jun 2000 04:01:11 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA16002 for ; Fri, 16 Jun 2000 03:37:24 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5G7ZZI51521; Fri, 16 Jun 2000 03:35:35 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5G7ZEI51350 for ; Fri, 16 Jun 2000 03:35:14 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id DAA06103; Fri, 16 Jun 2000 03:34:47 -0400 (EDT) To: Chris Bitmead cc: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <3949BCC4.8424A58F@nimrod.itg.telecom.com.au> References: <200006142043.WAA07887@hot.jw.home> <16606.961034835@sss.pgh.pa.us> <3949BCC4.8424A58F@nimrod.itg.telecom.com.au> Comments: In-reply-to Chris Bitmead message dated "Fri, 16 Jun 2000 15:36:04 +1000" Date: Fri, 16 Jun 2000 03:34:47 -0400 Message-ID: <6100.961140887@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Chris Bitmead writes: > Tom Lane wrote: >> I don't see a lot of value in that. Better to do something like >> tablespaces: >> >> // > What is the benefit of having oidoftablespace in the directory path? > Isn't tablespace an idea so you can store it somewhere completely > different? > Or is there some symlink idea or something? Exactly --- I'm assuming that the tablespace "directory" is likely to be a symlink to some other mounted volume. The point here is to keep the low-level file access routines from having to know very much about tablespaces or file organization. In the above proposal, all they need to know is the relation's OID and the name (or OID) of the tablespace the relation's assigned to; then they can form a valid path using a hardwired rule. There's still plenty of flexibility of organization, but it's not necessary to know that where the rubber meets the road (eg, when you're down inside mdblindwrt trying to dump a dirty buffer to disk with no spare resources to find out anything about the relation the page belongs to...) regards, tom lane From JanWieck@t-online.de Fri Jun 16 11:01:06 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA28913 for ; Fri, 16 Jun 2000 11:01:05 -0400 (EDT) Received: from mailout05.sul.t-online.com (mailout05.sul.t-online.com [194.25.134.82]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id KAA01818 for ; Fri, 16 Jun 2000 10:46:42 -0400 (EDT) Received: from fwd06.sul.t-online.de by mailout05.sul.t-online.com with smtp id 132xN9-0006ze-03; Fri, 16 Jun 2000 16:45:27 +0200 Received: from hot.jw.home (340000654369-0001@[62.158.179.251]) by fwd06.sul.t-online.de with esmtp id 132xMx-0E54HQC; Fri, 16 Jun 2000 16:45:15 +0200 Received: (from wieck@localhost) by hot.jw.home (8.8.5/8.8.5) id OAA15163; Fri, 16 Jun 2000 14:42:12 +0200 From: JanWieck@t-online.de (Jan Wieck) Message-Id: <200006161242.OAA15163@hot.jw.home> Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <3238.961126521@sss.pgh.pa.us> from Tom Lane at "Jun 15, 2000 11:35:21 pm" To: Tom Lane Date: Fri, 16 Jun 2000 14:42:12 +0200 (MEST) CC: Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Reply-To: Jan Wieck X-Mailer: ELM [version 2.4ME+ PL68 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Sender: 340000654369-0001@t-dialin.net Status: ROr Tom Lane wrote: > > It gets a little trickier if you want to be able to split > multi-gig tables across several tablespaces, though, since > you couldn't just append ".N" to the base table path in that > scenario. > > I'd be interested to know what sort of facilities Oracle > provides for managing huge tables... Oracle tablespaces are a collection of 1...n preallocated files. Each table then is bound to a tablespace and allocates extents (chunks) from those files. There are some per table attributes that control the extent sizes with default values coming from the tablespace. The initial extent size, the nextextent and the pctincrease. There is a hardcoded limit for the number of extents a table can have at all. In Oracle7 it was 512 (or somewhat below - don't recall correct). Maybe that's gone with Oracle8, don't know. This storage concept has IMHO a couple of advatages over ours. The tablespace files are preallocated, so there will never be a change in block allocation during runtime and that's the base for fdatasync() beeing sufficient at syncpoints. All what might be inaccurate after a crash is the last modified time in the inode, and that's totally irrelevant for Oracle. The fsck will never fail, and anything is up to Oracle's recovery. The number of total tablespace files is limited to a value that ensures, that the backends can keep them all open all the time. It's hard to exceed that limit. A typical SAP installation with more than 20,000 tables/indices doesn't need more than 30 or 40 of them. It is perfectly prepared for raw devices, since a tablespace in a raw device installation is simply an area of blocks on a disk. There are also disadvantages. You can run out of space even if there are plenty GB's free on your disks. You have to create tablespaces explicitly. If you've choosen inadequate extent size parameters, you end up with high fragmented tables (slowing down) or get stuck with running against maxextents, where only a reorg (export/import) helps. Jan -- #======================================================================# # It's easier to get forgiveness for being wrong than for being right. # # Let's break this rule - forgive me. # #================================================== JanWieck@Yahoo.com # From tgl@sss.pgh.pa.us Fri Jun 16 11:00:40 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA28898 for ; Fri, 16 Jun 2000 11:00:39 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id LAA07184; Fri, 16 Jun 2000 11:00:35 -0400 (EDT) To: Jan Wieck cc: Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006161242.OAA15163@hot.jw.home> References: <200006161242.OAA15163@hot.jw.home> Comments: In-reply-to JanWieck@t-online.de (Jan Wieck) message dated "Fri, 16 Jun 2000 14:42:12 +0200" Date: Fri, 16 Jun 2000 11:00:35 -0400 Message-ID: <7181.961167635@sss.pgh.pa.us> From: Tom Lane Status: RO JanWieck@t-online.de (Jan Wieck) writes: > There are also disadvantages. > You can run out of space even if there are plenty GB's > free on your disks. You have to create tablespaces > explicitly. Not to mention the reverse: if I read this right, you have to suck up your GB's long in advance of actually needing them. That's OK for a machine that's dedicated to Oracle ... not so OK for smaller installations, playpens, etc. I'm not convinced that there's anything fundamentally wrong with doing storage allocation in Unix files the way we have been. (At least not when we're sitting atop a well-done filesystem, which may leave the Linux folk out in the cold ;-).) regards, tom lane From tgl@sss.pgh.pa.us Fri Jun 16 12:01:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA29853 for ; Fri, 16 Jun 2000 12:01:02 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id LAA08255 for ; Fri, 16 Jun 2000 11:48:10 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id LAA07461; Fri, 16 Jun 2000 11:46:41 -0400 (EDT) To: Jan Wieck cc: Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006161242.OAA15163@hot.jw.home> References: <200006161242.OAA15163@hot.jw.home> Comments: In-reply-to JanWieck@t-online.de (Jan Wieck) message dated "Fri, 16 Jun 2000 14:42:12 +0200" Date: Fri, 16 Jun 2000 11:46:41 -0400 Message-ID: <7458.961170401@sss.pgh.pa.us> From: Tom Lane Status: RO JanWieck@t-online.de (Jan Wieck) writes: > Tom Lane wrote: >> It gets a little trickier if you want to be able to split >> multi-gig tables across several tablespaces, though, since >> you couldn't just append ".N" to the base table path in that >> scenario. >> >> I'd be interested to know what sort of facilities Oracle >> provides for managing huge tables... > Oracle tablespaces are a collection of 1...n preallocated > files. Each table then is bound to a tablespace and > allocates extents (chunks) from those files. OK, to get back to the point here: so in Oracle, tables can't cross tablespace boundaries, but a tablespace itself could span multiple disks? Not sure if I like that better or worse than equating a tablespace with a directory (so, presumably, all the files within it live on one filesystem) and then trying to make tables able to span tablespaces. We will need to do one or the other though, if we want to have any significant improvement over the current state of affairs for large tables. One way is to play the flip-the-path-ordering game some more, and access multiple-segment tables with pathnames like this: .../TABLESPACE/RELATION -- first or only segment .../TABLESPACE/N/RELATION -- N'th extension segment This isn't any harder for md.c to deal with than what we do now, but by making the /N subdirectories be symlinks, the dbadmin could easily arrange for extension segments to go on different filesystems. Also, since /N subdirectory symlinks can be added as needed, expanding available space by attaching more disks isn't hard. (If the admin hasn't pre-made a /N symlink when it's needed, I'd envision the backend just automatically creating a plain subdirectory so that it can extend the table.) A limitation is that the N'th extension segments of all the relations in a given tablespace have to be in the same place, but I don't see that as a major objection. Worst case is you make a separate tablespace for each of your multi-gig relations ... you're probably not going to have a very large number of such relations, so this doesn't seem like unmanageable admin complexity. We'd still want to create some tools to help the dbadmin with slinging all these symlinks around, of course. But I think it's critical to keep the low-level file access protocol simple and reliable, which really means minimizing the amount of information the backend needs to know to figure out which file to write a page in. With something like the above you only need to know the tablespace name (or more likely OID), the relation OID (+name or not, depending on outcome of other argument), and the offset in the table. No worse than now from the software's point of view. Comments? regards, tom lane From lockhart@alumni.caltech.edu Fri Jun 16 12:31:50 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA00649 for ; Fri, 16 Jun 2000 12:31:49 -0400 (EDT) Received: from huey.jpl.nasa.gov (huey.jpl.nasa.gov [128.149.68.100]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA13118 for ; Fri, 16 Jun 2000 12:31:52 -0400 (EDT) Received: from golem.jpl.nasa.gov (hectic-1 [128.149.68.203]) by huey.jpl.nasa.gov (8.8.8+Sun/8.8.8) with ESMTP id JAA15007; Fri, 16 Jun 2000 09:27:18 -0700 (PDT) Received: from alumni.caltech.edu (localhost.localdomain [127.0.0.1]) by golem.jpl.nasa.gov (Postfix) with ESMTP id DD8426F51; Fri, 16 Jun 2000 16:27:22 +0000 (UTC) Sender: lockhart@mythos.jpl.nasa.gov Message-ID: <394A556A.4EAC8B9A@alumni.caltech.edu> Date: Fri, 16 Jun 2000 16:27:22 +0000 From: Thomas Lockhart Organization: Yes X-Mailer: Mozilla 4.7 [en] (X11; I; Linux 2.2.14-15mdksmp i686) X-Accept-Language: en MIME-Version: 1.0 To: Tom Lane Cc: Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <200006161242.OAA15163@hot.jw.home> <7458.961170401@sss.pgh.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: RO > ... But I think it's critical to keep > the low-level file access protocol simple and reliable, which really > means minimizing the amount of information the backend needs to know > to figure out which file to write a page in. With something like the > above you only need to know the tablespace name (or more likely OID), > the relation OID (+name or not, depending on outcome of other > argument), and the offset in the table. No worse than now from the > software's point of view. > Comments? I'm probably missing the context a bit, but imho we should try hard to stay away from symlinks as the general solution for anything. Sorry for being behind here, but to make sure I'm on the right page: o tablespaces decouple storage from logical tables o a database lives in a default tablespace, unless specified o by default, a table will live in the default tablespace o (eventually) a table can be split across tablespaces Some thoughts: o the ability to split single tables across disks was essential for scalability when disks were small. But with RAID, NAS, etc etc isn't that a smaller issue now? o "tablespaces" would implement our less-developed "with location" feature, right? Splitting databases, whole indices and whole tables across storage is the biggest win for this work since more users will use the feature. o location information needs to travel with individual tables anyway. From scrappy@hub.org Fri Jun 16 13:01:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA01191; Fri, 16 Jun 2000 13:01:01 -0400 (EDT) Received: from thelab.hub.org (nat193.152.mpoweredpc.net [142.177.193.152]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA15282; Fri, 16 Jun 2000 12:53:23 -0400 (EDT) Received: from localhost (scrappy@localhost) by thelab.hub.org (8.9.3/8.9.3) with ESMTP id NAA28326; Fri, 16 Jun 2000 13:50:37 -0300 (ADT) (envelope-from scrappy@hub.org) X-Authentication-Warning: thelab.hub.org: scrappy owned process doing -bs Date: Fri, 16 Jun 2000 13:50:37 -0300 (ADT) From: The Hermit Hacker To: Bruce Momjian cc: Tom Lane , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <200006160224.WAA04345@candle.pha.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO On Thu, 15 Jun 2000, Bruce Momjian wrote: > > "Hiroshi Inoue" writes: > > > Now I like neither relname nor oid because it's not sufficient > > > for my purpose. > > > > We should probably not do much of anything with this issue until > > we have a clearer understanding of what we want to do about > > tablespaces and schemas. > > Here is an analysis of our options: > > Work required Disadvantages > ---------------------------------------------------------------------------- > > Keep current system no work rename/create no rollback > > relname/oid but less work new pg_class column, > no rename change filename not accurate on > rename > > relname/oid with more work complex code > rename change during > vacuum > > oid filename less work, but confusing to admins > need admin tools My vote is with Tom on this one ... oid only ... the admin should be able to do a quick SELECT on a table to find out the OID->table mapping, and I believe its already been pointed out that you cant' just restore one file anyway, so it kinda negates the "server isn't running problem" ... From tgl@sss.pgh.pa.us Fri Jun 16 13:01:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA01188 for ; Fri, 16 Jun 2000 13:01:01 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA15530 for ; Fri, 16 Jun 2000 12:55:38 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA07750; Fri, 16 Jun 2000 12:54:00 -0400 (EDT) To: Thomas Lockhart cc: Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <394A556A.4EAC8B9A@alumni.caltech.edu> References: <200006161242.OAA15163@hot.jw.home> <7458.961170401@sss.pgh.pa.us> <394A556A.4EAC8B9A@alumni.caltech.edu> Comments: In-reply-to Thomas Lockhart message dated "Fri, 16 Jun 2000 16:27:22 -0000" Date: Fri, 16 Jun 2000 12:54:00 -0400 Message-ID: <7747.961174440@sss.pgh.pa.us> From: Tom Lane Status: RO Thomas Lockhart writes: >> ... But I think it's critical to keep >> the low-level file access protocol simple and reliable, which really >> means minimizing the amount of information the backend needs to know >> to figure out which file to write a page in. With something like the >> above you only need to know the tablespace name (or more likely OID), >> the relation OID (+name or not, depending on outcome of other >> argument), and the offset in the table. No worse than now from the >> software's point of view. >> Comments? > I'm probably missing the context a bit, but imho we should try hard to > stay away from symlinks as the general solution for anything. Why? regards, tom lane From dhogaza@pacifier.com Fri Jun 16 14:55:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA02086 for ; Fri, 16 Jun 2000 14:54:59 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id OAA26430 for ; Fri, 16 Jun 2000 14:40:00 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id LAA08661; Fri, 16 Jun 2000 11:38:36 -0700 (PDT) Message-Id: <3.0.1.32.20000616105023.011dbdb0@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Fri, 16 Jun 2000 10:50:23 -0700 To: Tom Lane , Jan Wieck From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" In-Reply-To: <7458.961170401@sss.pgh.pa.us> References: <200006161242.OAA15163@hot.jw.home> <200006161242.OAA15163@hot.jw.home> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 11:46 AM 6/16/00 -0400, Tom Lane wrote: >OK, to get back to the point here: so in Oracle, tables can't cross >tablespace boundaries, Right, the construct AFAIK is "create table/index foo on tablespace ..." > but a tablespace itself could span multiple >disks? Right. >Not sure if I like that better or worse than equating a tablespace >with a directory (so, presumably, all the files within it live on >one filesystem) and then trying to make tables able to span >tablespaces. We will need to do one or the other though, if we want >to have any significant improvement over the current state of affairs >for large tables. Oracle's way does a reasonable job of isolating the datamodel from the details of the physical layout. Take the OpenACS web toolkit, for instance. We could take each module's tables and indices and assign them appropriately to various dataspaces, then provide a separate .sql files with only "create tablespace" statements in there. By modifying that one central file, the toolkit installation could be customized to run anything from a small site (one disk with everything on it, ala my own personal webserver at birdnotes.net) or a very large site with many spindles, with various index and table structures spread out widely hither and thither. Given that the OpenACS datamodel is nearly 10K lines long (including many comments, of course), being able to customize an installation to such a degree by modifying a single file filled with "create tablespaces" would be very attractive. >One way is to play the flip-the-path-ordering game some more, >and access multiple-segment tables with pathnames like this: > > .../TABLESPACE/RELATION -- first or only segment > .../TABLESPACE/N/RELATION -- N'th extension segment > >This isn't any harder for md.c to deal with than what we do now, >but by making the /N subdirectories be symlinks, the dbadmin could >easily arrange for extension segments to go on different filesystems. I personally dislike depending on symlinks to move stuff around. Among other things, a pg_dump/restore (and presumably future backup tools?) can't recreate the disk layout automatically. >We'd still want to create some tools to help the dbadmin with slinging >all these symlinks around, of course. OK, if symlinks are simply an implementation detail hidden from the dbadmin, and if the physical structure is kept in the db so it can be rebuilt if necessary automatically, then I don't mind symlinks. > But I think it's critical to keep >the low-level file access protocol simple and reliable, which really >means minimizing the amount of information the backend needs to know to >figure out which file to write a page in. With something like the above >you only need to know the tablespace name (or more likely OID), the >relation OID (+name or not, depending on outcome of other argument), >and the offset in the table. No worse than now from the software's >point of view. Make the code that creates and otherwise manipulates tablespaces do the work, while keeping the low-level file access protocol simple. Yes, this approach sounds very good to me. - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From pgsql-hackers-owner+M3500@hub.org Fri Jun 16 14:55:10 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA02107 for ; Fri, 16 Jun 2000 14:55:09 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id OAA26943 for ; Fri, 16 Jun 2000 14:44:12 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5GIelM05972; Fri, 16 Jun 2000 14:40:47 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by hub.org (8.10.1/8.10.1) with ESMTP id e5GIe5M05692 for ; Fri, 16 Jun 2000 14:40:05 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id LAA08667; Fri, 16 Jun 2000 11:38:41 -0700 (PDT) Message-Id: <3.0.1.32.20000616111435.01a17a10@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Fri, 16 Jun 2000 11:14:35 -0700 To: Thomas Lockhart , Tom Lane From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" In-Reply-To: <394A556A.4EAC8B9A@alumni.caltech.edu> References: <200006161242.OAA15163@hot.jw.home> <7458.961170401@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO At 04:27 PM 6/16/00 +0000, Thomas Lockhart wrote: >Sorry for being behind here, but to make sure I'm on the right page: >o tablespaces decouple storage from logical tables >o a database lives in a default tablespace, unless specified >o by default, a table will live in the default tablespace >o (eventually) a table can be split across tablespaces Or tablespaces across filesystems/mountpoints whatever. >Some thoughts: >o the ability to split single tables across disks was essential for >scalability when disks were small. But with RAID, NAS, etc etc isn't >that a smaller issue now? Yes for size issues, I should think, especially if you have the money for a large RAID subsystem. But for throughput performance, control over which spindles particularly busy tables and indices go on would still seem to be pretty relevant, when they're being updated a lot. In order to minimize seek times. I really can't say how important this is in reality. Oracle-world folks still talk about this kind of optimization being important, but I'm not personally running any kind of database-backed website that's busy enough or contains enough storage to worry about it. >o "tablespaces" would implement our less-developed "with location" >feature, right? Splitting databases, whole indices and whole tables >across storage is the biggest win for this work since more users will >use the feature. >o location information needs to travel with individual tables anyway. - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From tgl@sss.pgh.pa.us Fri Jun 16 15:00:55 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id PAA02397 for ; Fri, 16 Jun 2000 15:00:54 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id PAA08247; Fri, 16 Jun 2000 15:00:11 -0400 (EDT) To: Don Baccus cc: Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <3.0.1.32.20000616105023.011dbdb0@mail.pacifier.com> References: <200006161242.OAA15163@hot.jw.home> <200006161242.OAA15163@hot.jw.home> <3.0.1.32.20000616105023.011dbdb0@mail.pacifier.com> Comments: In-reply-to Don Baccus message dated "Fri, 16 Jun 2000 10:50:23 -0700" Date: Fri, 16 Jun 2000 15:00:10 -0400 Message-ID: <8244.961182010@sss.pgh.pa.us> From: Tom Lane Status: RO Don Baccus writes: >> This isn't any harder for md.c to deal with than what we do now, >> but by making the /N subdirectories be symlinks, the dbadmin could >> easily arrange for extension segments to go on different filesystems. > I personally dislike depending on symlinks to move stuff around. > Among other things, a pg_dump/restore (and presumably future > backup tools?) can't recreate the disk layout automatically. Good point, we'd need some way of saving/restoring the tablespace structures. >> We'd still want to create some tools to help the dbadmin with slinging >> all these symlinks around, of course. > OK, if symlinks are simply an implementation detail hidden from the > dbadmin, and if the physical structure is kept in the db so it can > be rebuilt if necessary automatically, then I don't mind symlinks. I'm not sure about keeping it in the db --- creates a bit of a chicken-and-egg problem doesn't it? Maybe there needs to be a "system database" that has nailed-down pathnames (no tablespaces for you baby) and contains the critical installation-wide tables like pg_database, pg_user, pg_tablespace. A restore would have to restore these tables first anyway. > Make the code that creates and otherwise manipulates tablespaces > do the work, while keeping the low-level file access protocol simple. Right, that's the bottom line for me. regards, tom lane From reedstrm@rice.edu Fri Jun 16 16:51:50 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id QAA03689 for ; Fri, 16 Jun 2000 16:51:49 -0400 (EDT) Received: from wallace.ece.rice.edu (wallace.ece.rice.edu [128.42.12.154]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id PAA03409 for ; Fri, 16 Jun 2000 15:48:40 -0400 (EDT) Received: by rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for maillist@candle.pha.pa.us; Fri, 16 Jun 2000 14:35:28 -0500 (CDT) Date: Fri, 16 Jun 2000 14:35:28 -0500 From: "Ross J. Reedstrom" To: Thomas Lockhart Cc: Tom Lane , Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items Message-ID: <20000616143528.A28920@rice.edu> Mail-Followup-To: Thomas Lockhart , Tom Lane , Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development References: <200006161242.OAA15163@hot.jw.home> <7458.961170401@sss.pgh.pa.us> <394A556A.4EAC8B9A@alumni.caltech.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.0i In-Reply-To: <394A556A.4EAC8B9A@alumni.caltech.edu>; from lockhart@alumni.caltech.edu on Fri, Jun 16, 2000 at 04:27:22PM +0000 Status: RO On Fri, Jun 16, 2000 at 04:27:22PM +0000, Thomas Lockhart wrote: > > ... But I think it's critical to keep > > the low-level file access protocol simple and reliable, which really > > means minimizing the amount of information the backend needs to know > > to figure out which file to write a page in. With something like the > > above you only need to know the tablespace name (or more likely OID), > > the relation OID (+name or not, depending on outcome of other > > argument), and the offset in the table. No worse than now from the > > software's point of view. > > Comments? I think the backend needs a per table token that indicates how to get at the physical bits of the file. Whether that's a filename alone, filename with path, oid, key to a smgr hash table or something else, it's opaque above the smgr routines. Hmm, now I'm thinking, since the tablespace discussion has been reopened, the way to go about coding all this is to reactivate the smgr code: how about I leave the existing md smgr as is, and clone it, call it md2 or something, and start messing with adding features there? > > I'm probably missing the context a bit, but imho we should try hard to > stay away from symlinks as the general solution for anything. > > Sorry for being behind here, but to make sure I'm on the right page: > o tablespaces decouple storage from logical tables > o a database lives in a default tablespace, unless specified > o by default, a table will live in the default tablespace > o (eventually) a table can be split across tablespaces > > Some thoughts: > o the ability to split single tables across disks was essential for > scalability when disks were small. But with RAID, NAS, etc etc isn't > that a smaller issue now? > o "tablespaces" would implement our less-developed "with location" > feature, right? Splitting databases, whole indices and whole tables > across storage is the biggest win for this work since more users will > use the feature. > o location information needs to travel with individual tables anyway. I was juist thinking that that discussion needed some summation. Some links to historic discussion: This one is Vadim saying WAL will need oids names: http://www.postgresql.org/mhonarc/pgsql-hackers/1999-11/msg00809.html A longer discussion kicked off by Don Baccus: http://www.postgresql.org/mhonarc/pgsql-hackers/2000-01/msg00510.html Tom suggesting OIDs to allow rollback: http://www.postgresql.org/mhonarc/pgsql-hackers/2000-03/msg00119.html Martin Neumann posted an question on dataspaces: (can't find it in the offical archives: looks like March 2000, 10-29 is missing. here's my copy: don't beat on it! n particular, since I threw it together for local access, it's one _big_ index page) http://cooker.ir.rice.edu/postgresql/msg20257.html (in that thread is a post where I mention blindwrites and getting rid of GetRawDatabaseInfo) Martin later posted an RFD on tablespaces: http://cooker.ir.rice.edu/postgresql/msg20490.html Here's Horák Daniel with a patch for discussion, implementing dataspaces on a per database level: http://cooker.ir.rice.edu/postgresql/msg20498.html Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 From dhogaza@pacifier.com Fri Jun 16 16:51:51 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id QAA03692 for ; Fri, 16 Jun 2000 16:51:50 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id PAA02911 for ; Fri, 16 Jun 2000 15:43:13 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id MAA11003; Fri, 16 Jun 2000 12:41:50 -0700 (PDT) Message-Id: <3.0.1.32.20000616123736.01a19910@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Fri, 16 Jun 2000 12:37:36 -0700 To: Tom Lane From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" In-Reply-To: <8244.961182010@sss.pgh.pa.us> References: <3.0.1.32.20000616105023.011dbdb0@mail.pacifier.com> <200006161242.OAA15163@hot.jw.home> <200006161242.OAA15163@hot.jw.home> <3.0.1.32.20000616105023.011dbdb0@mail.pacifier.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 03:00 PM 6/16/00 -0400, Tom Lane wrote: >> OK, if symlinks are simply an implementation detail hidden from the >> dbadmin, and if the physical structure is kept in the db so it can >> be rebuilt if necessary automatically, then I don't mind symlinks. > >I'm not sure about keeping it in the db --- creates a bit of a >chicken-and-egg problem doesn't it? Not if the tablespace creates preceeds the tables stored in them. > Maybe there needs to be a >"system database" that has nailed-down pathnames (no tablespaces >for you baby) and contains the critical installation-wide tables >like pg_database, pg_user, pg_tablespace. A restore would have >to restore these tables first anyway. Oh, I see. Yes, when I've looked into this and have thought about it I've assumed that there would always be a known starting point which would contain the installation-wide tables. >From a practical point of view, I don't think that's really a problem. I've not looked into how Oracle does this, I assume it builds a system tablespace on one of the initial mount points you give it when you install the thing. The paths to the mount points are stored in specific files known to Oracle, I think. It's been over a year (not long enough!) since I've set up Oracle... - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From pgsql-hackers-owner+M3512@hub.org Fri Jun 16 17:31:04 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA04168 for ; Fri, 16 Jun 2000 17:31:03 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id RAA12122 for ; Fri, 16 Jun 2000 17:09:28 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5GL7WM02231; Fri, 16 Jun 2000 17:07:32 -0400 (EDT) Received: from wallace.ece.rice.edu (wallace.ece.rice.edu [128.42.12.154]) by hub.org (8.10.1/8.10.1) with ESMTP id e5GL7EM02150 for ; Fri, 16 Jun 2000 17:07:14 -0400 (EDT) Received: by rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for pgsql-hackers@postgresql.org; Fri, 16 Jun 2000 16:07:13 -0500 (CDT) Date: Fri, 16 Jun 2000 16:07:13 -0500 From: "Ross J. Reedstrom" To: Tom Lane Cc: pgsql-hackers@postgresql.org Subject: Re: [HACKERS] Big 7.1 open items Message-ID: <20000616160713.A30793@rice.edu> Mail-Followup-To: Tom Lane , pgsql-hackers@postgresql.org References: <16985.961038832@sss.pgh.pa.us> <200006150321.XAA09510@candle.pha.pa.us> <20000615010312.A995@rice.edu> <18798.961053112@sss.pgh.pa.us> <20000615114519.B3939@rice.edu> <2260.961113232@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii User-Agent: Mutt/1.0i In-Reply-To: <2260.961113232@sss.pgh.pa.us>; from tgl@sss.pgh.pa.us on Thu, Jun 15, 2000 at 07:53:52PM -0400 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO On Thu, Jun 15, 2000 at 07:53:52PM -0400, Tom Lane wrote: > "Ross J. Reedstrom" writes: > > On Thu, Jun 15, 2000 at 03:11:52AM -0400, Tom Lane wrote: > >> "Ross J. Reedstrom" writes: > >>>> Any strong objections to the mixed relname_oid solution? > >> > >> Yes! > > > The plan here was to let VACUUM handle renaming the file, since it > > will already have all the necessary locks. This shortens the window > > of confusion. ALTER TABLE RENAME doesn't happen that often, really - > > the relname is there just for human consumption, then. > > Yeah, I've seen tons of discussion of how if we do this, that, and > the other thing, and be prepared to fix up some other things in case > of crash recovery, we can make it work with filename == relname + OID > (where relname tracks logical name, at least at some remove). > > Probably. Assuming nobody forgets anything. I agree, it seems a major undertaking, at first glance. And second. Even third. Especially for someone who hasn't 'earned his spurs' yet. as it were. > I'm just trying to point out that that's a huge amount of pretty > delicate mechanism. The amount of work required to make it trustworthy > looks to me to dwarf the admin tools that Bruce is complaining about. > And we only have a few people competent to do the work. (With all > due respect, Ross, if you weren't already aware of the implications > for mdblindwrt, I have to wonder what else you missed.) Ah, you knew that comment would come back to haunt me (I have a tendency to think out loud, even if checking and coming back latter would be better;-) In fact, there's no problem, and never was, since the buffer->blind.relname is filled in via RelationGetPhysicalRelationName, just like every other path that requires direct file access. I just didn't remember that I had in fact checked it (it's been a couple months, and I just got back from vacation ;-) Actually, Once I re-checked it, the code looked very familiar. I had spent time looking at the blind write code in the context of getting rid of the only non-startup use of GetRawDatabaseInfo. As to missing things: I'm leaning heavily on Bruce's previous work for temp tables, to seperate the two uses of relname, via the RelationGetRelationName and RelationGetPhysicalRelationName. There are 102 uses of the first in the current code (many in elog messages), and only 11 of the second. If I'd had to do the original work of finding every use of relname, and catagorizing it, I agree I'm not (yet) up to it, but I have more confidence in Bruce's (already tested) work. > > Filename == OID is so simple, reliable, and straightforward by > comparison that I think the decision is a no-brainer. > Perhaps. Changing the label of the file on disk still requires finding all the code that assumes it knows what that name is, and changing it. Same work. > If we could afford to sink unlimited time into this one issue then > it might make sense to do it the hard way, but we have enough > important stuff on our TODO list to keep us all busy for years --- > I cannot believe that it's an effective use of our time to do this. > The joys of Open Development. You've spent a fair amount of time trying to convince _me_ not to waste my time. Thanks, but I'm pretty bull headed sometimes. Since I've already done something of the work, take a look at what I've got, and then tell me I'm wasting my time, o.k.? > > > Hmm, what's all this with functions in catalog.c that are only called by > > smgr/md.c? seems to me that anything having to do with physical storage > > (like the path!) belongs in the smgr abstraction. > > Yeah, there's a bunch of stuff that should have been implemented by > adding new smgr entry points, but wasn't. It should be pushed down. > (I can't resist pointing out that one of those things is physical > relation rename, which will go away and not *need* to be pushed down > if we do it the way I want.) > Oh, I agree completely. In fact, As I said to Hiroshi last time this came up, I think of the field in pg_class an an opaque token, to be filled in by the smgr, and only used by code further up to hand back to the smgr routines. Same should be true of the buffer->blind struct. Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 From Inoue@tpf.co.jp Fri Jun 16 19:31:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA05334 for ; Fri, 16 Jun 2000 19:30:59 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA19834 for ; Fri, 16 Jun 2000 19:09:59 -0400 (EDT) Received: from mcadnote1 (ppm122.noc.fukui.nsk.ne.jp [210.161.188.41]) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id IAA08210; Sat, 17 Jun 2000 08:08:15 +0900 From: "Hiroshi Inoue" To: "Tom Lane" , "Jan Wieck" Cc: "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Sat, 17 Jun 2000 08:11:08 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) In-Reply-To: <7181.961167635@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Importance: Normal Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > JanWieck@t-online.de (Jan Wieck) writes: > > There are also disadvantages. > > > You can run out of space even if there are plenty GB's > > free on your disks. You have to create tablespaces > > explicitly. > > Not to mention the reverse: if I read this right, you have to suck > up your GB's long in advance of actually needing them. That's OK > for a machine that's dedicated to Oracle ... not so OK for smaller > installations, playpens, etc. > I've had an anxiety about the way like Oracle's preallocation. It had not been easy for me to estimate the extent size in Oracle. Maybe it would lose the simplicity of environment settings which is one of the biggest advantage of PostgreSQL. It seems that we should also provide not_preallocated DATAFILE when many_tables_in_a_file storage manager is introduced. Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Fri Jun 16 19:31:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA05337 for ; Fri, 16 Jun 2000 19:31:00 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA20335 for ; Fri, 16 Jun 2000 19:18:26 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id TAA09274; Fri, 16 Jun 2000 19:16:37 -0400 (EDT) To: "Ross J. Reedstrom" cc: Thomas Lockhart , Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <20000616143528.A28920@rice.edu> References: <200006161242.OAA15163@hot.jw.home> <7458.961170401@sss.pgh.pa.us> <394A556A.4EAC8B9A@alumni.caltech.edu> <20000616143528.A28920@rice.edu> Comments: In-reply-to "Ross J. Reedstrom" message dated "Fri, 16 Jun 2000 14:35:28 -0500" Date: Fri, 16 Jun 2000 19:16:37 -0400 Message-ID: <9271.961197397@sss.pgh.pa.us> From: Tom Lane Status: RO "Ross J. Reedstrom" writes: > I think the backend needs a per table token that indicates how > to get at the physical bits of the file. Whether that's a filename > alone, filename with path, oid, key to a smgr hash table or something > else, it's opaque above the smgr routines. Except to the commands that provide the user interface for tablespaces and so forth. And there aren't all that many places that deal with physical filenames anyway. It would be a good idea to try to be a little stricter about this, but I'm not sure you can make the separation a whole lot cleaner than it is now ... with the exception of the obvious bogosities like "rename table" being done above the smgr level. (But, as I said, I want to see that code go away, not just get moved into smgr...) > Hmm, now I'm thinking, since the tablespace discussion has been reopened, > the way to go about coding all this is to reactivate the smgr code: how > about I leave the existing md smgr as is, and clone it, call it md2 or > something, and start messing with adding features there? Um, well, you can't have it both ways. If you're going to change/fix the assumptions of code above the smgr, then you've got to update md at the same time to match your new definition of the smgr interface. Won't do much good to have a playpen smgr if the "standard" one is broken. One thing I have been thinking would be a good idea is to take the relcache out of the bufmgr/smgr interfaces. The relcache is a higher-level concept and ought not be known to bufmgr or smgr; they ought to work with some low-level data structure or token for relations. We might be able to eliminate the whole concept of "blind write" if we do that. There are other problems with the relcache dependency: entries in relcache can get blown away at inopportune times due to shared cache inval, and it doesn't provide a good home for tokens for multiple "versions" of a relation if we go with the fill-a-new-physical-file approach to CLUSTER and so on. Hmm, if you replace relcache in the smgr interfaces with pointers to an smgr-maintained data structure, that might be the same thing that you are alluding to above about an smgr hash table. One thing *not* to do is add yet a third layer of data structure on top of the ones already maintained in fd.c and md.c. Whatever extra data might be needed here should be added to md.c's tables, I think, and then the tokens used in the smgr interface would be pointers into that table. regards, tom lane From tgl@sss.pgh.pa.us Fri Jun 16 19:30:43 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA05329 for ; Fri, 16 Jun 2000 19:30:41 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id TAA09320; Fri, 16 Jun 2000 19:30:26 -0400 (EDT) To: "Hiroshi Inoue" cc: "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: References: Comments: In-reply-to "Hiroshi Inoue" message dated "Sat, 17 Jun 2000 08:11:08 +0900" Date: Fri, 16 Jun 2000 19:30:25 -0400 Message-ID: <9317.961198225@sss.pgh.pa.us> From: Tom Lane Status: ROr "Hiroshi Inoue" writes: > It seems that we should also provide not_preallocated DATAFILE > when many_tables_in_a_file storage manager is introduced. Several people in this thread have been talking like a single-physical-file storage manager is in our future, but I can't recall anyone saying that they were going to do such a thing or even presenting reasons why it'd be a good idea. Seems to me that physical file per relation is considerably better for our purposes. It's easier to figure out what's going on for admin and debug work, it means less lock contention among different backends appending concurrently to different relations, and it gives the OS a better shot at doing effective read-ahead on sequential scans. So why all the enthusiasm for multi-tables-per-file? regards, tom lane From chris@bitmead.com Fri Jun 16 21:01:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA07578; Fri, 16 Jun 2000 21:01:00 -0400 (EDT) Received: from tech.com.au (IDENT:root@techpt.lnk.telstra.net [139.130.75.122]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id UAA24724; Fri, 16 Jun 2000 20:39:30 -0400 (EDT) Received: from bitmead.com (IDENT:chris@tardis [203.41.180.243]) by tech.com.au (8.9.3/8.9.3) with ESMTP id KAA21388; Sat, 17 Jun 2000 10:39:21 +1000 Sender: chris@tech.com.au Message-ID: <394AC8B4.C5B4CCFB@bitmead.com> Date: Sat, 17 Jun 2000 10:39:16 +1000 From: Chris Bitmead X-Mailer: Mozilla 4.72 [en] (X11; U; Linux 2.2.14-5.0 i686) X-Accept-Language: en MIME-Version: 1.0 To: Bruce Momjian CC: Tom Lane , Hiroshi Inoue , Jan Wieck , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <200006170008.UAA06798@candle.pha.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: RO > > So why all the enthusiasm for multi-tables-per-file? It allows you to use raw partitions which stop the OS double buffering and wasting half of memory, as well as removing the overhead of indirect blocks in the file system. From Inoue@tpf.co.jp Sat Jun 17 06:00:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id GAA22177; Sat, 17 Jun 2000 06:00:59 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id FAA21759; Sat, 17 Jun 2000 05:36:27 -0400 (EDT) Received: from mcadnote1 (ppm130.noc.fukui.nsk.ne.jp [210.161.188.49]) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id SAA08383; Sat, 17 Jun 2000 18:35:36 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" , "Tom Lane" Cc: "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Sat, 17 Jun 2000 18:38:29 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) In-Reply-To: <200006170008.UAA06798@candle.pha.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Importance: Normal Status: RO > -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > > So why all the enthusiasm for multi-tables-per-file? > > No idea. I thought Vadim mentioned it, but I am not sure anymore. I > certainly like our current system. > Oops,I'm not so enthusiastic for multi_tables_per_file smgr. I believe that Ross and I have taken a practical way that doesn't break current file_per_table smgr. However it seems very natural to take multi_tables_per_file smgr into account when we consider TABLESPACE concept. Because TABLESPACE is an encapsulation,it should have a possibility to handle multi_tables_per_file smgr IMHO. Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Sat Jun 17 12:31:08 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA02794; Sat, 17 Jun 2000 12:31:07 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA07194; Sat, 17 Jun 2000 12:12:53 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA18824; Sat, 17 Jun 2000 12:11:18 -0400 (EDT) To: "Hiroshi Inoue" cc: "Bruce Momjian" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: References: Comments: In-reply-to "Hiroshi Inoue" message dated "Sat, 17 Jun 2000 18:38:29 +0900" Date: Sat, 17 Jun 2000 12:11:18 -0400 Message-ID: <18821.961258278@sss.pgh.pa.us> From: Tom Lane Status: RO "Hiroshi Inoue" writes: > However it seems very natural to take multi_tables_per_file > smgr into account when we consider TABLESPACE concept. > Because TABLESPACE is an encapsulation,it should have > a possibility to handle multi_tables_per_file smgr IMHO. OK, I see: you're just saying that the tablespace stuff should be designed in such a way that it would work with a non-file-per-table smgr. Agreed, that'd be a good check of a clean design, and someday we might need it... regards, tom lane From tgl@sss.pgh.pa.us Sun Jun 18 12:30:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA06514 for ; Sun, 18 Jun 2000 12:30:58 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA04979 for ; Sun, 18 Jun 2000 12:07:44 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA12163; Sun, 18 Jun 2000 12:06:29 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006181333.JAA01648@candle.pha.pa.us> References: <200006181333.JAA01648@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Sun, 18 Jun 2000 09:33:44 -0400" Date: Sun, 18 Jun 2000 12:06:29 -0400 Message-ID: <12160.961344389@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > ... We could even get fancy and > round-robin through all the extents directories, looping around to the > beginning when we run out of them. That sounds nice. That sounds horrible. There's no way to tell which extent directory extent N goes into except by scanning the location directory to find out how many extent subdirectories there are (so that you can compute N modulo number-of-directories). Do you want to pay that price on every file open? Worse, what happens when you add another extent directory? You can't find your old extents anymore, that's what, because they're not in the right place (N modulo number-of-directories just changed). Since the extents are presumably on different volumes, you're talking about physical file moves to get them where they should be. You probably can't add a new extent without shutting down the entire database while you reshuffle files --- at the very least you'd need to get exclusive locks on all the tables in that tablespace. Also, you'll get filename conflicts from multiple extents of a single table appearing in one of the recycled extent dirs. You could work around it by using the non-modulo'd N as part of the final file name, but that just adds more complexity and makes the filename-generation machinery that much more closely tied to this specific way of doing things. The right way to do this is that extent N goes into extents subdirectory N, period. If there's no such subdirectory, create one on-the-fly as a plain subdirectory of the location directory. The dbadmin can easily create secondary extent symlinks *in advance of their being needed*. Reorganizing later is much more painful since it requires moving physical files, but I think that'd be true no matter what. At least we should see to it that adding more space in advance of needing it is painless. It's possible to do it that way (auto-create extent subdir if needed) without tying the md.c machinery real closely to a specific filename creation procedure: it's just the same sort of thing as install programs customarily do. "If you fail to create a file, try creating its ancestor directory." We'd have to think about whether it'd be a good idea to allow auto-creation of more than one level of directory; offhand it seems that needing to make more than one level is probably a sign of an erroneous path, not need for another extent subdirectory. regards, tom lane From dhogaza@pacifier.com Sun Jun 18 20:01:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA19951 for ; Sun, 18 Jun 2000 20:00:59 -0400 (EDT) Received: from smtp.pacifier.com (asteroid.pacifier.com [199.2.117.154]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA24345 for ; Sun, 18 Jun 2000 19:50:06 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id QAA05302; Sun, 18 Jun 2000 16:49:27 -0700 (PDT) Message-Id: <3.0.1.32.20000618164342.011d2450@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Sun, 18 Jun 2000 16:43:42 -0700 To: Bruce Momjian , Tom Lane From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" In-Reply-To: <200006182250.SAA13436@candle.pha.pa.us> References: <12160.961344389@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: ROr At 06:50 PM 6/18/00 -0400, Bruce Momjian wrote: >If we eliminate the round-robin idea, what did people think of the rest >of the ideas? Why invent new syntax when "create tablespace" is something a lot of folks will recognize? And why not use "create table ... using ... "? In other words, Oracle-compatible for this construct? Sure, Postgres doesn't have to follow Oraclisms but picking an existing contruct means at least SOME folks can import a datamodel without having to edit it. Does your proposal break the smgr abstraction, i.e. does it preclude later efforts to (say) implement an (optional) raw-device storage manager? - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From pgsql-hackers-owner+M3571@hub.org Sun Jun 18 23:28:13 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA23880 for ; Sun, 18 Jun 2000 23:28:12 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id XAA04627 for ; Sun, 18 Jun 2000 23:24:37 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5J3GQM78526; Sun, 18 Jun 2000 23:16:26 -0400 (EDT) Received: from candle.pha.pa.us (pgman@nav-43.dsl.navpoint.com [162.33.245.46]) by hub.org (8.10.1/8.10.1) with ESMTP id e5J3E3M71538 for ; Sun, 18 Jun 2000 23:14:03 -0400 (EDT) Received: (from pgman@localhost) by candle.pha.pa.us (8.9.0/8.9.0) id XAA23541; Sun, 18 Jun 2000 23:13:44 -0400 (EDT) From: Bruce Momjian Message-Id: <200006190313.XAA23541@candle.pha.pa.us> Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <12160.961344389@sss.pgh.pa.us> "from Tom Lane at Jun 18, 2000 12:06:29 pm" To: Tom Lane Date: Sun, 18 Jun 2000 23:13:44 -0400 (EDT) CC: Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" X-Mailer: ELM [version 2.4ME+ PL77 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO My basic proposal is that we optionally allow symlinks when creating tablespace directories, and that we interrogate those symlinks during a dump so administrators can move tablespaces around without having to modify environment variables or system tables. I also suggested creating an extent directory to hold extents, like extent/2 and extent/3. This will allow administration for smaller sites to be simpler. -- Bruce Momjian | http://www.op.net/~candle pgman@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 From dhogaza@pacifier.com Mon Jun 19 00:31:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA01941 for ; Mon, 19 Jun 2000 00:31:00 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id AAA06881 for ; Mon, 19 Jun 2000 00:11:39 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id VAA29138; Sun, 18 Jun 2000 21:11:01 -0700 (PDT) Message-Id: <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Sun, 18 Jun 2000 21:07:48 -0700 To: Bruce Momjian , Tom Lane From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" In-Reply-To: <200006190313.XAA23541@candle.pha.pa.us> References: <12160.961344389@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 11:13 PM 6/18/00 -0400, Bruce Momjian wrote: >My basic proposal is that we optionally allow symlinks when creating >tablespace directories, and that we interrogate those symlinks during a >dump so administrators can move tablespaces around without having to >modify environment variables or system tables. If they can move them around from within the db, they'll have no need to move them around from outside the db. I don't quite understand your devotion to using filesystem commands outside the database to do database administration. - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From pgsql-hackers-owner+M3573@hub.org Mon Jun 19 01:31:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA01981 for ; Mon, 19 Jun 2000 01:31:01 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA09569 for ; Mon, 19 Jun 2000 01:13:53 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5J4T3M86960; Mon, 19 Jun 2000 00:29:04 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5J4RFM80712 for ; Mon, 19 Jun 2000 00:27:15 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id AAA09517; Mon, 19 Jun 2000 00:25:53 -0400 (EDT) To: Bruce Momjian cc: Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006190313.XAA23541@candle.pha.pa.us> References: <200006190313.XAA23541@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Sun, 18 Jun 2000 23:13:44 -0400" Date: Mon, 19 Jun 2000 00:25:52 -0400 Message-ID: <9514.961388752@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Bruce Momjian writes: > I also suggested creating an extent directory to hold extents, like > extent/2 and extent/3. This will allow administration for smaller sites > to be simpler. I don't see the value in creating an extra level of directory --- seems that just adds one more Unix directory-lookup cycle to each file open, without any apparent return. What's wrong with extent directory names like extent2, extent3, etc? Obviously the extent dirnames must be chosen so they can't conflict with table filenames, but that's easily done. For example, if table files are named like 'OID_xxx' then 'extentN' will never conflict. regards, tom lane From tgl@sss.pgh.pa.us Mon Jun 19 00:30:58 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA01934 for ; Mon, 19 Jun 2000 00:30:58 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id AAA07814 for ; Mon, 19 Jun 2000 00:29:36 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id AAA09535; Mon, 19 Jun 2000 00:28:14 -0400 (EDT) To: Don Baccus cc: Bruce Momjian , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> References: <12160.961344389@sss.pgh.pa.us> <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> Comments: In-reply-to Don Baccus message dated "Sun, 18 Jun 2000 21:07:48 -0700" Date: Mon, 19 Jun 2000 00:28:14 -0400 Message-ID: <9532.961388894@sss.pgh.pa.us> From: Tom Lane Status: ROr Don Baccus writes: > If they can move them around from within the db, they'll have no need to > move them around from outside the db. > I don't quite understand your devotion to using filesystem commands > outside the database to do database administration. Being *able* to use filesystem commands to see/fix what's going on is a good thing, particularly from a development/debugging standpoint. But I agree we want to have within-the-system admin commands to do the same things. regards, tom lane From pgsql-hackers-owner+M3574@hub.org Mon Jun 19 01:31:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA01977 for ; Mon, 19 Jun 2000 01:31:00 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA09374 for ; Mon, 19 Jun 2000 01:07:50 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5J4VkM95901; Mon, 19 Jun 2000 00:31:46 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5J4TgM89399 for ; Mon, 19 Jun 2000 00:29:42 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id AAA09535; Mon, 19 Jun 2000 00:28:14 -0400 (EDT) To: Don Baccus cc: Bruce Momjian , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> References: <12160.961344389@sss.pgh.pa.us> <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> Comments: In-reply-to Don Baccus message dated "Sun, 18 Jun 2000 21:07:48 -0700" Date: Mon, 19 Jun 2000 00:28:14 -0400 Message-ID: <9532.961388894@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Don Baccus writes: > If they can move them around from within the db, they'll have no need to > move them around from outside the db. > I don't quite understand your devotion to using filesystem commands > outside the database to do database administration. Being *able* to use filesystem commands to see/fix what's going on is a good thing, particularly from a development/debugging standpoint. But I agree we want to have within-the-system admin commands to do the same things. regards, tom lane From dhogaza@pacifier.com Mon Jun 19 00:58:39 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA00799 for ; Mon, 19 Jun 2000 00:58:38 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id AAA08143 for ; Mon, 19 Jun 2000 00:37:39 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id VAA00259; Sun, 18 Jun 2000 21:36:25 -0700 (PDT) Message-Id: <3.0.1.32.20000618213319.011d59c0@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Sun, 18 Jun 2000 21:33:19 -0700 To: Tom Lane From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: Bruce Momjian , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" In-Reply-To: <9532.961388894@sss.pgh.pa.us> References: <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> <12160.961344389@sss.pgh.pa.us> <3.0.1.32.20000618210748.011d1c40@mail.pacifier.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 12:28 AM 6/19/00 -0400, Tom Lane wrote: >Being *able* to use filesystem commands to see/fix what's going on is a >good thing, particularly from a development/debugging standpoint. Of course it's a crutch for development, but outside of development circles few users will know how to use the OS in regard to the database. Assuming PG takes off. Of course, if it remains the realm of the dedicated hard-core hacker, I'm wrong. I have nothing against preserving the ability to use filesystem commands if there's no significant costs inherent with this approach. I'd view the breaking of smgr abstraction as a significant cost (though I agree with Ross that it Bruce's proposal shouldn't require that, I asked my question to flush Bruce out, if you will, because he's devoted to a particular outside-the-db management model). > But >I agree we want to have within-the-system admin commands to do the same >things. MUST have, I should think. - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From Inoue@tpf.co.jp Mon Jun 19 12:31:17 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA29988 for ; Mon, 19 Jun 2000 12:31:16 -0400 (EDT) Received: from sd.tpf.co.jp (mail.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA21005 for ; Mon, 19 Jun 2000 12:15:22 -0400 (EDT) Received: from mcadnote1 (ppm127.noc.fukui.nsk.ne.jp [210.161.188.46]) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id BAA09828; Tue, 20 Jun 2000 01:14:19 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" Cc: "Tom Lane" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Don Baccus" Subject: RE: [HACKERS] Big 7.1 open items Date: Tue, 20 Jun 2000 01:17:14 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) In-Reply-To: <200006191330.JAA16908@candle.pha.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Importance: Normal Status: ROr > -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > The fact is that symlink information is already stored in the file > system. If we store symlink information in the database too, there > exists the ability for the two to get out of sync. My point is that I > think we can _not_ store symlink information in the database, and query > the file system using lstat when required. > Hmm,this seems pretty confusing to me. I don't understand the necessity of symlink. Directory tree,symlink,hard link ... are OS's standard. But I don't think they are fit for dbms management. PostgreSQL is a database system of cource. So couldn't it handle more flexible structure than OS's directory tree for itself ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Tue Jun 20 02:01:04 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA24419 for ; Tue, 20 Jun 2000 02:00:59 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA26090 for ; Tue, 20 Jun 2000 01:51:00 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id OAA10171; Tue, 20 Jun 2000 14:50:03 +0900 From: "Hiroshi Inoue" To: "Bruce Momjian" Cc: "Tom Lane" , "Jan Wieck" , "Ross J. Reedstrom" , "Don Baccus" , "PostgreSQL-development" Subject: RE: [HACKERS] Big 7.1 open items Date: Tue, 20 Jun 2000 14:52:17 +0900 Message-ID: <000001bfda7b$b0dbf160$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <200006191735.NAA03241@candle.pha.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Importance: Normal Status: ROr > -----Original Message----- > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > > -----Original Message----- > > > From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] > > > > > > The fact is that symlink information is already stored in the file > > > system. If we store symlink information in the database too, there > > > exists the ability for the two to get out of sync. My point is that I > > > think we can _not_ store symlink information in the database, > and query > > > the file system using lstat when required. > > > > > Hmm,this seems pretty confusing to me. > > I don't understand the necessity of symlink. > > Directory tree,symlink,hard link ... are OS's standard. > > But I don't think they are fit for dbms management. > > > > PostgreSQL is a database system of cource. So > > couldn't it handle more flexible structure than OS's > > directory tree for itself ? > > Yes, but is anyone suggesting a solution that does not work with > symlinks? If not, why not do it that way? > Maybe other solutions have been proposed already because there have been so many opinions and proposals. I've felt TABLE(DATA)SPACE discussion has always been divergent. IMHO,one of the main cause is that various factors have been discussed at once. Shouldn't we make step by step consensus in TABLE(DATA)SPACE discussion ? IMHO,the first step is to decide the syntax of CREATE TABLE command not to define TABLE(DATA)SPACE. Comments ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Tue Jun 20 10:51:32 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA15181 for ; Tue, 20 Jun 2000 10:51:31 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id KAA26466 for ; Tue, 20 Jun 2000 10:37:20 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id KAA29689; Tue, 20 Jun 2000 10:36:04 -0400 (EDT) To: Bruce Momjian cc: Hiroshi Inoue , Jan Wieck , "Ross J. Reedstrom" , Don Baccus , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006201340.JAA10387@candle.pha.pa.us> References: <200006201340.JAA10387@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Tue, 20 Jun 2000 09:40:03 -0400" Date: Tue, 20 Jun 2000 10:36:04 -0400 Message-ID: <29686.961511764@sss.pgh.pa.us> From: Tom Lane Status: RO Bruce Momjian writes: > Agreed. Seems we have several issues: > filename contents > tablespace implementation > tablespace directory layout > tablespace commands and syntax I think we've agreed that the filename must depend on tablespace, file version, and file segment number in some fashion --- plus the table name/OID of course. Although there's no real consensus about exactly how to construct the name, agreeing on the components is still a positive step. A couple of other areas of contention were: revising smgr interface to be cleaner exactly what to store in pg_class I don't think there's any quibble about the idea of cleaning up smgr, but we don't have a complete proposal on the table yet either. As for the pg_class issue, I still favor storing (a) OID of tablespace --- not for file access, but so that associated tablespace-table entry can be looked up by tablespace management operations (b) pathname of file as a column of type "name", including a %d to be replaced by segment # I think Peter was holding out for storing purely numeric tablespace OID and table version in pg_class and having a hardwired mapping to pathname somewhere in smgr. However, I think that doing it that way gains only micro-efficiency compared to passing a "name" around, while using the name approach buys us flexibility that's needed for at least some of the variants under discussion. Given that the exact filename contents are still so contentious, I think it'd be a bad idea to pick an implementation that doesn't allow some leeway as to what the filename will be. A name also has the advantage that it is a single item that can be used to identify the table to smgr, which will help in cleaning up the smgr interface. As for tablespace layout/implementation, the only real proposal I've heard is that there be a subdirectory of the database directory for each tablespace, and that that have a subdirectory for each segment (extent) of its tables --- where any of these subdirectories could be symlinks off to a different filesystem. Some unhappiness was raised about depending on symlinks for this function, but I didn't hear one single concrete reason not to do it, nor an alternative design. Unless someone comes up with a counterproposal, I think that that's what the actual access mechanism will look like. We still need to talk about what we want to store in the SQL-level representation of a tablespace, and what sort of tablespace management tools/commands are needed. (Although "try to make it look like Oracle" seems to be pretty much the consensus for the command level, not all of us know exactly what that means...) Comments? Anything else that we do have consensus on? regards, tom lane From pgsql-hackers-owner+M3615@hub.org Tue Jun 20 12:55:05 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA25768 for ; Tue, 20 Jun 2000 12:55:04 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA09949 for ; Tue, 20 Jun 2000 12:41:15 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5KGcCM19112; Tue, 20 Jun 2000 12:38:12 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by hub.org (8.10.1/8.10.1) with ESMTP id e5KGbbM18701 for ; Tue, 20 Jun 2000 12:37:37 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:43625 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Tue, 20 Jun 2000 18:37:05 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 134R7f-0003wS-00; Tue, 20 Jun 2000 18:43:35 +0200 Date: Tue, 20 Jun 2000 18:43:35 +0200 (CEST) From: Peter Eisentraut To: Bruce Momjian cc: Jan Wieck , Tom Lane , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <200006180316.XAA15410@candle.pha.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Bruce Momjian writes: > If we have a new CREATE DATABASE LOCATION command, we can say: > > CREATE DATABASE LOCATION dbloc IN '/var/private/pgsql'; > CREATE DATABASE newdb IN dbloc; We kind of have this already, with CREATE DATABASE foo WITH LOCATION = 'bar'; but of course with environment variable kludgery. But it's a start. > mkdir /var/private/pgsql/dbloc > ln -s /var/private/pgsql/dbloc data/base/dbloc I think the problem with this was that you'd have to do an extra lookup into, say, pg_location to resolve this. Some people are talking about blind writes, this is not really blind. > CREATE LOCATION tabloc IN '/var/private/pgsql'; > CREATE TABLE newtab ... IN tabloc; Okay, so we'd have "table spaces" and "database spaces". Seems like one "space" ought to be enough. I was thinking that the database "space" would serve as a default "space" for tables created within it but you could still create tables in other "spaces" than were the database really is. In fact, the database wouldn't show up at all in the file names anymore, which may or may not be a good thing. I think Tom suggested something more or less like this: $PGDATA/base/tablespace/segment/table (leaving the details of "table" aside for now). pg_class would get a column storing the table space somehow, say an oid reference to pg_location. There would have to be a default tablespace that's created by initdb and it's indicated by oid 0. So if you create a simple little table "foo" it ends up in $PGDATA/base/0/0/foo That is pretty manageable. Now to create a table space you do CREATE LOCATION "name" AT '/some/where'; which would make an entry in pg_location and, similar to how you suggested, create a symlink from $PGDATA/base/newoid -> /some/where Then when you create a new table at that new location this gets simply noted in pg_class with an oid reference, the rest works completely transparently and no lookup outside of pg_class required. The system would create the segment 0 subdirectory automatically. When tables get segmented the system would simply create subdirectories 1, 2, 3, etc. as needed, just as it created the 0 as need, no extra code. pg_dump doesn't need to use lstat or whatever at all because the locations are catalogued. Administrators don't even need to know about the linking business, they just make sure the target directory exists. Two more items to ponder: * per-location transaction logs * pg_upgrade -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From Inoue@tpf.co.jp Tue Jun 20 17:10:56 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA10307 for ; Tue, 20 Jun 2000 17:10:55 -0400 (EDT) Received: from sd.tpf.co.jp (mail.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id QAA08017 for ; Tue, 20 Jun 2000 16:57:44 -0400 (EDT) Received: from mcadnote1 (ppm127.noc.fukui.nsk.ne.jp [210.161.188.46]) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id FAA00867; Wed, 21 Jun 2000 05:56:44 +0900 From: "Hiroshi Inoue" To: "Tom Lane" , "Bruce Momjian" Cc: "Jan Wieck" , "Ross J. Reedstrom" , "Don Baccus" , "PostgreSQL-development" Subject: RE: [HACKERS] Big 7.1 open items Date: Wed, 21 Jun 2000 05:59:41 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 In-Reply-To: <29686.961511764@sss.pgh.pa.us> Importance: Normal Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > Bruce Momjian writes: > > Agreed. Seems we have several issues: > > > filename contents > > tablespace implementation > > tablespace directory layout > > tablespace commands and syntax > [snip] > > Comments? Anything else that we do have consensus on? > Before the details of tablespace implementation, 1) How to change(extend) the syntax of CREATE TABLE We only add table(data)space name with some keyword ? i.e Do we consider tablespace as an abstraction ? To confirm our mutual understanding. 2) Is tablespace defined per PostgreSQL's database ? 3) Is default tablespace defined per database/user or for all ? AFAIK in Oracle,2) global, 3) per user. Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Tue Jun 20 20:00:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA12668; Tue, 20 Jun 2000 20:00:58 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA21016; Tue, 20 Jun 2000 19:54:18 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id IAA00974; Wed, 21 Jun 2000 08:52:38 +0900 From: "Hiroshi Inoue" To: "Peter Eisentraut" Cc: "Jan Wieck" , "Tom Lane" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Bruce Momjian" Subject: RE: [HACKERS] Big 7.1 open items Date: Wed, 21 Jun 2000 08:54:51 +0900 Message-ID: <000e01bfdb12$ecc08f00$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 In-Reply-To: Importance: Normal Status: ROr > -----Original Message----- > From: Peter Eisentraut > > Bruce Momjian writes: > > > If we have a new CREATE DATABASE LOCATION command, we can say: > > > > CREATE DATABASE LOCATION dbloc IN '/var/private/pgsql'; > > CREATE DATABASE newdb IN dbloc; > > We kind of have this already, with CREATE DATABASE foo WITH LOCATION = > 'bar'; but of course with environment variable kludgery. But it's a start. > > > mkdir /var/private/pgsql/dbloc > > ln -s /var/private/pgsql/dbloc data/base/dbloc > > I think the problem with this was that you'd have to do an extra lookup > into, say, pg_location to resolve this. Some people are talking about > blind writes, this is not really blind. > > > CREATE LOCATION tabloc IN '/var/private/pgsql'; > > CREATE TABLE newtab ... IN tabloc; > > Okay, so we'd have "table spaces" and "database spaces". Seems like one > "space" ought to be enough. Does your "database space" correspond to current PostgreSQL's database ? And is it different from SCHEMA ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Wed Jun 21 00:23:48 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA18016; Wed, 21 Jun 2000 00:23:47 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id AAA05207; Wed, 21 Jun 2000 00:07:58 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id AAA03002; Wed, 21 Jun 2000 00:06:42 -0400 (EDT) To: Bruce Momjian cc: Hiroshi Inoue , Peter Eisentraut , Jan Wieck , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006210345.XAA15107@candle.pha.pa.us> References: <200006210345.XAA15107@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Tue, 20 Jun 2000 23:45:13 -0400" Date: Wed, 21 Jun 2000 00:06:42 -0400 Message-ID: <2999.961560402@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > I recommend making a dbname in each directory, then putting the > location inside there. This still seems backwards to me. Why is it better than tablespace directory inside database directory? One significant problem with it is that there's no longer (AFAICS) a "default" per-database directory that corresponds to the current working directory of backends running in that database. Thus, for example, it's not immediately clear where temporary files and backend core-dump files will end up. Also, you've just added an essential extra level (if not two) to the pathnames that backends will use to address files. There is a great deal to be said for ..../database/tablespace/filename where .../database/ is the working directory of a backend running in that database, so that the relative pathname used by that backend to get to a table is just tablespace/filename. I fail to see any advantage in reversing the pathname order. If you see one, enlighten me. regards, tom lane From pgsql-hackers-owner+M3635@hub.org Wed Jun 21 01:00:59 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA19614 for ; Wed, 21 Jun 2000 01:00:54 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5L4wA125142; Wed, 21 Jun 2000 00:58:10 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5L4vp125043 for ; Wed, 21 Jun 2000 00:57:51 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id NAA01462; Wed, 21 Jun 2000 13:52:47 +0900 From: "Hiroshi Inoue" To: "Tom Lane" , "Bruce Momjian" Cc: "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Wed, 21 Jun 2000 13:55:01 +0900 Message-ID: <000001bfdb3c$db728760$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-reply-to: <2999.961560402@sss.pgh.pa.us> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > Bruce Momjian writes: > > I recommend making a dbname in each directory, then putting the > > location inside there. > > This still seems backwards to me. Why is it better than tablespace > directory inside database directory? > > One significant problem with it is that there's no longer (AFAICS) > a "default" per-database directory that corresponds to the current > working directory of backends running in that database. Thus, > for example, it's not immediately clear where temporary files and > backend core-dump files will end up. Also, you've just added an > essential extra level (if not two) to the pathnames that backends will > use to address files. > > There is a great deal to be said for > ..../database/tablespace/filename OK,I seem to have gotten the answer for the question Is tablespace defined per PostgreSQL's database ? You and Bruce 1) tablespace is per database Peter seems to have the following idea(?? not sure) 2) database = tablespace My opinion 3) database and tablespace are relatively irrelevant. I assume PostgreSQL's database would correspond to the concept of SCHEMA. It seems we are different from the first. Shoudln't we reach an agreement on it in the first place ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3636@hub.org Wed Jun 21 01:31:12 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA20523 for ; Wed, 21 Jun 2000 01:31:12 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA08982 for ; Wed, 21 Jun 2000 01:15:17 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5L5Bp151546; Wed, 21 Jun 2000 01:11:51 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5L5BP151324 for ; Wed, 21 Jun 2000 01:11:25 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id BAA03463; Wed, 21 Jun 2000 01:09:52 -0400 (EDT) To: Chris Bitmead cc: Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <3950484D.417C87E9@nimrod.itg.telecom.com.au> References: <200006210346.XAA15138@candle.pha.pa.us> <3950484D.417C87E9@nimrod.itg.telecom.com.au> Comments: In-reply-to Chris Bitmead message dated "Wed, 21 Jun 2000 14:45:01 +1000" Date: Wed, 21 Jun 2000 01:09:52 -0400 Message-ID: <3459.961564192@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Chris Bitmead writes: > What I meant is, would you still be able to create tablespaces on > systems without symlinks? That would seem to be a desirable feature. All else being equal, it'd be nice. Since all else is not equal, exactly how much sweat are we willing to expend on supporting that feature on such systems --- to the exclusion of other features we might expend the same sweat on, with more widely useful results? Bear in mind that everything will still *work* just fine on such a platform, you just don't have a way to spread the database across multiple filesystems. That's only an issue if the platform has a fairly Unixy notion of filesystems ... but no symlinks. A few messages back someone was opining that we were wasting our time thinking about tablespaces at all, because any modern platform can create disk-spanning filesystems for itself, so applications don't have to worry. I don't buy that argument in general, but I'm quite willing to quote it for the *very* few systems that are Unixy enough to run Postgres in the first place, but not quite Unixy enough to have symlinks. You gotta draw the line somewhere at what you will support, and this particular line seems to me to be entirely reasonable and justifiable. YMMV... regards, tom lane From dhogaza@pacifier.com Wed Jun 21 01:31:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA20492 for ; Wed, 21 Jun 2000 01:30:58 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA09401 for ; Wed, 21 Jun 2000 01:22:50 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id WAA22395; Tue, 20 Jun 2000 22:21:47 -0700 (PDT) Message-Id: <3.0.1.32.20000620221248.0150f610@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Tue, 20 Jun 2000 22:12:48 -0700 To: "Philip J. Warner" , "Hiroshi Inoue" , "Tom Lane" , "Bruce Momjian" From: Don Baccus Subject: RE: [HACKERS] Big 7.1 open items Cc: "Jan Wieck" , "Ross J. Reedstrom" , "PostgreSQL-development" In-Reply-To: <3.0.5.32.20000621112210.01d97680@mail.rhyme.com.au> References: <29686.961511764@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 11:22 AM 6/21/00 +1000, Philip J. Warner wrote: >It may be worth considering leaving the CREATE TABLE statement alone. >Dec/RDB uses a new statement entirely to define where a table goes... It's worth considering, but on the other hand Oracle users greatly outnumber Compaq/RDB users these days... If there's no SQL92 guidance for implementing a feature, I'm pretty much in favor of tracking Oracle, whose SQL dialect is rapidly becoming a de-facto standard. I'm not saying I like the fact, Oracle's a pain in the ass. But when adopting existing syntax, might as well adopt that of the crushing borg. - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From lockhart@alumni.caltech.edu Wed Jun 21 01:31:07 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA20508; Wed, 21 Jun 2000 01:31:06 -0400 (EDT) Received: from huey.jpl.nasa.gov (huey.jpl.nasa.gov [128.149.68.100]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA09355; Wed, 21 Jun 2000 01:22:03 -0400 (EDT) Received: from golem.jpl.nasa.gov (hectic-1 [128.149.68.203]) by huey.jpl.nasa.gov (8.8.8+Sun/8.8.8) with ESMTP id WAA00821; Tue, 20 Jun 2000 22:18:38 -0700 (PDT) Received: from alumni.caltech.edu (localhost.localdomain [127.0.0.1]) by golem.jpl.nasa.gov (Postfix) with ESMTP id AF4376F51; Wed, 21 Jun 2000 05:19:29 +0000 (UTC) Sender: lockhart@mythos.jpl.nasa.gov Message-ID: <39505061.F42334AB@alumni.caltech.edu> Date: Wed, 21 Jun 2000 05:19:29 +0000 From: Thomas Lockhart Organization: Yes X-Mailer: Mozilla 4.7 [en] (X11; I; Linux 2.2.14-15mdksmp i686) X-Accept-Language: en MIME-Version: 1.0 To: Bruce Momjian Cc: Peter Eisentraut , Jan Wieck , Tom Lane , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <200006201753.NAA27293@candle.pha.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: ROr > Yes, I didn't like the environment variable stuff. In fact, I would > like to not mention the symlink location anywhere in the database, so > it can be changed without changing it in the database. Well, as y'all have noticed, I think there are strong reasons to use environment variables to manage locations, and that symlinks are a potential portability and robustness problem. An additional point which has relevance to this whole discussion: In the future we may allow system resource such as tables to carry names which use multi-byte encodings. afaik these encodings are not allowed to be used for physical file names, and even if they were the utility of using standard operating system utilities like ls goes way down. istm that from a portability and evolutionary standpoint OID-only file names (or at least file names *not* based on relation/class names) is a requirement. Comments? - Thomas From tgl@sss.pgh.pa.us Wed Jun 21 01:31:05 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA20503 for ; Wed, 21 Jun 2000 01:31:05 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA09513 for ; Wed, 21 Jun 2000 01:25:18 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id BAA03557; Wed, 21 Jun 2000 01:23:58 -0400 (EDT) To: "Hiroshi Inoue" cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <000001bfdb3c$db728760$2801007e@tpf.co.jp> References: <000001bfdb3c$db728760$2801007e@tpf.co.jp> Comments: In-reply-to "Hiroshi Inoue" message dated "Wed, 21 Jun 2000 13:55:01 +0900" Date: Wed, 21 Jun 2000 01:23:57 -0400 Message-ID: <3554.961565037@sss.pgh.pa.us> From: Tom Lane Status: ROr "Hiroshi Inoue" writes: >> There is a great deal to be said for >> ..../database/tablespace/filename > OK,I seem to have gotten the answer for the question > Is tablespace defined per PostgreSQL's database ? Not necessarily --- the tablespace subdirectories could be symlinks pointing to the same place (assuming you use OIDs or something to keep the table filenames unique even across databases). This is just an implementation mechanism; it doesn't foreclose the policy decision whether tablespaces are database-local or installation-wide. (OTOH, pathnames like tablespace/database would pretty much force tablespaces to be installation-wide whether you wanted it that way or not.) > My opinion > 3) database and tablespace are relatively irrelevant. > I assume PostgreSQL's database would correspond > to the concept of SCHEMA. My inclindation is that tablespaces should be installation-wide, but I'm not completely sold on it. In any case I could see wanting a permissions mechanism that would only allow some databases to have tables in a particular tablespace. We do need to think more about how traditional Postgres databases fit together with SCHEMA. Maybe we wouldn't even need multiple databases per installation if we had SCHEMA done right. regards, tom lane From pgsql-hackers-owner+M3641@hub.org Wed Jun 21 02:31:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA25698 for ; Wed, 21 Jun 2000 02:31:00 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id CAA11423 for ; Wed, 21 Jun 2000 02:09:13 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5L5we151226; Wed, 21 Jun 2000 01:58:40 -0400 (EDT) Received: from wallace.ece.rice.edu (wallace.ece.rice.edu [128.42.12.154]) by hub.org (8.10.1/8.10.1) with ESMTP id e5L5wE151030 for ; Wed, 21 Jun 2000 01:58:14 -0400 (EDT) Received: by rice.edu via sendmail from stdin id (Debian Smail3.2.0.102) for pgsql-hackers@postgresql.org; Wed, 21 Jun 2000 00:45:02 -0500 (CDT) Date: Wed, 21 Jun 2000 00:45:02 -0500 From: "Ross J. Reedstrom" To: Tom Lane Cc: Hiroshi Inoue , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items Message-ID: <20000621004502.A24387@rice.edu> Mail-Followup-To: Tom Lane , Hiroshi Inoue , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development References: <000001bfdb3c$db728760$2801007e@tpf.co.jp> <3554.961565037@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii User-Agent: Mutt/1.0i In-Reply-To: <3554.961565037@sss.pgh.pa.us>; from tgl@sss.pgh.pa.us on Wed, Jun 21, 2000 at 01:23:57AM -0400 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr On Wed, Jun 21, 2000 at 01:23:57AM -0400, Tom Lane wrote: > "Hiroshi Inoue" writes: > > > My opinion > > 3) database and tablespace are relatively irrelevant. > > I assume PostgreSQL's database would correspond > > to the concept of SCHEMA. > > My inclindation is that tablespaces should be installation-wide, but > I'm not completely sold on it. In any case I could see wanting a > permissions mechanism that would only allow some databases to have > tables in a particular tablespace. > > We do need to think more about how traditional Postgres databases > fit together with SCHEMA. Maybe we wouldn't even need multiple > databases per installation if we had SCHEMA done right. > The important point I think is that tablespaces are about physical storage/namespace, and SCHEMA are about logical namespace: it would make sense for tables from multiple schema to live in the same tablespace, as well as tables from one schema to be stored in multiple tablespaces. Ross -- Ross J. Reedstrom, Ph.D., NSBRI Research Scientist/Programmer Computer and Information Technology Institute Rice University, 6100 S. Main St., Houston, TX 77005 From pgsql-hackers-owner+M3644@hub.org Wed Jun 21 02:31:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA25704 for ; Wed, 21 Jun 2000 02:31:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id CAA11923 for ; Wed, 21 Jun 2000 02:22:41 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5L6JO196109; Wed, 21 Jun 2000 02:19:24 -0400 (EDT) Received: from mailo.vtcif.telstra.com.au (mailo.vtcif.telstra.com.au [202.12.144.17]) by hub.org (8.10.1/8.10.1) with ESMTP id e5L6JB196028 for ; Wed, 21 Jun 2000 02:19:11 -0400 (EDT) Received: (from uucp@localhost) by mailo.vtcif.telstra.com.au (8.8.2/8.6.9) id QAA21128 for ; Wed, 21 Jun 2000 16:19:04 +1000 (EST) Received: from maili.vtcif.telstra.com.au(202.12.142.17) via SMTP by mailo.vtcif.telstra.com.au, id smtpd08EKgu; Wed Jun 21 16:17:56 2000 Received: (from uucp@localhost) by maili.vtcif.telstra.com.au (8.8.2/8.6.9) id QAA02825 for ; Wed, 21 Jun 2000 16:17:55 +1000 (EST) Received: from localhost(127.0.0.1), claiming to be "mail.cdn.telstra.com.au" via SMTP by localhost, id smtpdnjRBD_; Wed Jun 21 16:17:14 2000 Received: from lunitari.nimrod.itg.telecom.com.au (lunitari.nimrod.itg.telecom.com.au [192.53.254.48]) by mail.cdn.telstra.com.au (8.8.2/8.6.9) with ESMTP id QAA07553 for ; Wed, 21 Jun 2000 16:17:14 +1000 (EST) Received: from nimrod.itg.telecom.com.au (majere [192.53.254.45]) by lunitari.nimrod.itg.telecom.com.au (8.9.1/8.9.3) with ESMTP id QAA05880 for ; Wed, 21 Jun 2000 16:15:56 +1000 (EST) Message-ID: <39505D1B.DA335CD2@nimrod.itg.telecom.com.au> Date: Wed, 21 Jun 2000 16:13:47 +1000 From: Chris Bitmead Organization: IBM Global Services X-Mailer: Mozilla 4.6 [en] (X11; I; SunOS 5.6 sun4u) X-Accept-Language: en MIME-Version: 1.0 To: PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items References: <000001bfdb3c$db728760$2801007e@tpf.co.jp> <3554.961565037@sss.pgh.pa.us> <20000621004502.A24387@rice.edu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Ross J. Reedstrom" wrote: > The important point I think is that tablespaces are about physical > storage/namespace, and SCHEMA are about logical namespace: it would make > sense for tables from multiple schema to live in the same tablespace, > as well as tables from one schema to be stored in multiple tablespaces. If we accept that argument (which sounds good) then wouldn't we have... data/base/db1/table1 -> ../../../tablespace/ts1/db1.table1 data/base/db1/table2 -> ../../../tablespace/ts1/db1.table2 data/tablespace/ts1/db1.table1 data/tablespace/ts1/db1.table2 In other words there is a directory for databases, and a directory for tablespaces. Database tables are symlinked to the appropriate tablespace. So there is multiple databases per tablespace and multiple tablespaces per database. From pgsql-hackers-owner+M3648@hub.org Wed Jun 21 09:01:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id JAA06055 for ; Wed, 21 Jun 2000 09:01:00 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id IAA29647 for ; Wed, 21 Jun 2000 08:52:25 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5LCo0112103; Wed, 21 Jun 2000 08:50:00 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by hub.org (8.10.1/8.10.1) with ESMTP id e5LCnS112011 for ; Wed, 21 Jun 2000 08:49:28 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id OAA27330; Wed, 21 Jun 2000 14:48:44 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Wed, 21 Jun 2000 14:48:44 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA5983@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Hiroshi Inoue'" Cc: "'pgsql-hackers@postgresql.org'" Subject: AW: [HACKERS] Big 7.1 open items Date: Wed, 21 Jun 2000 14:48:43 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > > > CREATE LOCATION tabloc IN '/var/private/pgsql'; > > > CREATE TABLE newtab ... IN tabloc; > > > > Okay, so we'd have "table spaces" and "database spaces". > Seems like one > > "space" ought to be enough. Yes, one space should be enough. > > Does your "database space" correspond to current PostgreSQL's > database ? I think we should think of the "database space" as the default "table space" for this database. > And is it different from SCHEMA ? Please don't mix schema and database, they are two different issues. Even Oracle has a database, only in Oracle you are limited to one database per instance. We do not want to add this limitation to PostgreSQL. Andreas From e99re41@DoCS.UU.SE Wed Jun 21 10:01:10 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA06585; Wed, 21 Jun 2000 10:01:09 -0400 (EDT) Received: from meryl.it.uu.se (root@meryl.it.uu.se [130.238.12.42]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id JAA03592; Wed, 21 Jun 2000 09:38:34 -0400 (EDT) Received: from Ulv.DoCS.UU.SE (e99re41@Ulv.DoCS.UU.SE [130.238.9.167]) by meryl.it.uu.se (8.8.5/8.8.5) with ESMTP id PAA20520; Wed, 21 Jun 2000 15:34:34 +0200 (MET DST) Received: from localhost (e99re41@localhost) by Ulv.DoCS.UU.SE (8.6.12/8.6.12) with ESMTP id PAA10847; Wed, 21 Jun 2000 15:34:27 +0200 X-Authentication-Warning: Ulv.DoCS.UU.SE: e99re41 owned process doing -bs Date: Wed, 21 Jun 2000 15:34:27 +0200 (MET DST) From: Peter Eisentraut Reply-To: Peter Eisentraut To: Hiroshi Inoue cc: Tom Lane , Bruce Momjian , Jan Wieck , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items In-Reply-To: <000001bfdb3c$db728760$2801007e@tpf.co.jp> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by candle.pha.pa.us id KAA06585 Status: RO On Wed, 21 Jun 2000, Hiroshi Inoue wrote: > Peter seems to have the following idea(?? not sure) > 2) database = tablespace No, I thought that a database would have a table space assigned that would serve as the default for newly created tables, but could be overridden. So you could group databases onto disks as you want, but a couple of particularly big/important/unimportant/etc tables from each database could be put on a different disk. At least this seems to be the most flexible and conceptually simple solution. Ideally, directories per database would go away, but then we'd have the system tables colliding, since those have the same oid in each database. But that's not really important. So essentially you'd have $PGDATA/base/tablespacesomething/database/tables In the default tablespace, "tablespacesomething" is an ordinary directory, for other tablespaces it symlinks somewhere else. For those browsing $PGDATA/base, it all looks the same (unless you have colour ls). For those browsing the actual storage location it looks like /var/foo/elsewhere/database/tables. I'm sure you can squeeze the extension segments in there, maybe between tablespace and database. What I think Bruce is saying is that there should be both database spaces and table spaces, I think that's too much. > My opinion > 3) database and tablespace are relatively irrelevant. > I assume PostgreSQL's database would correspond > to the concept of SCHEMA. A database corresponds to a catalog and a schema corresponds to nothing yet. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From e99re41@DoCS.UU.SE Wed Jun 21 10:01:09 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA06582; Wed, 21 Jun 2000 10:01:08 -0400 (EDT) Received: from meryl.it.uu.se (root@meryl.it.uu.se [130.238.12.42]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id JAA04510; Wed, 21 Jun 2000 09:43:48 -0400 (EDT) Received: from Ulv.DoCS.UU.SE (e99re41@Ulv.DoCS.UU.SE [130.238.9.167]) by meryl.it.uu.se (8.8.5/8.8.5) with ESMTP id PAA20730; Wed, 21 Jun 2000 15:39:23 +0200 (MET DST) Received: from localhost (e99re41@localhost) by Ulv.DoCS.UU.SE (8.6.12/8.6.12) with ESMTP id PAA10853; Wed, 21 Jun 2000 15:39:16 +0200 X-Authentication-Warning: Ulv.DoCS.UU.SE: e99re41 owned process doing -bs Date: Wed, 21 Jun 2000 15:39:16 +0200 (MET DST) From: Peter Eisentraut Reply-To: Peter Eisentraut To: Bruce Momjian cc: Jan Wieck , Tom Lane , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <200006201753.NAA27293@candle.pha.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by candle.pha.pa.us id KAA06582 Status: ROr On Tue, 20 Jun 2000, Bruce Momjian wrote: > What I was suggesting is not to catalog the symlink locations, but to > use lstat when dumping, so that admins can move files around using > symlinks and not have to udpate the database. That surely wouldn't make those happy that are calling for smgr abstraction. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From tgl@sss.pgh.pa.us Wed Jun 21 11:31:09 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA08120; Wed, 21 Jun 2000 11:31:08 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id LAA13232; Wed, 21 Jun 2000 11:08:38 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id LAA04286; Wed, 21 Jun 2000 11:07:20 -0400 (EDT) To: Bruce Momjian cc: Hiroshi Inoue , Peter Eisentraut , Jan Wieck , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006210433.AAA18343@candle.pha.pa.us> References: <200006210433.AAA18343@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 21 Jun 2000 00:33:01 -0400" Date: Wed, 21 Jun 2000 11:07:20 -0400 Message-ID: <4283.961600040@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > Yes, agreed. I was thinking this: > CREATE TABLESPACE loc USING '/var/pgsql' > does: > ln -s /var/pgsql/dbname/loc data/base/dbname/loc > In this way, the database has a view of its main directory, plus a /loc > subdirectory for the tablespace. In the other location, we have > /var/pgsql/dbname/loc because this allows different databases to use: > CREATE TABLESPACE loc USING '/var/pgsql' > and they do not collide with each other in /var/pgsql. But they don't collide anyway, because the dbname is already unique. Isn't the extra subdirectory a waste? Because table files will have installation-wide unique names, there's no really good reason to have either level of subdirectory; you could just make CREATE TABLESPACE loc USING '/var/pgsql' do ln -s /var/pgsql data/base/dbname/loc and it'd still work even if multiple DBs were using the same tablespace. However, forcing creation of a subdirectory does give you the chance to make sure the subdir is owned by postgres and has the right permissions, so there's something to be said for that. It might be reasonable to do mkdir /var/pgsql/dbname chmod 700 /var/pgsql/dbname ln -s /var/pgsql/dbname data/base/dbname/loc regards, tom lane From lockhart@alumni.caltech.edu Wed Jun 21 11:31:10 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA08135; Wed, 21 Jun 2000 11:31:09 -0400 (EDT) Received: from huey.jpl.nasa.gov (huey.jpl.nasa.gov [128.149.68.100]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id LAA15864; Wed, 21 Jun 2000 11:30:06 -0400 (EDT) Received: from golem.jpl.nasa.gov (hectic-1 [128.149.68.203]) by huey.jpl.nasa.gov (8.8.8+Sun/8.8.8) with ESMTP id IAA02881; Wed, 21 Jun 2000 08:26:40 -0700 (PDT) Received: from alumni.caltech.edu (localhost.localdomain [127.0.0.1]) by golem.jpl.nasa.gov (Postfix) with ESMTP id AB8AE6F51; Wed, 21 Jun 2000 15:27:36 +0000 (UTC) Sender: lockhart@mythos.jpl.nasa.gov Message-ID: <3950DEE8.2DB4B401@alumni.caltech.edu> Date: Wed, 21 Jun 2000 15:27:36 +0000 From: Thomas Lockhart Organization: Yes X-Mailer: Mozilla 4.7 [en] (X11; I; Linux 2.2.14-15mdksmp i686) X-Accept-Language: en MIME-Version: 1.0 To: Bruce Momjian Cc: Peter Eisentraut , Jan Wieck , Tom Lane , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <200006211511.LAA07416@candle.pha.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: RO > Sorry, disagree. Environment variables are a pain to administer, and > quite counter-intuitive. Well, I guess we disagree. But until we have a complete proposed solution, we should leave environment variables on the table, since they *do* allow some decoupling of logical and physical storage, and *do* give the administrator some control over resources *that the admin would not otherwise have*. > > istm that from a portability and evolutionary standpoint OID-only > > file names (or at least file names *not* based on relation/class > > names) is a requirement. > Maybe a requirement at some point for some installations, but I hope > not a general requirement. If a table name can have characters which are not legal for file names, then how would you propose to support it? If we are doing a restructuring of the storage scheme, this should be taken into account. lockhart=# create table "one/two" (i int); ERROR: cannot create one/two Why not? It demonstrates an unfortunate linkage between file systems and database resources. - Thomas From tgl@sss.pgh.pa.us Wed Jun 21 11:31:18 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA08164; Wed, 21 Jun 2000 11:31:12 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id LAA15786; Wed, 21 Jun 2000 11:29:30 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id LAA04451; Wed, 21 Jun 2000 11:28:09 -0400 (EDT) To: Thomas Lockhart cc: Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <39505061.F42334AB@alumni.caltech.edu> References: <200006201753.NAA27293@candle.pha.pa.us> <39505061.F42334AB@alumni.caltech.edu> Comments: In-reply-to Thomas Lockhart message dated "Wed, 21 Jun 2000 05:19:29 -0000" Date: Wed, 21 Jun 2000 11:28:09 -0400 Message-ID: <4448.961601289@sss.pgh.pa.us> From: Tom Lane Status: RO Thomas Lockhart writes: > Well, as y'all have noticed, I think there are strong reasons to use > environment variables to manage locations, and that symlinks are a > potential portability and robustness problem. Reasons? Evidence? > An additional point which has relevance to this whole discussion: > In the future we may allow system resource such as tables to carry names > which use multi-byte encodings. afaik these encodings are not allowed to > be used for physical file names, and even if they were the utility of > using standard operating system utilities like ls goes way down. Good point, although in one sense a string is a string --- as long as we don't allow embedded nulls in server-side encodings, we could use anything that Postgres thought was a name in a filename, and the OS should take it. But if your local ls doesn't show it the way you see in Postgres, the usefulness of having the tablename in the filename goes way down. > istm that from a portability and evolutionary standpoint OID-only file > names (or at least file names *not* based on relation/class names) is a > requirement. No argument from me ;-). I've been looking for compromise positions but I still think that pure numeric filenames are the cleanest solution. There's something else that should be taken into account: for WAL, the log will need to record the table file that each insert/delete/update operation affects. To do that with the smgr-token-is-a-pathname approach I was suggesting yesterday, I think you have to record the database name and pathname in each WAL log entry. That's 64 bytes/log entry which is a *lot*. If we bit the bullet and restricted ourselves to numeric filenames then the log would need just four numeric values: database OID tablespace OID relation OID relation version number (this set of 4 values would also be an smgr file reference token). 16 bytes/log entry looks much better than 64. At the moment I can recall the following opinions: Pure OID filenames: Thomas, Tom, Marc, Peter E. OID+relname filenames: Bruce Vadim was in the pure-OID camp a few months ago, but I won't presume to list him there now since he hasn't been involved in this most recent round of discussions. I'm not sure where anyone else stands... but at least in terms of the core group it's pretty clear where the majority opinion is. regards, tom lane From lamar.owen@wgcr.org Wed Jun 21 11:51:39 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA09021; Wed, 21 Jun 2000 11:51:38 -0400 (EDT) Received: from www.wgcr.org (IDENT:root@www.wgcr.org [206.74.232.194]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id LAA18613; Wed, 21 Jun 2000 11:51:48 -0400 (EDT) Received: from wgcr.org ([206.74.232.197]) by www.wgcr.org (8.9.3/8.9.3/WGCR) with ESMTP id LAA19124; Wed, 21 Jun 2000 11:48:25 -0400 Message-ID: <3950E3C3.7322BD70@wgcr.org> Date: Wed, 21 Jun 2000 11:48:19 -0400 From: Lamar Owen X-Mailer: Mozilla 4.61 [en] (Win95; I) X-Accept-Language: en MIME-Version: 1.0 To: Tom Lane CC: Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <200006201753.NAA27293@candle.pha.pa.us> <39505061.F42334AB@alumni.caltech.edu> <4448.961601289@sss.pgh.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Status: ROr Tom Lane wrote: > Thomas Lockhart writes: > > Well, as y'all have noticed, I think there are strong reasons to use > > environment variables to manage locations, and that symlinks are a > > potential portability and robustness problem. > Reasons? Evidence? Does Win32 do symlinks these days? I know Win32 does envvars, and Win32 is currently a supported platform. I'm not thrilled with either solution -- envvars have their problems just as surely as symlinks do. > At the moment I can recall the following opinions: > Pure OID filenames: Thomas, Tom, Marc, Peter E. FWIW, count me here. I have tried administering my system using the filenames -- and have been bitten. Better admin tools in the PostgreSQL package beat using standard filesystem tools -- the PostgreSQL tools can be WAL-aware, transaction-aware, and can provide consistent results. Filesystem tools never will be able to provide consistent results for a database system that must remain up 24x7, as many if not most PostgreSQL installations must. > OID+relname filenames: Bruce Sorry Bruce -- I understand and am sympathetic to your position, and, at one time, I agreed with it. But not any more. -- Lamar Owen WGCR Internet Radio 1 Peter 4:11 From tgl@sss.pgh.pa.us Wed Jun 21 12:10:06 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA09885 for ; Wed, 21 Jun 2000 12:10:04 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA04789; Wed, 21 Jun 2000 12:10:15 -0400 (EDT) To: Bruce Momjian cc: Hiroshi Inoue , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006211545.LAA08773@candle.pha.pa.us> References: <200006211545.LAA08773@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 21 Jun 2000 11:45:12 -0400" Date: Wed, 21 Jun 2000 12:10:15 -0400 Message-ID: <4786.961603815@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > Yes, that is true. My idea is that they may want to create loc1 and > loc2 which initially point to the same location, but later may be moved. > For example, one tablespace for tables, another for indexes. They may > initially point to the same directory, but later be split. Well, that opens up a completely different issue, which is what about moving tables from one tablespace to another? I think the way you appear to be implying above (shut down the server so that you can rearrange subdirectories by hand) is the wrong way to go about it. For one thing, lots of people don't want to shut down their servers completely for that long, but it's difficult to avoid doing so if you want to move files by filesystem commands. For another thing, the above approach requires guessing in advance --- maybe long in advance --- how you are going to want to repartition your database when it gets too big for your existing storage. The right way to address this problem is to invent a "move table to new tablespace" command. This'd be pretty trivial to implement based on a file-versioning approach: the new version of the pg_class tuple has a new tablespace identifier in it. regards, tom lane From pgsql-hackers-owner+M3670@hub.org Wed Jun 21 12:30:42 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA10371 for ; Wed, 21 Jun 2000 12:30:41 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA22315 for ; Wed, 21 Jun 2000 12:23:18 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5LGJU175424; Wed, 21 Jun 2000 12:19:30 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5LGJJ175359 for ; Wed, 21 Jun 2000 12:19:19 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA04878; Wed, 21 Jun 2000 12:17:38 -0400 (EDT) To: Bruce Momjian cc: Lamar Owen , Thomas Lockhart , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006211603.MAA09414@candle.pha.pa.us> References: <200006211603.MAA09414@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 21 Jun 2000 12:03:12 -0400" Date: Wed, 21 Jun 2000 12:17:37 -0400 Message-ID: <4875.961604257@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Bruce Momjian writes: >> Sorry Bruce -- I understand and am sympathetic to your position, and, at >> one time, I agreed with it. But not any more. > I thought the most recent proposal was to just throw ~16 chars of the > file name on the end of the file name, and that should not be used for > anything except visibility. WAL would not need to store that. It could > just grab the file name that matches the oid/sequence number. But that's extra complexity in WAL, plus extra complexity in renaming tables (if you want the filename to track the logical table name, which I expect you would), plus extra complexity in smgr and bufmgr and other places. I think people are coming around to the notion that it's better to keep these low-level operations simple, even if we need to expend more work on high-level admin tools as a result. But we do need to remember to expend that effort on tools! Let's not drop the ball on that, folks. regards, tom lane From tgl@sss.pgh.pa.us Wed Jun 21 12:30:40 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA10364 for ; Wed, 21 Jun 2000 12:30:38 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA22593 for ; Wed, 21 Jun 2000 12:25:58 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA04944; Wed, 21 Jun 2000 12:24:44 -0400 (EDT) To: Bruce Momjian cc: Hiroshi Inoue , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006211614.MAA09938@candle.pha.pa.us> References: <200006211614.MAA09938@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 21 Jun 2000 12:14:59 -0400" Date: Wed, 21 Jun 2000 12:24:44 -0400 Message-ID: <4941.961604684@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: >> Well, that opens up a completely different issue, which is what about >> moving tables from one tablespace to another? > Are you suggesting that doing dbname/locname is somehow harder to do > that? If you are, I don't understand why. It doesn't make it harder, but it still seems pointless to have the extra directory level. Bear in mind that if we go with all-OID filenames then you're not going to be looking at "loc1" and "loc2" anyway, but at "5938171" and "8583727". It's not much of a convenience to the admin to see that, so we might as well save a level of directory lookup. > The general issue of moving tables between tablespaces can be done from > in the database. I don't think it is reasonable to shut down the db to > do that. However, I can see moving tablespaces to different symlinked > locations may require a shutdown. Only if you insist on doing it outside the database using filesystem tools. Another way is to create a new tablespace in the desired new location, then move the tables one-by-one to that new tablespace. I suppose either one might be preferable depending on your access patterns --- locking your most critical tables while they're being moved might be as bad as a total shutdown. regards, tom lane From tgl@sss.pgh.pa.us Wed Jun 21 13:01:06 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA11366 for ; Wed, 21 Jun 2000 13:01:05 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA24726 for ; Wed, 21 Jun 2000 12:47:50 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA05112; Wed, 21 Jun 2000 12:46:34 -0400 (EDT) To: Bruce Momjian cc: Hiroshi Inoue , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006211640.MAA10498@candle.pha.pa.us> References: <200006211640.MAA10498@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 21 Jun 2000 12:40:35 -0400" Date: Wed, 21 Jun 2000 12:46:34 -0400 Message-ID: <5109.961605994@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: >>>> Are you suggesting that doing dbname/locname is somehow harder to do >>>> that? If you are, I don't understand why. >> >> It doesn't make it harder, but it still seems pointless to have the >> extra directory level. Bear in mind that if we go with all-OID >> filenames then you're not going to be looking at "loc1" and "loc2" >> anyway, but at "5938171" and "8583727". It's not much of a convenience >> to the admin to see that, so we might as well save a level of directory >> lookup. > Just seems easier to have stuff segregates into separate per-db > directories for clarity. Also, as directories get bigger, finding a > specific file in there becomes harder. Putting 10 databases all in the > same directory seems bad in this regard. Huh? I wasn't arguing against making a db-specific directory below the tablespace point. I was arguing against making *another* directory below that one. > I don't think we want to be using > symlinks for tables if we can avoid it. Agreed, but where did that come from? None of these proposals mentioned symlinks for anything but directories, AFAIR. regards, tom lane From peter@localhost.its.uu.se Wed Jun 21 14:31:13 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA13233 for ; Wed, 21 Jun 2000 14:31:13 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id OAA04201 for ; Wed, 21 Jun 2000 14:11:42 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:34923 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Wed, 21 Jun 2000 20:09:46 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 134p2o-0000Uo-00; Wed, 21 Jun 2000 20:16:10 +0200 Date: Wed, 21 Jun 2000 20:16:10 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: Bruce Momjian , Hiroshi Inoue , Jan Wieck , "Ross J. Reedstrom" , Don Baccus , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <29686.961511764@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: Peter Eisentraut Status: ROr Tom Lane writes: > I think Peter was holding out for storing purely numeric tablespace OID > and table version in pg_class and having a hardwired mapping to pathname > somewhere in smgr. However, I think that doing it that way gains only > micro-efficiency compared to passing a "name" around, while using the > name approach buys us flexibility that's needed for at least some of > the variants under discussion. But that name can only be a dozen or so characters, contain no slash or other funny characters, etc. That's really poor. Then the alternative is to have an internal name and an external canonical name. Then you have two names to worry about. Also consider that when you store both the table space oid and the internal name in pg_class you create redundant data. What if you rename the table space? Do you leave the internal name out of sync? Then what good is the internal name? I'm just concerned that we are creating at the table space level problems similar to that we're trying to get rid of at the relation and database level. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From tgl@sss.pgh.pa.us Wed Jun 21 18:14:19 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id SAA24147 for ; Wed, 21 Jun 2000 18:14:18 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id RAA24649 for ; Wed, 21 Jun 2000 17:40:59 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id RAA06031; Wed, 21 Jun 2000 17:39:38 -0400 (EDT) To: Bruce Momjian cc: Peter Eisentraut , Hiroshi Inoue , Jan Wieck , "Ross J. Reedstrom" , Don Baccus , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006211842.OAA13514@candle.pha.pa.us> References: <200006211842.OAA13514@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 21 Jun 2000 14:42:21 -0400" Date: Wed, 21 Jun 2000 17:39:38 -0400 Message-ID: <6028.961623578@sss.pgh.pa.us> From: Tom Lane Status: RO Bruce Momjian writes: >> But that name can only be a dozen or so characters, contain no slash or >> other funny characters, etc. That's really poor. Then the alternative is >> to have an internal name and an external canonical name. Then you have two >> names to worry about. Also consider that when you store both the table >> space oid and the internal name in pg_class you create redundant data. >> What if you rename the table space? Do you leave the internal name out of >> sync? Then what good is the internal name? I'm just concerned that we are >> creating at the table space level problems similar to that we're trying to >> get rid of at the relation and database level. > Agreed. Having table spaces stored by directories named by oid just > seems very complicated for no reason. Huh? He just gave you two very good reasons: avoid Unix-derived limitations on the naming of tablespaces (and tables), and avoid problems with renaming tablespaces. I'm pretty much firmly back in the "OID and nothing but" camp. Or perhaps I should say "OID, file version, and nothing but", since we still need a version number to do CLUSTER etc. regards, tom lane From vmikheev@SECTORBASE.COM Wed Jun 21 22:18:38 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07570; Wed, 21 Jun 2000 22:18:36 -0400 (EDT) Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA29965; Wed, 21 Jun 2000 19:07:37 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Wed, 21 Jun 2000 15:58:30 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C2B@SECTORBASE1> From: "Mikheev, Vadim" To: "'Tom Lane'" , Thomas Lockhart Cc: Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Wed, 21 Jun 2000 16:00:17 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: RO > If we bit the bullet and restricted ourselves to numeric filenames then > the log would need just four numeric values: > database OID > tablespace OID Is someone going to implement it for 7.1? > relation OID > relation version number I believe that we can avoid versions using WAL... > (this set of 4 values would also be an smgr file reference token). > 16 bytes/log entry looks much better than 64. > > At the moment I can recall the following opinions: > > Pure OID filenames: Thomas, Tom, Marc, Peter E. + me. But what about LOCATIONs? I object using environment and think that locations must be stored in pg_control..? Vadim From Inoue@tpf.co.jp Wed Jun 21 22:18:39 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07573; Wed, 21 Jun 2000 22:18:38 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id TAA01857; Wed, 21 Jun 2000 19:37:04 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id IAA02627; Thu, 22 Jun 2000 08:35:27 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 08:37:42 +0900 Message-ID: <000201bfdbd9$b1985580$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <4448.961601289@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > No argument from me ;-). I've been looking for compromise positions > but I still think that pure numeric filenames are the cleanest solution. > > There's something else that should be taken into account: for WAL, the > log will need to record the table file that each insert/delete/update > operation affects. To do that with the smgr-token-is-a-pathname > approach I was suggesting yesterday, I think you have to record the > database name and pathname in each WAL log entry. That's 64 bytes/log > entry which is a *lot*. If we bit the bullet and restricted ourselves > to numeric filenames then the log would need just four numeric values: > database OID > tablespace OID I strongly object to keep tablespace OID for smgr file reference token though we have to keep it for another purpose of cource. I've mentioned many times tablespace(where to store) info should be distinguished from *where it is stored* info. Generally tablespace isn't sufficiently restrictive for this purpose. e.g. there was an idea about round-robin. e.g. Oracle's tablespace could have pluaral files... etc. IMHO,it is misleading to use tablespace OID as (a part of) reference token. > relation OID > relation version number > (this set of 4 values would also be an smgr file reference token). > 16 bytes/log entry looks much better than 64. > Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Wed Jun 21 22:18:15 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07540; Wed, 21 Jun 2000 22:18:11 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id UAA04100; Wed, 21 Jun 2000 20:15:09 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id JAA02691; Thu, 22 Jun 2000 09:14:15 +0900 From: "Hiroshi Inoue" To: "Mikheev, Vadim" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "'Tom Lane'" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 09:16:30 +0900 Message-ID: <000301bfdbdf$1d0dd920$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <8F4C99C66D04D4118F580090272A7A23018C2B@SECTORBASE1> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Mikheev, Vadim [mailto:vmikheev@SECTORBASE.COM] > > > If we bit the bullet and restricted ourselves to numeric filenames then > > the log would need just four numeric values: > > database OID > > tablespace OID > > Is someone going to implement it for 7.1? > > > relation OID > > relation version number > > I believe that we can avoid versions using WAL... > How to re-construct tables in place ? Is the following right ? 1) save the content of current table to somewhere 2) shrink the table and related indexes 3) reload the saved(+some filtering) content Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Wed Jun 21 22:18:16 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07553; Wed, 21 Jun 2000 22:18:15 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id UAA05872; Wed, 21 Jun 2000 20:44:21 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id JAA02750; Thu, 22 Jun 2000 09:43:31 +0900 From: "Hiroshi Inoue" To: "Mikheev, Vadim" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "'Tom Lane'" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 09:45:46 +0900 Message-ID: <000401bfdbe3$3420fee0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <8F4C99C66D04D4118F580090272A7A23018C2C@SECTORBASE1> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Mikheev, Vadim [mailto:vmikheev@SECTORBASE.COM] > > > > > relation version number > > > > > > I believe that we can avoid versions using WAL... > > > > > > > How to re-construct tables in place ? > > Is the following right ? > > 1) save the content of current table to somewhere > > 2) shrink the table and related indexes > > 3) reload the saved(+some filtering) content > > Or - create tmp file and load with new content; log "intent to > relink table > file"; > relink table file; log "file is relinked". > It seems to me that whole content of the table should be logged before relinking or shrinking. Is my understanding right ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3700@hub.org Wed Jun 21 22:17:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07504 for ; Wed, 21 Jun 2000 22:17:58 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id VAA07914 for ; Wed, 21 Jun 2000 21:23:22 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5M1It194420; Wed, 21 Jun 2000 21:18:55 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5M1Ig194334 for ; Wed, 21 Jun 2000 21:18:43 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id KAA02808; Thu, 22 Jun 2000 10:12:45 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 10:15:01 +0900 Message-ID: <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <4448.961601289@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > At the moment I can recall the following opinions: > > Pure OID filenames: Thomas, Tom, Marc, Peter E. > > OID+relname filenames: Bruce > Please add my opinion to the list. Unique-id filename: Hiroshi (Unqiue-id is irrelevant to OID/relname). Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3701@hub.org Wed Jun 21 22:18:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07513 for ; Wed, 21 Jun 2000 22:18:01 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id VAA08502 for ; Wed, 21 Jun 2000 21:33:13 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5M1QS107400; Wed, 21 Jun 2000 21:26:28 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5M1QA107223 for ; Wed, 21 Jun 2000 21:26:10 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id KAA02831; Thu, 22 Jun 2000 10:25:11 +0900 From: "Hiroshi Inoue" To: "Mikheev, Vadim" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "'Tom Lane'" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 10:27:26 +0900 Message-ID: <000601bfdbe9$0658a980$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <8F4C99C66D04D4118F580090272A7A23018C2D@SECTORBASE1> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Mikheev, Vadim [mailto:vmikheev@SECTORBASE.COM] > > > > Or - create tmp file and load with new content; > > > log "intent to relink table file"; > > > relink table file; log "file is relinked". > > > > It seems to me that whole content of the table should be > > logged before relinking or shrinking. > > Why not just fsync tmp files? > Probably I've misunderstood *relink*. If *relink* different from *rename* ? Regards. Hiroshi Inoue Inoue@tpf.co.jp From vmikheev@SECTORBASE.COM Wed Jun 21 22:17:52 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id WAA07492; Wed, 21 Jun 2000 22:17:51 -0400 (EDT) Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id VAA08730; Wed, 21 Jun 2000 21:37:44 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Wed, 21 Jun 2000 18:28:36 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C2F@SECTORBASE1> From: "Mikheev, Vadim" To: "'Hiroshi Inoue'" Cc: Bruce Momjian , Peter Eisentraut , Jan Wieck , Bruce Momjian , PostgreSQL-development , "Ross J. Reedstrom" , "'Tom Lane'" , Thomas Lockhart Subject: RE: [HACKERS] Big 7.1 open items Date: Wed, 21 Jun 2000 18:30:23 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: RO > > > > Or - create tmp file and load with new content; > > > > log "intent to relink table file"; > > > > relink table file; log "file is relinked". > > > > > > It seems to me that whole content of the table should be > > > logged before relinking or shrinking. > > > > Why not just fsync tmp files? > > > > Probably I've misunderstood *relink*. > If *relink* different from *rename* ? I ment something like this - link(table file, tmp2 file); fsync(tmp2 file); unlink(table file); link(tmp file, table file); fsync(table file); unlink(tmp file). We can do additional logging (with log flush) of these steps if required, postpone on-recovery redo of operations till last relink log record/ end of log/transaction abort etc etc etc. Vadim From Inoue@tpf.co.jp Wed Jun 21 23:22:36 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA10350 for ; Wed, 21 Jun 2000 23:22:35 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id XAA13743 for ; Wed, 21 Jun 2000 23:07:50 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id MAA03008; Thu, 22 Jun 2000 12:07:00 +0900 From: "Hiroshi Inoue" To: "Mikheev, Vadim" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "'Tom Lane'" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 12:09:15 +0900 Message-ID: <000801bfdbf7$3f674200$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <8F4C99C66D04D4118F580090272A7A23018C2F@SECTORBASE1> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Mikheev, Vadim [mailto:vmikheev@SECTORBASE.COM] > > > > > > Or - create tmp file and load with new content; > > > > > log "intent to relink table file"; > > > > > relink table file; log "file is relinked". > > > > > > > > It seems to me that whole content of the table should be > > > > logged before relinking or shrinking. > > > > > > Why not just fsync tmp files? > > > > > > > Probably I've misunderstood *relink*. > > If *relink* different from *rename* ? > > I ment something like this - link(table file, tmp2 file); > fsync(tmp2 file); > unlink(table file); link(tmp file, table file); fsync(table file); > unlink(tmp file). I see,old file would be rolled back from tmp2 file on abort. This would work on most platforms. But cygwin port has a flaw that files could not be unlinked if they are open. So *relink* may fail in some cases(including rollback cases). Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Wed Jun 21 23:22:38 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA10353 for ; Wed, 21 Jun 2000 23:22:36 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id XAA14206 for ; Wed, 21 Jun 2000 23:16:26 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id XAA07099; Wed, 21 Jun 2000 23:14:50 -0400 (EDT) To: "Mikheev, Vadim" cc: Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <8F4C99C66D04D4118F580090272A7A23018C2B@SECTORBASE1> References: <8F4C99C66D04D4118F580090272A7A23018C2B@SECTORBASE1> Comments: In-reply-to "Mikheev, Vadim" message dated "Wed, 21 Jun 2000 16:00:17 -0700" Date: Wed, 21 Jun 2000 23:14:50 -0400 Message-ID: <7096.961643690@sss.pgh.pa.us> From: Tom Lane Status: RO "Mikheev, Vadim" writes: >> relation OID >> relation version number > I believe that we can avoid versions using WAL... I don't think so. You're basically saying that 1. create file 'new' 2. delete file 'old' 3. rename 'new' to 'old' is safe as long as you have a redo log to ensure that the rename happens even if you crash between steps 2 and 3. But crash is not the only hazard. What if step 3 just plain fails? Redo won't help. I'm having a hard time inventing really plausible examples, but a slightly implausible example is that someone chmod's the containing directory -w between steps 2 and 3. (Maybe it's not so implausible if you assume a crash after step 2 ... someone might have left the directory nonwritable while restoring the system.) If we use file version numbers, then the *only* thing needed to make a valid transition between one set of files and another is a commit of the update of pg_class that shows the new version number in the rel's pg_class tuple. The worst that can happen to you in a crash or other failure is that you are unable to get rid of the set of files that you don't want anymore. That might waste disk space but it doesn't leave the database corrupted. > But what about LOCATIONs? I object using environment and think that > locations must be stored in pg_control..? I don't like environment variables for this either; it's just way too easy to start the postmaster with wrong environment. It still seems to me that relying on subdirectory symlinks is a good way to go. pg_control is not so good --- if it gets corrupted, how do you recover? symlinks can be recreated by hand if necessary, but... regards, tom lane From pgsql-hackers-owner+M3711@hub.org Thu Jun 22 01:01:06 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA22245 for ; Thu, 22 Jun 2000 01:01:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id AAA18310 for ; Thu, 22 Jun 2000 00:43:00 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5M3US167109; Wed, 21 Jun 2000 23:30:28 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5M3U0164115 for ; Wed, 21 Jun 2000 23:30:00 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id XAA07156; Wed, 21 Jun 2000 23:27:10 -0400 (EDT) To: "Hiroshi Inoue" cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> References: <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> Comments: In-reply-to "Hiroshi Inoue" message dated "Thu, 22 Jun 2000 10:15:01 +0900" Date: Wed, 21 Jun 2000 23:27:10 -0400 Message-ID: <7153.961644430@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Hiroshi Inoue" writes: > Please add my opinion to the list. > Unique-id filename: Hiroshi > (Unqiue-id is irrelevant to OID/relname). "Unique ID" is more or less equivalent to "OID + version number", right? I was trying earlier to convince myself that a single unique-ID value would be better than OID+version for the smgr interface, because it'd certainly be easier to pass around. I failed to convince myself though, and the thing that bothered me was this. Suppose you are trying to recover a corrupted database manually, and the only information you have about which table is which is a somewhat out-of-date listing of OIDs versus table names. (Maybe it's out of date because you got it from your last backup tape.) If the files are named OID+version you're not going to have much trouble seeing which is which, even if some of the versions are higher than what was on the tape. But if version-updated tables are given entirely new unique IDs, you've got no hope at all of telling which one corresponds to what you had in the listing. Maybe you can tell by looking through the physical file contents, but certainly this way is more fragile from the point of view of data recovery. regards, tom lane From tgl@sss.pgh.pa.us Thu Jun 22 01:01:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA22232; Thu, 22 Jun 2000 01:00:59 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id AAA17842; Thu, 22 Jun 2000 00:31:06 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id AAA07254; Thu, 22 Jun 2000 00:29:42 -0400 (EDT) To: "Hiroshi Inoue" cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "Bruce Momjian" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <000201bfdbd9$b1985580$2801007e@tpf.co.jp> References: <000201bfdbd9$b1985580$2801007e@tpf.co.jp> Comments: In-reply-to "Hiroshi Inoue" message dated "Thu, 22 Jun 2000 08:37:42 +0900" Date: Thu, 22 Jun 2000 00:29:42 -0400 Message-ID: <7251.961648182@sss.pgh.pa.us> From: Tom Lane Status: RO "Hiroshi Inoue" writes: > I strongly object to keep tablespace OID for smgr file reference token > though we have to keep it for another purpose of cource. I've mentioned > many times tablespace(where to store) info should be distinguished from > *where it is stored* info. Sure. But this proposal assumes that we're relying on symlinks to carry the information about physical locations corresponding to tablespace OIDs. The backend just needs to know enough to access a relation file at a relative pathname like tablespaceOID/relationOID (ignoring version and segment numbers for now). Under the hood, a symlink for tablespaceOID gets the work done. Certainly this is not a perfect mechanism. But it is simple, it is reliable, it is portable to most of the platforms we care about (yeah, I know we have a Win port, but you wouldn't ever recommend someone to run a *serious* database on it would you?), and in general I think the bang-for-the-buck ratio is enormous. I do not want to have to deal with explicit tablespace bookkeeping in the backend, but that seems like what we'd have to do in order to improve on symlinks. regards, tom lane From pgsql-hackers-owner+M3720@hub.org Thu Jun 22 02:01:02 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA24025 for ; Thu, 22 Jun 2000 02:01:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA21392 for ; Thu, 22 Jun 2000 01:56:49 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5M5jp143149; Thu, 22 Jun 2000 01:45:51 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by hub.org (8.10.1/8.10.1) with ESMTP id e5M5jT143025 for ; Thu, 22 Jun 2000 01:45:29 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id WAA11735; Wed, 21 Jun 2000 22:44:28 -0700 (PDT) Message-Id: <3.0.1.32.20000621224122.035b8c80@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Wed, 21 Jun 2000 22:41:22 -0700 To: Chris Bitmead , Bruce Momjian From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: PostgreSQL-development In-Reply-To: <39518B7C.F76108FD@nimrod.itg.telecom.com.au> References: <200006220229.WAA08130@candle.pha.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO At 01:43 PM 6/22/00 +1000, Chris Bitmead wrote: >I'm wondering if pg_dump should store the location of the tablespace. If >your machine dies, you get a new machine to re-create the database, you >may not want the tablespace in the same spot. And text-editing a >gigabyte file would be extremely painful. So you don't dump your create tablespace statements, recognizing that on a new machine (due to upgrades or crashing) you might assign them to different directories/mount points/whatever. That's the reason for wanting to hide physical allocation in tablespaces ... the rest of your datamodel doesn't need to know. Or you do dump your tablespaces, and knowing the paths assigned to various ones set up your new machine accordingly. - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From dhogaza@pacifier.com Thu Jun 22 02:00:58 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA24005 for ; Thu, 22 Jun 2000 02:00:58 -0400 (EDT) Received: from smtp.pacifier.com (comet.pacifier.com [199.2.117.155]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA21369 for ; Thu, 22 Jun 2000 01:56:18 -0400 (EDT) Received: from desktop (dsl-dhogaza.pacifier.net [207.202.226.68]) by smtp.pacifier.com (8.9.3/8.9.3pop) with SMTP id WAA12121; Wed, 21 Jun 2000 22:55:39 -0700 (PDT) Message-Id: <3.0.1.32.20000621225149.035bc070@mail.pacifier.com> X-Sender: dhogaza@mail.pacifier.com X-Mailer: Windows Eudora Pro Version 3.0.1 (32) Date: Wed, 21 Jun 2000 22:51:49 -0700 To: Bruce Momjian , Chris Bitmead From: Don Baccus Subject: Re: [HACKERS] Big 7.1 open items Cc: PostgreSQL-development In-Reply-To: <200006220403.AAA15648@candle.pha.pa.us> References: <39518B7C.F76108FD@nimrod.itg.telecom.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 12:03 AM 6/22/00 -0400, Bruce Momjian wrote: >If the symlink create fails in CREATE TABLESPACE, it just creates an >ordinary directory. Silent surprises - the earmark of truly professional software ... - Don Baccus, Portland OR Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net. From Inoue@tpf.co.jp Thu Jun 22 02:01:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id CAA24009 for ; Thu, 22 Jun 2000 02:00:59 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id BAA21277 for ; Thu, 22 Jun 2000 01:54:44 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id OAA03303; Thu, 22 Jun 2000 14:53:52 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 14:56:07 +0900 Message-ID: <000901bfdc0e$8f32fec0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <7251.961648182@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > "Hiroshi Inoue" writes: > > I strongly object to keep tablespace OID for smgr file reference token > > though we have to keep it for another purpose of cource. I've mentioned > > many times tablespace(where to store) info should be distinguished from > > *where it is stored* info. > > Sure. But this proposal assumes that we're relying on symlinks to > carry the information about physical locations corresponding to > tablespace OIDs. The backend just needs to know enough to access a > relation file at a relative pathname like > tablespaceOID/relationOID > (ignoring version and segment numbers for now). Under the hood, > a symlink for tablespaceOID gets the work done. > I think tablespaceOID is an easy substitution for the purpose. I don't like to depend on poor directory tree structure in dbms either.. > Certainly this is not a perfect mechanism. But it is simple, it > is reliable, it is portable to most of the platforms we care about > (yeah, I know we have a Win port, but you wouldn't ever recommend > someone to run a *serious* database on it would you?), and in general > I think the bang-for-the-buck ratio is enormous. I do not want to > have to deal with explicit tablespace bookkeeping in the backend, > but that seems like what we'd have to do in order to improve on > symlinks. > I've already mentioned about it 10 times or so but unfortunately I see no one on my side yet. OK,I've given up the discussion about it. I don't want to waste my time any more. Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Thu Jun 22 03:31:04 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA28813 for ; Thu, 22 Jun 2000 03:31:03 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA23901 for ; Thu, 22 Jun 2000 03:06:47 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id DAA07725; Thu, 22 Jun 2000 03:05:00 -0400 (EDT) To: Chris Bitmead cc: Bruce Momjian , PostgreSQL-development Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <39518B7C.F76108FD@nimrod.itg.telecom.com.au> References: <200006220229.WAA08130@candle.pha.pa.us> <39518B7C.F76108FD@nimrod.itg.telecom.com.au> Comments: In-reply-to Chris Bitmead message dated "Thu, 22 Jun 2000 13:43:56 +1000" Date: Thu, 22 Jun 2000 03:05:00 -0400 Message-ID: <7722.961657500@sss.pgh.pa.us> From: Tom Lane Status: RO Chris Bitmead writes: > I'm wondering if pg_dump should store the location of the tablespace. If > your machine dies, you get a new machine to re-create the database, you > may not want the tablespace in the same spot. And text-editing a > gigabyte file would be extremely painful. Might make sense to store the tablespace setup separately from the bulk of the data, but certainly you want some way to dump that info in a restorable form. I've been thinking lately that the pg_dump shove-it-all-in-one-file approach doesn't scale anyway. We ought to start thinking about ways to make the standard dump method store schema separately from bulk data, for example. That's offtopic for this thread but ought to be on the TODO list someplace... regards, tom lane From pgsql-hackers-owner+M3727@hub.org Thu Jun 22 03:31:06 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA28819 for ; Thu, 22 Jun 2000 03:31:05 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA24751 for ; Thu, 22 Jun 2000 03:29:00 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5M7KP140211; Thu, 22 Jun 2000 03:20:25 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5M7Jb139991 for ; Thu, 22 Jun 2000 03:19:37 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id DAA07785; Thu, 22 Jun 2000 03:17:45 -0400 (EDT) To: "Philip J. Warner" cc: "Hiroshi Inoue" , "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <3.0.5.32.20000622163133.009b1600@mail.rhyme.com.au> References: <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> <3.0.5.32.20000622163133.009b1600@mail.rhyme.com.au> Comments: In-reply-to "Philip J. Warner" message dated "Thu, 22 Jun 2000 16:31:33 +1000" Date: Thu, 22 Jun 2000 03:17:45 -0400 Message-ID: <7782.961658265@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Philip J. Warner" writes: >> ... the thing that bothered me was this. Suppose you are trying to >> recover a corrupted database manually, and the only information you have >> about which table is which is a somewhat out-of-date listing of OIDs >> versus table names. > This worries me a little; in the Dec/RDB world it is a very long time since > database backups were done by copying the files. There is a database > backup/restore utility which runs while the database is on-line and makes > sure a valid snapshot is taken. Backing up storage areas (table spapces) > can be done separately by the same utility, and again, it records enough > information to ensure integrity. Maybe the thing to do is write a pg_backup > utility, which in a first pass could, presumably, be synonymous with pg_dump? pg_dump already does the consistent-snapshot trick (it just has to run inside a single transaction). > Am I missing something here? Is there a problem with backing up using > 'pg_dump | gzip'? None, as long as your ambition extends no further than restoring your data to where it was at your last pg_dump. I was thinking about the all-too-common-in-the-real-world scenario where you're hoping to recover some data more recent than your last backup from the fractured shards of your database... regards, tom lane From zeugswettera@wien.spardat.at Thu Jun 22 05:01:11 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id FAA29525 for ; Thu, 22 Jun 2000 05:01:09 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id EAA27070 for ; Thu, 22 Jun 2000 04:38:32 -0400 (EDT) Received: from peligor.server.lan.at (peligor.server.lan.at [10.8.32.84]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id KAA23252; Thu, 22 Jun 2000 10:37:45 +0200 Received: from zeus (totalctlh1-port029.f000.d0188.sd.spardat.at [10.8.35.226]) by peligor.server.lan.at (8.9.1/8.9.1) with SMTP id KAA02457; Thu, 22 Jun 2000 10:41:04 GMT From: Zeugswetter Andreas SB To: Chris Bitmead , Bruce Momjian Subject: Re: Big 7.1 open items Date: Thu, 22 Jun 2000 09:49:07 +0200 X-Mailer: KMail [version 1.0.29.1] Content-Type: text/plain Cc: PostgreSQL-development References: <200006220229.WAA08130@candle.pha.pa.us> <39518B7C.F76108FD@nimrod.itg.telecom.com.au> In-Reply-To: <39518B7C.F76108FD@nimrod.itg.telecom.com.au> MIME-Version: 1.0 Message-Id: <00062210055400.00299@zeus> Content-Transfer-Encoding: 8bit Status: RO > > pg_dump would recreate a CREATE TABLESPACE command: > > > > printf("CREATE TABLESPACE %s USING %s", loc, symloc); > > > > where symloc would be SELECT symloc(loc) and return the value into a > > variable that is used by pg_dump. The backend would do the lstat() and > > return the value to the client. > > I'm wondering if pg_dump should store the location of the tablespace. If > your machine dies, you get a new machine to re-create the database, you > may not want the tablespace in the same spot. And text-editing a > gigabyte file would be extremely painful. Yes, that seems like a valid concern that should be kept in mind. It should also be possible to restore a pg instance to a different location on the same machine. Maybe this could be done by adding a utility that dumps all tablespace info which could then be altered to desire. I still opt for instance-wide tablespaces. People wanting separation can easily create different tablespaces for each database, but those that only want to separate data and index need only create two tablespaces. A typical installation would have 1 to 4 tablespaces (systemtbs, datatbs, indextbs, toasttbs | lobdbs ) I would also switch the directory structure between dbname and extent subdir, because that allows less symlinks/filesystems, and thus less admin. thus you would have: tablespace1/extent1/dbname1 tablespace1/extent2/dbname1 tablespace1/extent1/dbname2 Andreas From pjw@rhyme.com.au Thu Jun 22 04:01:05 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA29060 for ; Thu, 22 Jun 2000 04:01:03 -0400 (EDT) Received: from acheron.rime.com.au (root@albatr.lnk.telstra.net [139.130.54.222]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id DAA25604 for ; Thu, 22 Jun 2000 03:50:30 -0400 (EDT) Received: from oberon (Oberon.rime.com.au [203.8.195.100]) by acheron.rime.com.au (8.9.3/8.9.3) with SMTP id RAA08811; Thu, 22 Jun 2000 17:43:22 +1000 Message-Id: <3.0.5.32.20000622175015.00a10160@mail.rhyme.com.au> X-Sender: pjw@mail.rhyme.com.au X-Mailer: QUALCOMM Windows Eudora Pro Version 3.0.5 (32) Date: Thu, 22 Jun 2000 17:50:15 +1000 To: Tom Lane From: "Philip J. Warner" Subject: Re: [HACKERS] Big 7.1 open items Cc: "Hiroshi Inoue" , "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" In-Reply-To: <7782.961658265@sss.pgh.pa.us> References: <3.0.5.32.20000622163133.009b1600@mail.rhyme.com.au> <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> <000501bfdbe7$49fcdd20$2801007e@tpf.co.jp> <3.0.5.32.20000622163133.009b1600@mail.rhyme.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Status: RO At 03:17 22/06/00 -0400, Tom Lane wrote: > >> This worries me a little; in the Dec/RDB world it is a very long time since >> database backups were done by copying the files. There is a database >> backup/restore utility which runs while the database is on-line and makes >> sure a valid snapshot is taken. Backing up storage areas (table spapces) >> can be done separately by the same utility, and again, it records enough >> information to ensure integrity. Maybe the thing to do is write a pg_backup >> utility, which in a first pass could, presumably, be synonymous with pg_dump? > >pg_dump already does the consistent-snapshot trick (it just has to run >inside a single transaction). > >> Am I missing something here? Is there a problem with backing up using >> 'pg_dump | gzip'? > >None, as long as your ambition extends no further than restoring your >data to where it was at your last pg_dump. I was thinking about the >all-too-common-in-the-real-world scenario where you're hoping to recover >some data more recent than your last backup from the fractured shards >of your database... > pg_dump is a good basis for any pg_backup utility; perhaps as you indicated elsewhere, more carefull formatting of the dump files would make table-based restoration possible. In another response, I also suggested allowing overrides of placement information in a restore operation- the simplest approach would be an 'ignore-storage-parameters' flag. Does this sound reasonable? If so, then discussion of file-id based on OID needs not be too concerned about how db restoration is done. ---------------------------------------------------------------- Philip Warner | __---_____ Albatross Consulting Pty. Ltd. |----/ - \ (A.C.N. 008 659 498) | /(@) ______---_ Tel: (+61) 0500 83 82 81 | _________ \ Fax: (+61) 0500 83 82 82 | ___________ | Http://www.rhyme.com.au | / \| | --________-- PGP key available upon request, | / and from pgp5.ai.mit.edu:11371 |/ From pgsql-hackers-owner+M3730@hub.org Thu Jun 22 05:31:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id FAA29741 for ; Thu, 22 Jun 2000 05:31:00 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id FAA28478 for ; Thu, 22 Jun 2000 05:18:37 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5M96W171286; Thu, 22 Jun 2000 05:06:32 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5M96A168442 for ; Thu, 22 Jun 2000 05:06:10 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id SAA03635; Thu, 22 Jun 2000 18:05:02 +0900 From: "Hiroshi Inoue" To: "Peter Eisentraut" Cc: "Tom Lane" , "Bruce Momjian" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 18:07:18 +0900 Message-ID: <000c01bfdc29$43f717a0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Peter Eisentraut [mailto:e99re41@DoCS.UU.SE] > > > My opinion > > 3) database and tablespace are relatively irrelevant. > > I assume PostgreSQL's database would correspond > > to the concept of SCHEMA. > > A database corresponds to a catalog and a schema corresponds to nothing > yet. > Oh I see your point. However I've thought that current PostgreSQL's database is an imcomplete SCHEMA and still feel so in reality. Catalog per database has been nothing but needless for me from the first. Regards. Hiroshi Inoue Inoue@tpf.co.jp From Inoue@tpf.co.jp Thu Jun 22 07:31:01 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id HAA07559 for ; Thu, 22 Jun 2000 07:31:00 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id HAA02741 for ; Thu, 22 Jun 2000 07:08:29 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id UAA03834; Thu, 22 Jun 2000 20:06:51 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 20:09:07 +0900 Message-ID: <000d01bfdc3a$48fb35e0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 Importance: Normal In-Reply-To: <7153.961644430@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Status: RO > -----Original Message----- > From: Tom Lane [mailto:tgl@sss.pgh.pa.us] > > "Hiroshi Inoue" writes: > > Please add my opinion to the list. > > Unique-id filename: Hiroshi > > (Unqiue-id is irrelevant to OID/relname). > > "Unique ID" is more or less equivalent to "OID + version number", > right? > Hmm,no one seems to be on my side at this point also. OK,I change my mind as follows. OID except cygwin,unique-id on cygwin Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Thu Jun 22 11:31:06 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA10544 for ; Thu, 22 Jun 2000 11:31:05 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id LAA23513 for ; Thu, 22 Jun 2000 11:28:53 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id LAA08851; Thu, 22 Jun 2000 11:27:30 -0400 (EDT) To: "Hiroshi Inoue" cc: "Bruce Momjian" , "Peter Eisentraut" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" , "Thomas Lockhart" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <000d01bfdc3a$48fb35e0$2801007e@tpf.co.jp> References: <000d01bfdc3a$48fb35e0$2801007e@tpf.co.jp> Comments: In-reply-to "Hiroshi Inoue" message dated "Thu, 22 Jun 2000 20:09:07 +0900" Date: Thu, 22 Jun 2000 11:27:30 -0400 Message-ID: <8848.961687650@sss.pgh.pa.us> From: Tom Lane Status: RO "Hiroshi Inoue" writes: > OK,I change my mind as follows. > OID except cygwin,unique-id on cygwin We don't really want to do that, do we? That's a huge difference in behavior to have in just one port --- especially a port that none of the primary developers use (AFAIK anyway). The cygwin port's normal state of existence will be "broken", surely, if we go that way. Besides which, OID alone doesn't give us a possibility of file versioning, and as I commented to Vadim I think we will want that, WAL or no WAL. So it seems to me the two viable choices are unique-id or OID+version-number. Either way, the file-naming behavior should be the same across all platforms. regards, tom lane From vmikheev@SECTORBASE.COM Thu Jun 22 14:31:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA11892 for ; Thu, 22 Jun 2000 14:30:59 -0400 (EDT) Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id OAA10107 for ; Thu, 22 Jun 2000 14:17:04 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Thu, 22 Jun 2000 11:07:59 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C31@SECTORBASE1> From: "Mikheev, Vadim" To: "'Tom Lane'" Cc: Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Thu, 22 Jun 2000 11:09:47 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: RO > > I believe that we can avoid versions using WAL... > > I don't think so. You're basically saying that > 1. create file 'new' > 2. delete file 'old' > 3. rename 'new' to 'old' > is safe as long as you have a redo log to ensure that the rename > happens even if you crash between steps 2 and 3. But crash is not > the only hazard. What if step 3 just plain fails? Redo won't help. Ok, ok. Let's use *unique* file name for each table version. But after thinking, seems that I agreed with Hiroshi about using *some unique id* for file names instead of oid+version: we could use just DB' OID + this unique ID in log records to find table file - just 8 bytes. So, add me to Hiroshi' camp... if Hiroshi is ready to implement new file naming -:) > > But what about LOCATIONs? I object using environment and think that > > locations must be stored in pg_control..? > > I don't like environment variables for this either; it's just way too > easy to start the postmaster with wrong environment. It still seems > to me that relying on subdirectory symlinks is a good way to go. I always thought so. > pg_control is not so good --- if it gets corrupted, how do > you recover? Impossible to recover anyway - pg_control keeps last checkpoint pointer, required for recovery. That's why Oracle recommends (requires?) at least two copies of control file (and log too). But what if log gets corrupted? Or file system (lost symlinks etc)? One will have to use backup... Vadim From peter@localhost.its.uu.se Thu Jun 22 18:37:35 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id SAA19684 for ; Thu, 22 Jun 2000 18:37:34 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id SAA02841 for ; Thu, 22 Jun 2000 18:31:53 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:37596 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Fri, 23 Jun 2000 00:29:48 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 135FaG-00062q-00; Fri, 23 Jun 2000 00:36:28 +0200 Date: Fri, 23 Jun 2000 00:36:28 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: Hiroshi Inoue , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <8803.961687343@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: Peter Eisentraut Status: RO Tom Lane writes: > In my mind the point of the "database" concept is to provide a domain > within which custom datatypes and functions are available. Quoth SQL99: "A user-defined type is a schema object" "An SQL-invoked routine is an element of an SQL-schema" I have yet to see anything in SQL that's a per-catalog object. Some things are global, like users, but everything else is per-schema. The way I see it is that schemas are required to be a logical hierarchy, whereas implementations may see catalogs as a physical division (as indeed this implementation does). > So I think we will still want "database" = "span of applicability of > system catalogs" Yes, because the system catalogs would live in a schema of their own. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From ZeugswetterA@wien.spardat.at Mon Jun 26 04:10:01 2000 Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA29267 for ; Mon, 26 Jun 2000 04:09:59 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id KAA35550; Mon, 26 Jun 2000 10:09:14 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 26 Jun 2000 10:09:14 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA598B@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" , Hiroshi Inoue Cc: Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" , Thomas Lockhart Subject: [HACKERS] File versioning (was: Big 7.1 open items) Date: Mon, 26 Jun 2000 10:09:13 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Status: RO > Besides which, OID alone doesn't give us a possibility of file > versioning, and as I commented to Vadim I think we will want that, > WAL or no WAL. So it seems to me the two viable choices are > unique-id or OID+version-number. Either way, the file-naming behavior > should be the same across all platforms. I do not think the only problem of a failing rename of "temp" to "new" on startup rollforward is issue enough to justify the additional complexity a version implys. Why not simply abort startup of postmaster in such an event and let the dba fix it. There can be no data loss. If e.g. the permissions of the directory are insufficient we will want to abort startup anyway, no? Andreas From ZeugswetterA@wien.spardat.at Mon Jun 26 05:32:05 2000 Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id FAA29616 for ; Mon, 26 Jun 2000 05:32:03 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id LAA27288; Mon, 26 Jun 2000 11:31:08 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 26 Jun 2000 11:31:08 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA598F@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Hiroshi Inoue'" , Peter Eisentraut , Tom Lane Cc: Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 11:31:06 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Status: RO > > > In my mind the point of the "database" concept is to > provide a domain > > > within which custom datatypes and functions are available. > > > > AFAIK few users understand it and many users have wondered > why we couldn't issue cross "database" queries. Imho the same issue is access to tables on another machine. If we "fix" that, access to another db on the same instance is just a variant of the above. > > > Quoth SQL99: > > > > "A user-defined type is a schema object" > > > > "An SQL-invoked routine is an element of an SQL-schema" > > > > I have yet to see anything in SQL that's a per-catalog > object. Some things > > are global, like users, but everything else is per-schema. Yes. > So why is system catalog needed per "database" ? I like to use different databases on a development machine, because it makes testing easier. The only thing that needs to be changed is the connect statement. All other statements including schema qualified tablenames stay exactly the same for each developer even though each has his own database, and his own version of functions. I have yet to see an installation that does'nt have at least one program that needs access to more than one schema. On production machines we (using Informix) use different databases for different products, because it reduces the possibility of accessing the wrong tables, since the syntax for accessing tables in other db's is different (dbname[@instancename]:"owner".tabname in Informix) The schema does not help us, since most of our programs access tables from more than one schema. And again someone wanting Oracle'ish behavior will only create one database per instance. Andreas From pgsql-hackers-owner+M4088@hub.org Mon Jul 3 01:57:49 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id BAA08810 for ; Mon, 3 Jul 2000 01:57:49 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e635u5S69222; Mon, 3 Jul 2000 01:56:05 -0400 (EDT) Received: from po.seiren.co.jp (po.seiren.co.jp [203.138.223.10]) by hub.org (8.10.1/8.10.1) with ESMTP id e5QA5d124120 for ; Mon, 26 Jun 2000 06:05:41 -0400 (EDT) Received: from mcadnote1 ([210.161.188.23]) by po.seiren.co.jp (post.office MTA v1.9.3 ID# 0100012-16224) with SMTP id AAA59; Mon, 26 Jun 2000 19:04:51 +0900 From: "Hiroshi Inoue" To: "Zeugswetter Andreas SB" , "Peter Eisentraut" , "Tom Lane" Cc: "Bruce Momjian" , "Jan Wieck" , "PostgreSQL-development" , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 19:08:26 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal In-Reply-To: <219F68D65015D011A8E000006F8590C605BA598F@sdexcsrv1.f000.d0188.sd.spardat.at> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: Zeugswetter Andreas SB > > > > > In my mind the point of the "database" concept is to > > provide a domain > > > > within which custom datatypes and functions are available. > > > > > > > AFAIK few users understand it and many users have wondered > > why we couldn't issue cross "database" queries. > > Imho the same issue is access to tables on another machine. > If we "fix" that, access to another db on the same instance is just > a variant of the above. > What is a difference between SCHAMA and your "database" ? I myself am confused about them. Regards. Hiroshi Inoue Inoue@tpf.co.jp From ZeugswetterA@wien.spardat.at Mon Jun 26 06:50:26 2000 Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id GAA07354 for ; Mon, 26 Jun 2000 06:50:24 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id MAA41146; Mon, 26 Jun 2000 12:50:11 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 26 Jun 2000 12:50:11 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA5991@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Hiroshi Inoue'" , Peter Eisentraut , Tom Lane Cc: Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 12:50:10 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="windows-1252" Status: RO Hiroshi Inoue [mailto:Inoue@seiren.co.jp] wrote: > > > > > In my mind the point of the "database" concept is to > > > provide a domain > > > > > within which custom datatypes and functions are available. > > > > > > > > > > AFAIK few users understand it and many users have wondered > > > why we couldn't issue cross "database" queries. > > > > Imho the same issue is access to tables on another machine. > > If we "fix" that, access to another db on the same instance is just > > a variant of the above. > > > > What is a difference between SCHAMA and your "database" ? > I myself am confused about them. Think of it as a hierarchy: instance -> database -> schema -> object - "instance" corresponds to one postmaster - "database" as in current implementation - "schema" name corresponds to the owner of the object, only that a corresponding db or os user does not need to exist in some of the implementations I know. - "object" is one of table, index, function ... The database is what you connect to in your connect statement, you then see all schemas inside this database only. Access to another database would need an explicitly created synonym or different syntax. The default "schema" name is usually the logged in user name (although I don't like this approach, I like Informix's approach where the schema need not be specified if tabname is unique (and tabname is unique per db unless you specify database mode ansi)). All other schemas have to be explicitly named ("schemaname".tabname). Oracle has exactly this layout, only you are restricted to one database per instance. (They even have a "create database .." statement, although it is somehow analogous to our initdb). Andreas From ZeugswetterA@wien.spardat.at Mon Jun 26 07:51:14 2000 Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id HAA07648 for ; Mon, 26 Jun 2000 07:51:12 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id NAA40848; Mon, 26 Jun 2000 13:50:56 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 26 Jun 2000 13:50:55 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA5993@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Mikheev, Vadim'" , "'Tom Lane'" Cc: Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 13:50:55 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Status: RO Vadim wrote: > Impossible to recover anyway - pg_control keeps last > checkpoint pointer, required for recovery. Why not put this info in the tx log itself. > That's why Oracle recommends (requires?) at least > two copies of control file .... This is one of the most stupid design issues Oracle has. I suggest you look at the tx log design of Informix. (No Informix dba fears to pull the power cord on his servers, ask the same of an Oracle dba, they even fear "shutdown immediate" on a heavily used db) Andreas From ZeugswetterA@wien.spardat.at Mon Jun 26 08:02:07 2000 Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id IAA07760 for ; Mon, 26 Jun 2000 08:02:05 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id OAA74134; Mon, 26 Jun 2000 14:01:17 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 26 Jun 2000 14:01:17 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA5994@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: Zeugswetter Andreas SB , "'Mikheev, Vadim'" , "'Tom Lane'" Cc: Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , Hiroshi Inoue , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 14:01:15 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Status: RO I wrote: > Vadim wrote: > > Impossible to recover anyway - pg_control keeps last > > checkpoint pointer, required for recovery. > > Why not put this info in the tx log itself. > > > That's why Oracle recommends (requires?) at least > > two copies of control file .... > > This is one of the most stupid design issues Oracle has. The problem is, that if you want to switch to a no fsync environment, (here I also mean the tx log) but the possibility of losing a write is still there, you cannot sync writes to two or more different files. Only one file, the tx log itself is allowed to carry lastminute information. Thus you need to txlog changes to pg_control also. Andreas From tgl@sss.pgh.pa.us Mon Jun 26 10:42:08 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA11148 for ; Mon, 26 Jun 2000 10:42:06 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id KAA17018; Mon, 26 Jun 2000 10:42:31 -0400 (EDT) To: Zeugswetter Andreas SB cc: Hiroshi Inoue , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" , Thomas Lockhart Subject: Re: [HACKERS] File versioning (was: Big 7.1 open items) In-reply-to: <219F68D65015D011A8E000006F8590C605BA598B@sdexcsrv1.f000.d0188.sd.spardat.at> References: <219F68D65015D011A8E000006F8590C605BA598B@sdexcsrv1.f000.d0188.sd.spardat.at> Comments: In-reply-to Zeugswetter Andreas SB message dated "Mon, 26 Jun 2000 10:09:13 +0200" Date: Mon, 26 Jun 2000 10:42:31 -0400 Message-ID: <17015.962030551@sss.pgh.pa.us> From: Tom Lane Status: RO Zeugswetter Andreas SB writes: > I do not think the only problem of a failing rename of "temp" to "new" > on startup rollforward is issue enough to justify the additional complexity > a version implys. If that were the only reason for it then I wouldn't feel it was so essential. However, it will also let us fix CLUSTER, vacuuming of indexes, ALTER TABLE DROP COLUMN with physical removal of the column, etc etc. Making the world safe for rollbackable RENAME/DROP/TRUNCATE TABLE is just one of the benefits. Versioning also eliminates a whole host of problems at the bufmgr/smgr level that are caused by having to cope with relation files getting renamed out from under you. We have painfully eliminated some of these problems over the past couple of years by ad-hoc, ugly techniques like flushing the buffer cache when doing a rename. But who's to say there are not more such bugs left? In short, I think versioning is far *less* complex, not to mention more reliable, than the kluges we need to use to work around the lack of it. regards, tom lane From pgsql-hackers-owner+M3879@hub.org Mon Jun 26 18:30:55 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id SAA02022 for ; Mon, 26 Jun 2000 18:30:54 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5QMMa123238; Mon, 26 Jun 2000 18:22:37 -0400 (EDT) Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by hub.org (8.10.1/8.10.1) with ESMTP id e5QMMJ123161 for ; Mon, 26 Jun 2000 18:22:19 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Mon, 26 Jun 2000 15:13:48 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C36@SECTORBASE1> From: "Mikheev, Vadim" To: "'Tom Lane'" Cc: "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 15:15:39 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > > Do we need *both* database & tablespace to find table file ?! > > Imho, database shouldn't be used... > > That'd work fine for me, but I think Bruce was arguing for paths that > included the database name. We'd end up with paths that go something > like > ..../data/tablespaces/TABLESPACEOID/RELATIONOID > (plus some kind of decoration for segment and version), so you'd have > a hard time telling which files in a tablespace belong to which > database. Doesn't bother me a whole lot, personally --- if one wants We could create /data/databases/DATABASEOID/ and create soft-links to table-files. This way different tables of the same database could be in different tablespaces. /data/database path would be used in production and /data/tablespace path would be used in recovery. Vadim From vmikheev@SECTORBASE.COM Mon Jun 26 18:21:53 2000 Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id SAA01888 for ; Mon, 26 Jun 2000 18:21:52 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Mon, 26 Jun 2000 15:13:48 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C36@SECTORBASE1> From: "Mikheev, Vadim" To: "'Tom Lane'" Cc: "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 15:15:39 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: RO > > Do we need *both* database & tablespace to find table file ?! > > Imho, database shouldn't be used... > > That'd work fine for me, but I think Bruce was arguing for paths that > included the database name. We'd end up with paths that go something > like > ..../data/tablespaces/TABLESPACEOID/RELATIONOID > (plus some kind of decoration for segment and version), so you'd have > a hard time telling which files in a tablespace belong to which > database. Doesn't bother me a whole lot, personally --- if one wants We could create /data/databases/DATABASEOID/ and create soft-links to table-files. This way different tables of the same database could be in different tablespaces. /data/database path would be used in production and /data/tablespace path would be used in recovery. Vadim From tgl@sss.pgh.pa.us Mon Jun 26 18:47:54 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id SAA02118 for ; Mon, 26 Jun 2000 18:47:52 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id SAA19579; Mon, 26 Jun 2000 18:48:22 -0400 (EDT) To: "Mikheev, Vadim" cc: "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <8F4C99C66D04D4118F580090272A7A23018C36@SECTORBASE1> References: <8F4C99C66D04D4118F580090272A7A23018C36@SECTORBASE1> Comments: In-reply-to "Mikheev, Vadim" message dated "Mon, 26 Jun 2000 15:15:39 -0700" Date: Mon, 26 Jun 2000 18:48:22 -0400 Message-ID: <19576.962059702@sss.pgh.pa.us> From: Tom Lane Status: RO "Mikheev, Vadim" writes: > We could create /data/databases/DATABASEOID/ and create soft-links to > table-files. This way different tables of the same database could be in > different tablespaces. /data/database path would be used in production > and /data/tablespace path would be used in recovery. Why would you want to do it that way? Having a different access path for recovery than for normal operation strikes me as just asking for trouble ;-) The symlinks wouldn't do any good for what Bruce had in mind anyway (IIRC, he wanted to get useful per-database numbers from "du"). regards, tom lane From pgsql-hackers-owner+M3888@hub.org Mon Jun 26 23:37:52 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id XAA04481 for ; Mon, 26 Jun 2000 23:37:51 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5R1nx169365; Mon, 26 Jun 2000 21:50:00 -0400 (EDT) Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by hub.org (8.10.1/8.10.1) with ESMTP id e5R1mt169094 for ; Mon, 26 Jun 2000 21:48:55 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Mon, 26 Jun 2000 18:40:19 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C38@SECTORBASE1> From: "Mikheev, Vadim" To: "'Tom Lane'" Cc: "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Mon, 26 Jun 2000 18:42:10 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > > We could create /data/databases/DATABASEOID/ and create > > soft-links to table-files. This way different tables of > > the same database could be in different tablespaces. > > /data/database path would be used in production > > and /data/tablespace path would be used in recovery. > > Why would you want to do it that way? Having a different access path > for recovery than for normal operation strikes me as just asking for > trouble ;-) I just think that *databases* (schemas) must be used for *logical* groupping of tables, not for *physical* one. "Where to store table" is tablespace' related kind of things! > The symlinks wouldn't do any good for what Bruce had in mind anyway > (IIRC, he wanted to get useful per-database numbers from "du"). Imho, ability to put different tables/indices (of the same database) to different tablespaces (disks) is much more useful then ability to use du/ls for administration purposes -:) Also, I think that we *must* go away from OS' driven disk space allocation anyway. Currently, the way we extend table files breaks WAL rule (nothing must go to disk untill logged). + we have to move tuples from end of file to top to shrink relation - not perfect way to reuse empty space. +... +... +... Vadim From Inoue@tpf.co.jp Tue Jun 27 00:05:13 2000 Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA05264 for ; Tue, 27 Jun 2000 00:05:11 -0400 (EDT) Received: from tpf.co.jp ([126.0.1.56] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with ESMTP id NAA01123; Tue, 27 Jun 2000 13:04:26 +0900 Message-ID: <39582880.7565547@tpf.co.jp> Date: Tue, 27 Jun 2000 13:07:28 +0900 From: Hiroshi Inoue X-Mailer: Mozilla 4.73 [ja] (Windows NT 5.0; U) X-Accept-Language: ja MIME-Version: 1.0 To: Tom Lane CC: "Mikheev, Vadim" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <8F4C99C66D04D4118F580090272A7A23018C36@SECTORBASE1> <19576.962059702@sss.pgh.pa.us> Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Status: ROr Tom Lane wrote: > > The symlinks wouldn't do any good for what Bruce had in mind anyway > (IIRC, he wanted to get useful per-database numbers from "du"). Our database design seems to be in the opposite direction if it is restricted for the convenience of command calls. Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3892@hub.org Tue Jun 27 00:14:24 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA05478 for ; Tue, 27 Jun 2000 00:14:23 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5R46J182392; Tue, 27 Jun 2000 00:06:20 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5R466180629 for ; Tue, 27 Jun 2000 00:06:06 -0400 (EDT) Received: from tpf.co.jp ([126.0.1.56] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with ESMTP id NAA01123; Tue, 27 Jun 2000 13:04:26 +0900 Message-ID: <39582880.7565547@tpf.co.jp> Date: Tue, 27 Jun 2000 13:07:28 +0900 From: Hiroshi Inoue X-Mailer: Mozilla 4.73 [ja] (Windows NT 5.0; U) X-Accept-Language: ja MIME-Version: 1.0 To: Tom Lane CC: "Mikheev, Vadim" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <8F4C99C66D04D4118F580090272A7A23018C36@SECTORBASE1> <19576.962059702@sss.pgh.pa.us> Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Tom Lane wrote: > > The symlinks wouldn't do any good for what Bruce had in mind anyway > (IIRC, he wanted to get useful per-database numbers from "du"). Our database design seems to be in the opposite direction if it is restricted for the convenience of command calls. Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3905@hub.org Tue Jun 27 10:07:49 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA21305 for ; Tue, 27 Jun 2000 10:07:48 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5RDUh185923; Tue, 27 Jun 2000 09:30:43 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by hub.org (8.10.1/8.10.1) with ESMTP id e5RDTB183147 for ; Tue, 27 Jun 2000 09:29:12 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id PAA41830; Tue, 27 Jun 2000 15:27:07 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Tue, 27 Jun 2000 15:27:06 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA5999@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" , "Mikheev, Vadim" Cc: "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: [HACKERS] Big 7.1 open items Date: Tue, 27 Jun 2000 15:27:03 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > That'd work fine for me, but I think Bruce was arguing for paths that > included the database name. We'd end up with paths that go something > like > ..../data/tablespaces/TABLESPACEOID/RELATIONOID > (plus some kind of decoration for segment and version), so you'd have > a hard time telling which files in a tablespace belong to which > database. Well ,as long as we have the file per object layout it probably makes sense to have "speaking paths", But I see no real problem with: ..../data/tablespacename/dbname/RELATIONOID[.dat|.idx] RELATIONOID standing for whatever the consensus will be. I do not really see an argument for using a tablespaceoid instead of it's [maybe mangled] name. Andreas From pgsql-hackers-owner+M3912@hub.org Tue Jun 27 10:28:39 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA21468 for ; Tue, 27 Jun 2000 10:28:38 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5REOa111784; Tue, 27 Jun 2000 10:24:36 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5REOG109445 for ; Tue, 27 Jun 2000 10:24:16 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id KAA09575; Tue, 27 Jun 2000 10:23:48 -0400 (EDT) To: Zeugswetter Andreas SB cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: AW: [HACKERS] Big 7.1 open items In-reply-to: <219F68D65015D011A8E000006F8590C605BA5999@sdexcsrv1.f000.d0188.sd.spardat.at> References: <219F68D65015D011A8E000006F8590C605BA5999@sdexcsrv1.f000.d0188.sd.spardat.at> Comments: In-reply-to Zeugswetter Andreas SB message dated "Tue, 27 Jun 2000 15:27:03 +0200" Date: Tue, 27 Jun 2000 10:23:48 -0400 Message-ID: <9572.962115828@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Zeugswetter Andreas SB writes: > I do not really see an argument for using a tablespaceoid instead of > it's [maybe mangled] name. Eliminating filesystem-based restrictions on names, for one. For example we'd not have to forbid slashes and (probably) backquotes in tablespace names if we did this, and we'd not have to worry about filesystem-induced limits on name lengths. Renaming a tablespace would also be trivial instead of nigh impossible. It might be that using tablespace names as directory names is worth enough from the admin point of view to make the above restrictions acceptable. But it's a tradeoff, and not one with an obvious choice IMHO. regards, tom lane From vmikheev@SECTORBASE.COM Tue Jun 27 14:01:08 2000 Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA28715 for ; Tue, 27 Jun 2000 14:01:07 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Tue, 27 Jun 2000 10:53:03 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C39@SECTORBASE1> From: "Mikheev, Vadim" To: "'Bruce Momjian'" , Hiroshi Inoue Cc: Tom Lane , Thomas Lockhart , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Tue, 27 Jun 2000 10:54:55 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: ROr > > > The symlinks wouldn't do any good for what Bruce had in > > > mind anyway (IIRC, he wanted to get useful per-database > > > numbers from "du"). > > > > Our database design seems to be in the opposite direction > > if it is restricted for the convenience of command calls. > > Well, I don't see any reason not to use tablespace/database > rather than just tablespace. Seems having fewer files in each directory Once again - ability to use different tablespaces (disks) for tables/indices in the same schema. Schemas must not dictate where to store objects <- bad design. > will be a little faster, and if we can make administration easier, > why not? Because you'll not be able use du/ls once we'll implement new smgr anyway. And, btw, - for what are we going implement tablespaces? Just to have fewer files in each dir ?! Vadim From pgsql-hackers-owner+M3925@hub.org Tue Jun 27 14:03:35 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA28748 for ; Tue, 27 Jun 2000 14:03:34 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5RI1h139788; Tue, 27 Jun 2000 14:01:44 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by hub.org (8.10.1/8.10.1) with ESMTP id e5RI1I138791 for ; Tue, 27 Jun 2000 14:01:18 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:59174 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Tue, 27 Jun 2000 20:00:50 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 136zlm-0003zn-00; Tue, 27 Jun 2000 20:07:34 +0200 Date: Tue, 27 Jun 2000 20:07:34 +0200 (CEST) From: Peter Eisentraut To: "Mikheev, Vadim" cc: "'Hiroshi Inoue'" , "'Tom Lane'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items In-Reply-To: <8F4C99C66D04D4118F580090272A7A23018C35@SECTORBASE1> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Mikheev, Vadim writes: > Do we need *both* database & tablespace to find table file ?! > Imho, database shouldn't be used... Then the system tables from different databases would collide. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From vmikheev@SECTORBASE.COM Tue Jun 27 15:28:25 2000 Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id PAA04820 for ; Tue, 27 Jun 2000 15:28:24 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Tue, 27 Jun 2000 12:20:20 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C3A@SECTORBASE1> From: "Mikheev, Vadim" To: "'Bruce Momjian'" Cc: Hiroshi Inoue , Tom Lane , Thomas Lockhart , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Tue, 27 Jun 2000 12:22:13 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: ROr > > > Well, I don't see any reason not to use tablespace/database > > > rather than just tablespace. Seems having fewer files in > > > each directory > > > > Once again - ability to use different tablespaces (disks) > > for tables/indices in the same schema. Schemas must not dictate > > where to store objects <- bad design. > > I am suggesting this symlink: > > ln -s data/base/testdb/myspace /var/myspace/testdb > > rather than: > > ln -s data/base/testdb/myspace /var/myspace > > Tablespaces still sit inside database directories, it is just that it > points to a subdirectory of myspace, rather than myspace itself. ^^^^^^^^^^^ Didn't you mean ln -s /var/myspace/testdb data/base/testdb/myspace ? I thought that you don't like symlinks from data/base/... This is how I understood Tom' words: > The symlinks wouldn't do any good for what Bruce had in mind anyway > (IIRC, he wanted to get useful per-database numbers from "du"). Vadim From vmikheev@SECTORBASE.COM Tue Jun 27 15:43:31 2000 Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id PAA05148 for ; Tue, 27 Jun 2000 15:43:30 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Tue, 27 Jun 2000 12:35:41 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C3C@SECTORBASE1> From: "Mikheev, Vadim" To: "'Bruce Momjian'" Cc: "'Peter Eisentraut'" , "'Hiroshi Inoue'" , "'Tom Lane'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Tue, 27 Jun 2000 12:37:34 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: ROr > > > Then the system tables from different databases would collide. > > > > Actually, if we're going to use unique-ids for file names > > then we have to know how to get system file names anyway. > > Hm, OID+VERSION would make our life easier... Hiroshi? > > I assume we were going to have a pg_class.relversion to do that, but ^^^^^^^^ PG_CLASS_OID.VERSION_ID... Just a clarification -:) > that is per-database because pg_class is per-database. Vadim From vmikheev@SECTORBASE.COM Tue Jun 27 15:48:31 2000 Received: from sectorbase2.sectorbase.com ([208.48.122.131]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id PAA05452 for ; Tue, 27 Jun 2000 15:48:30 -0400 (EDT) Received: by SECTORBASE2 with Internet Mail Service (5.5.2650.21) id ; Tue, 27 Jun 2000 12:40:42 -0700 Message-ID: <8F4C99C66D04D4118F580090272A7A23018C3D@SECTORBASE1> From: "Mikheev, Vadim" To: "'Bruce Momjian'" Cc: "'Peter Eisentraut'" , "'Hiroshi Inoue'" , "'Tom Lane'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: RE: [HACKERS] Big 7.1 open items Date: Tue, 27 Jun 2000 12:42:35 -0700 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Status: ROr > I actually meant I thought we were going to have a pg_class column > called relversion that held the currently active version for that > relation. > > Yes, the file name will be pg_class_oid.version_id. > > Is that OK? We recently discussed pure *unique-id* file names... Vadim From pgsql-hackers-owner+M3939@hub.org Tue Jun 27 17:03:33 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA08565 for ; Tue, 27 Jun 2000 17:03:32 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5RL2B155891; Tue, 27 Jun 2000 17:02:11 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5RL10155419 for ; Tue, 27 Jun 2000 17:01:00 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id RAA11135; Tue, 27 Jun 2000 17:00:12 -0400 (EDT) To: Peter Eisentraut cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: References: Comments: In-reply-to Peter Eisentraut message dated "Tue, 27 Jun 2000 20:07:34 +0200" Date: Tue, 27 Jun 2000 17:00:11 -0400 Message-ID: <11132.962139611@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Peter Eisentraut writes: > Mikheev, Vadim writes: >> Do we need *both* database & tablespace to find table file ?! >> Imho, database shouldn't be used... > Then the system tables from different databases would collide. I've been assuming that we would create a separate tablespace for each database, which would be the location of that database's system tables. It's probably also the default tablespace for user tables created in that database, though it wouldn't have to be. There should also be a known tablespace for the installation-wide tables (pg_shadow et al). With this approach tablespace+relation would indeed be a sufficient identifier. We could even eliminate the knowledge that certain tables are installation-wide from the bufmgr and below (currently that knowledge is hardwired in places that I'd rather didn't know about it...) regards, tom lane From tgl@sss.pgh.pa.us Tue Jun 27 17:00:13 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA08435 for ; Tue, 27 Jun 2000 17:00:12 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id RAA11135; Tue, 27 Jun 2000 17:00:12 -0400 (EDT) To: Peter Eisentraut cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: References: Comments: In-reply-to Peter Eisentraut message dated "Tue, 27 Jun 2000 20:07:34 +0200" Date: Tue, 27 Jun 2000 17:00:11 -0400 Message-ID: <11132.962139611@sss.pgh.pa.us> From: Tom Lane Status: ROr Peter Eisentraut writes: > Mikheev, Vadim writes: >> Do we need *both* database & tablespace to find table file ?! >> Imho, database shouldn't be used... > Then the system tables from different databases would collide. I've been assuming that we would create a separate tablespace for each database, which would be the location of that database's system tables. It's probably also the default tablespace for user tables created in that database, though it wouldn't have to be. There should also be a known tablespace for the installation-wide tables (pg_shadow et al). With this approach tablespace+relation would indeed be a sufficient identifier. We could even eliminate the knowledge that certain tables are installation-wide from the bufmgr and below (currently that knowledge is hardwired in places that I'd rather didn't know about it...) regards, tom lane From tgl@sss.pgh.pa.us Tue Jun 27 17:18:49 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA09638 for ; Tue, 27 Jun 2000 17:18:48 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id RAA11377; Tue, 27 Jun 2000 17:19:31 -0400 (EDT) To: Bruce Momjian cc: "Mikheev, Vadim" , "'Peter Eisentraut'" , "'Hiroshi Inoue'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006271952.PAA05609@candle.pha.pa.us> References: <200006271952.PAA05609@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Tue, 27 Jun 2000 15:52:40 -0400" Date: Tue, 27 Jun 2000 17:19:31 -0400 Message-ID: <11374.962140771@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > Well, that would allow us to mix database files in the same directory, > if we wanted to do that. My opinion it is better to keep databases in > separate directories in each tablespace for clarity and performance > reasons. One reason not to do that is that we'd still have to special-case the system-wide relations. If it's just tablespace and OID in the path, then the system-wide rels look just the same as any other rel as far as the low-level stuff is concerned. That would be nice. My feeling about the "clarity and performance" issue is that if a dbadmin wants to keep track of database contents separately, he can put different databases' tables into different tablespaces to start with. If he puts several tables into one tablespace, he's saying he doesn't care about distinguishing their space usage. There's no reason for us to force an additional level of directory lookup to be done whether the admin wants it or not. regards, tom lane From tgl@sss.pgh.pa.us Tue Jun 27 17:29:35 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA09909 for ; Tue, 27 Jun 2000 17:29:33 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id RAA13026; Tue, 27 Jun 2000 17:30:18 -0400 (EDT) To: Bruce Momjian cc: "Mikheev, Vadim" , "'Peter Eisentraut'" , "'Hiroshi Inoue'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006272123.RAA09720@candle.pha.pa.us> References: <200006272123.RAA09720@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Tue, 27 Jun 2000 17:23:49 -0400" Date: Tue, 27 Jun 2000 17:30:17 -0400 Message-ID: <13018.962141417@sss.pgh.pa.us> From: Tom Lane Status: RO Bruce Momjian writes: > Yes, good point about pg_shadow. They don't have databases. How do we > get multiple pg_class tables in the same directory? Is the > pg_class.relversion file a number like 1,2,3,4, or does it come out of > some global counter like oid. If so, we could put them in the same > directory. I think we could get away with insisting that each database store its pg_class and friends in a separate tablespace (physically distinct directory) from any other database. That gets around the OID conflict. It's still an open question whether OID+version is better than unique-ID for naming files that belong to different versions of the same relation. I can see arguments on both sides. regards, tom lane From pgsql-hackers-owner+M3944@hub.org Tue Jun 27 17:33:05 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA09986 for ; Tue, 27 Jun 2000 17:33:04 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5RLV7124097; Tue, 27 Jun 2000 17:31:07 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5RLUn123949 for ; Tue, 27 Jun 2000 17:30:49 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id RAA13026; Tue, 27 Jun 2000 17:30:18 -0400 (EDT) To: Bruce Momjian cc: "Mikheev, Vadim" , "'Peter Eisentraut'" , "'Hiroshi Inoue'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006272123.RAA09720@candle.pha.pa.us> References: <200006272123.RAA09720@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Tue, 27 Jun 2000 17:23:49 -0400" Date: Tue, 27 Jun 2000 17:30:17 -0400 Message-ID: <13018.962141417@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Bruce Momjian writes: > Yes, good point about pg_shadow. They don't have databases. How do we > get multiple pg_class tables in the same directory? Is the > pg_class.relversion file a number like 1,2,3,4, or does it come out of > some global counter like oid. If so, we could put them in the same > directory. I think we could get away with insisting that each database store its pg_class and friends in a separate tablespace (physically distinct directory) from any other database. That gets around the OID conflict. It's still an open question whether OID+version is better than unique-ID for naming files that belong to different versions of the same relation. I can see arguments on both sides. regards, tom lane From Inoue@tpf.co.jp Tue Jun 27 19:13:30 2000 Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA12791 for ; Tue, 27 Jun 2000 19:13:28 -0400 (EDT) Received: from tpf.co.jp ([126.0.1.56] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with ESMTP id IAA01830; Wed, 28 Jun 2000 08:13:26 +0900 Message-ID: <395935CB.2CC10452@tpf.co.jp> Date: Wed, 28 Jun 2000 08:16:27 +0900 From: Hiroshi Inoue X-Mailer: Mozilla 4.73 [ja] (Windows NT 5.0; U) X-Accept-Language: ja MIME-Version: 1.0 To: Tom Lane CC: Bruce Momjian , "Mikheev, Vadim" , "'Peter Eisentraut'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <200006272123.RAA09720@candle.pha.pa.us> <13018.962141417@sss.pgh.pa.us> Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Status: RO Tom Lane wrote: > Bruce Momjian writes: > > Yes, good point about pg_shadow. They don't have databases. How do we > > get multiple pg_class tables in the same directory? Is the > > pg_class.relversion file a number like 1,2,3,4, or does it come out of > > some global counter like oid. If so, we could put them in the same > > directory. > > I think we could get away with insisting that each database store its > pg_class and friends in a separate tablespace (physically distinct > directory) from any other database. That gets around the OID conflict. > > It's still an open question whether OID+version is better than > unique-ID for naming files that belong to different versions of the > same relation. I can see arguments on both sides. > I don't stick to unique-ID. My main point has always been the transactional control of file allocation change. However *VERSION(_ID)* may be misleading because it couldn't mean the version of pg_class tuples. Regards. Hiroshi Inoue Inoue@tpf.co.jp From tgl@sss.pgh.pa.us Wed Jun 28 12:10:59 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA11316 for ; Wed, 28 Jun 2000 12:10:58 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA15790; Wed, 28 Jun 2000 12:11:40 -0400 (EDT) To: Bruce Momjian cc: "Mikheev, Vadim" , "'Peter Eisentraut'" , "'Hiroshi Inoue'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: <200006281425.KAA05633@candle.pha.pa.us> References: <200006281425.KAA05633@candle.pha.pa.us> Comments: In-reply-to Bruce Momjian message dated "Wed, 28 Jun 2000 10:25:21 -0400" Date: Wed, 28 Jun 2000 12:11:40 -0400 Message-ID: <15787.962208700@sss.pgh.pa.us> From: Tom Lane Status: ROr Bruce Momjian writes: > If we put multiple database tables in the same directory, have we > considered how to drop databases? Right now we do rm -rf: rm -rf will no longer work in a tablespaces environment anyway. (Even if you kept symlinks underneath the DB directory, rm -rf wouldn't follow them.) DROP DATABASE will have to be implemented honestly: run through pg_class and do a regular DROP on each user table. Once you've got rid of the user tables, rm -rf should suffice to get rid of the "home tablespace" as I've been calling it, with all the system tables therein. Now that you mention it, this is another reason why system tables for each database have to live in a separate tablespace directory: there's no other good way to do that final stage of DROP DATABASE. The DROP-each-table approach doesn't work for system tables (somewhere along about the point where you drop pg_attribute, DROP TABLE itself would stop working ;-)). However I do see a bit of a problem here: since DROP DATABASE is ordinarily executed by a backend that's running in a different database, how's it going to read pg_class of the target database? Perhaps it will be necessary to fire up a sub-backend that runs in the target DB for long enough to kill all the user tables. Looking messy... regards, tom lane From pgsql-hackers-owner+M3998@hub.org Wed Jun 28 19:53:28 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA27612 for ; Wed, 28 Jun 2000 19:53:27 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5SNqG142069; Wed, 28 Jun 2000 19:52:17 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5SNp7137729 for ; Wed, 28 Jun 2000 19:51:07 -0400 (EDT) Received: from tpf.co.jp ([126.0.1.56] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with ESMTP id IAA03041; Thu, 29 Jun 2000 08:50:01 +0900 Message-ID: <395A8FDF.1132EC6D@tpf.co.jp> Date: Thu, 29 Jun 2000 08:53:03 +0900 From: Hiroshi Inoue X-Mailer: Mozilla 4.73 [ja] (Windows NT 5.0; U) X-Accept-Language: ja MIME-Version: 1.0 To: Tom Lane CC: Bruce Momjian , "Mikheev, Vadim" , "'Peter Eisentraut'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items References: <16404.962213972@sss.pgh.pa.us> Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Tom Lane wrote: > "Hiroshi Inoue" writes: > > Why do we have to have system tables per *database* ? > > Is there anything wrong with global system tables ? > > And how about adding dbid to pg_class,pg_proc etc ? > > We could, but I think I'd vote against it on two grounds: > > 1. Reliability. If something corrupts pg_class, do you want to > lose your whole installation, or just one database? > > 2. Increased locking overhead/loss of concurrency. Currently, there > is very little lock contention between backends running in different > databases. A shared pg_class will be a single point of locking (as > well as a single point of failure) for the whole installation. Isn't current design of PG's *database* for dropdb using "rm -rf" rather than for above 1.2. ? If we couldn't rely on our db itself and our locking mechanism is poor,we could start different postmasters for different *database*s. > It would solve the DROP DATABASE problem kind of nicely, but really > it'd just be downgrading DROP DATABASE to a DROP SCHEMA operation... > What is our *DATABASE* ? Is it clear to all people ? At least it's a vague concept for me. Could you please tell me what kind of objects are our *DATABASE* objects but could not be schema objects ? Regards. Hiroshi Inoue From pgsql-hackers-owner+M4003@hub.org Thu Jun 29 10:41:19 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA28321 for ; Thu, 29 Jun 2000 10:39:57 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5T7nr158743; Thu, 29 Jun 2000 03:49:53 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by hub.org (8.10.1/8.10.1) with ESMTP id e5T7io146030 for ; Thu, 29 Jun 2000 03:44:51 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id JAA46266; Thu, 29 Jun 2000 09:43:20 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Thu, 29 Jun 2000 09:43:20 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA59A8@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Bruce Momjian'" Cc: "Mikheev, Vadim" , Hiroshi Inoue , Tom Lane , Thomas Lockhart , Peter Eisentraut , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: AW: [HACKERS] Big 7.1 open items Date: Thu, 29 Jun 2000 09:43:14 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="windows-1252" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > > ln -s data/base/testdb/myspace/extent1 /var/myspace/extent1/testdb > > The idea was to put the main files in the directory, and create Extent2, > Extent3 directories for the extents. The reasoning was, that the database subdir should be below the extentdir, so that creating different fs for each extent would be easier, and not depend on the database name. It is easy to create fs for: /var/myspace or /var/myspace[/extent1] /var/myspace/extent2 but not if it has dbname in it. Andreas From ZeugswetterA@wien.spardat.at Thu Jun 29 06:34:49 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id GAA25201 for ; Thu, 29 Jun 2000 06:34:44 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id GAA00379 for ; Thu, 29 Jun 2000 06:35:30 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id MAA33950; Thu, 29 Jun 2000 12:33:42 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Thu, 29 Jun 2000 12:33:42 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA59AC@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" Cc: "'Bruce Momjian'" , Peter Eisentraut , "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: AW: [HACKERS] Big 7.1 open items Date: Thu, 29 Jun 2000 12:33:39 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Status: RO > > > I think I would prefer the ability to place more than one > > database into > > > the same tablespace. > > > > You can put user tables from multiple databases into the same > > tablespace, under this proposal. Just not system tables. > > Yes, but then it is only half baked. Half baked or not, I think I am starting to like it. I think I would restrict such an automagically created tablespace (tblspace name = db name) to only contain tables from this database. Andreas From pgsql-hackers-owner+M4019@hub.org Thu Jun 29 13:24:36 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA08070 for ; Thu, 29 Jun 2000 13:24:35 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5THLf102550; Thu, 29 Jun 2000 13:21:41 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by hub.org (8.10.1/8.10.1) with ESMTP id e5THL1197262 for ; Thu, 29 Jun 2000 13:21:01 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:50625 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Thu, 29 Jun 2000 19:20:28 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 137i5r-0000BK-00; Thu, 29 Jun 2000 19:27:15 +0200 Date: Thu, 29 Jun 2000 19:27:15 +0200 (CEST) From: Peter Eisentraut To: Hiroshi Inoue cc: Zeugswetter Andreas SB , "'Mikheev, Vadim'" , PostgreSQL-development Subject: Re: AW: [HACKERS] Big 7.1 open items In-Reply-To: <3959D7CF.E447565@tpf.co.jp> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Hiroshi Inoue writes: > According to your another posting,your *database* hierarchy is > instance -> database -> schema -> object > like Oracle. > > However SQL92 seems to have another hierarchy: > cluster -> catalog -> schema -> object > and dot notation catalog.schema.object could be used. FYI: An "instance" is a "cluster". I don't know where the word instance came from, the docs sometimes call it "installation" or "site", which is even worse. I have been using "database cluster" for the latest documentation work. My dictionary defines a cluster as "a group of things gathered or occurring closely together", which is what this is. Call it a "data area" or an "initdb'ed thing", etc. A "catalog" can be equated with our "database". The method of creating catalogs is implementation defined, so our CREATE DATABASE command is in perfect compliance with the standard. We don't support the catalog.schema.object notation but that notation only makes sense when you can access more than one catalog at a time. We don't allow that and SQL doesn't require it. We could allow that notation and throw an error when the catalog name doesn't match the current database, but that's mere cosmetic work. In entry level SQL 92, a "schema" is essentially the same as table ownership. You can execute the command CREATE SCHEMA AUTHORIZATION "peter", which means that user "peter" (where he came from is "implementation-defined") can now create tables under his name. There is no such thing as a table owner, there's the "containing schema" and its owner. The tables "peter" creates can then be referenced by the dotted notation. But it is not correct to equate this with CREATE USER. Even if there was no schema for "peter" he could still connect and query other people's tables. Moving beyond SQL 92 you can also create schemas with a different name than your user name. This is merely a little more naming flexibility. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From peter@localhost.its.uu.se Thu Jun 29 19:25:40 2000 Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id TAA00202 for ; Thu, 29 Jun 2000 19:25:39 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:52854 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Fri, 30 Jun 2000 01:25:27 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 137nnA-00023q-00; Fri, 30 Jun 2000 01:32:20 +0200 Date: Fri, 30 Jun 2000 01:32:20 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <17726.962240702@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: Peter Eisentraut Status: RO Tom Lane writes: > You can put *user* tables from more than one database into a table space. > The restriction is just on *system* tables. I think my understanding as a user would be that a table space represents a storage location. If I want to put a table/object/entire database on a fancy disk somewhere I create a table space for it there. But if I want to store all my stuff under /usr/local/pgsql/data then I wouldn't expect to have to create more than one table space. So the table spaces become at that point affected by the logical hierarchy: I must make sure to have enough table spaces to have many databases. More specifically, what would the user interface to this look like? Clearly there has to be some sort of CREATE TABLESPACE command. Now does CREATE DATABASE imply a CREATE TABLESPACE? I think not. Do you have to create a table space before creating each database? I think not. > We could avoid it along the lines you suggest (name table files like > DBOID.RELOID.VERSION instead of just RELOID.VERSION) but is it really > worth it? I only intended that for pg_class and other bootstrap-sort-of tables, maybe all system tables. Normal heap files could look like RELOID.VERSION, whereas system tables would look like "name.DBOID". Clearly there's no market for renaming system tables or dropping any of their columns. We're obviously going to have to treat pg_class special anyway. > Vadim's concerned about every byte that has to go into the WAL log, > and I think he's got a good point. True. But if you only do it for the system tables then it might take less space than keeping track of lots of table spaces that are unneeded. :-) -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From pgsql-hackers-owner+M4032@hub.org Thu Jun 29 20:12:39 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA00852 for ; Thu, 29 Jun 2000 20:12:38 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5TNwm184774; Thu, 29 Jun 2000 19:58:48 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5TNvD180670 for ; Thu, 29 Jun 2000 19:57:14 -0400 (EDT) Received: from tpf.co.jp ([126.0.1.56] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with ESMTP id IAA04081; Fri, 30 Jun 2000 08:56:46 +0900 Message-ID: <395BE2F5.687E90B0@tpf.co.jp> Date: Fri, 30 Jun 2000 08:59:49 +0900 From: Hiroshi Inoue X-Mailer: Mozilla 4.73 [ja] (Windows NT 5.0; U) X-Accept-Language: ja MIME-Version: 1.0 To: Peter Eisentraut CC: Zeugswetter Andreas SB , "'Mikheev, Vadim'" , PostgreSQL-development Subject: Re: AW: [HACKERS] Big 7.1 open items References: Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Peter Eisentraut wrote: > Hiroshi Inoue writes: > > > According to your another posting,your *database* hierarchy is > > instance -> database -> schema -> object > > like Oracle. > > > > However SQL92 seems to have another hierarchy: > > cluster -> catalog -> schema -> object > > and dot notation catalog.schema.object could be used. > > FYI: Thanks. I'm asking to all what our *DATABASE* is. Different from you,I couldn't see any decisive feature in our *DATABASE*. > > > An "instance" is a "cluster". I don't know where the word instance came I could find the word in Oracle. IMHO,it corresponds to our initdb'ed thing(a postmaster controls). > > from, the docs sometimes call it "installation" or "site", which is even > worse. I have been using "database cluster" for the latest documentation > work. My dictionary defines a cluster as "a group of things gathered or > occurring closely together", which is what this is. Call it a "data area" > or an "initdb'ed thing", etc. > SQL92 seems to say that a cluster corresponds to a target of connection and has no name(after connection was established). Isn't it same as our *DATABASE* ? > > A "catalog" can be equated with our "database". The method of creating > catalogs is implementation defined, so our CREATE DATABASE command is in > perfect compliance with the standard. We don't support the > catalog.schema.object notation but that notation only makes sense when you > can access more than one catalog at a time. Yes,it's most essential that we couldn't access more than one catalog. This means that we have only one (noname) "catalog" per "cluster". > We don't allow that and SQL > doesn't require it. We could allow that notation and throw an error when > the catalog name doesn't match the current database, but that's mere > cosmetic work. > > In entry level SQL 92, a "schema" is essentially the same as table > ownership. You can execute the command CREATE SCHEMA AUTHORIZATION > "peter", which means that user "peter" (where he came from is > "implementation-defined") can now create tables under his name. There is > no such thing as a table owner, there's the "containing schema" and its > owner. The tables "peter" creates can then be referenced by the dotted > notation. But it is not correct to equate this with CREATE USER. Even if > there was no schema for "peter" he could still connect and query other > people's tables. > I've used *username* "schema"s in Oracle for a long time but I've never thought that it's the essence of "schema". If I recoginze correctly,the concept of "catalog" hasn't necessarily been important while "schema" = "user". The conflict of "schema" name is equivalent to the conflict of "user" name if "schema" = "user". IMHO,SQL92 has required the concept of "catalog" because "schema" has been changed to be independent of "user". Anyway in current PG "cluster":"catalog":"schema"=1:1:1(0) and our *DATABASE* is an only confusing concept in the hierarchy.. Regards, Hiroshi Inoue From tgl@sss.pgh.pa.us Thu Jun 29 20:42:56 2000 Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA00958 for ; Thu, 29 Jun 2000 20:42:55 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id UAA02520; Thu, 29 Jun 2000 20:43:32 -0400 (EDT) To: Peter Eisentraut cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: References: Comments: In-reply-to Peter Eisentraut message dated "Fri, 30 Jun 2000 01:32:20 +0200" Date: Thu, 29 Jun 2000 20:43:32 -0400 Message-ID: <2517.962325812@sss.pgh.pa.us> From: Tom Lane Status: RO Peter Eisentraut writes: > Tom Lane writes: >> You can put *user* tables from more than one database into a table space. >> The restriction is just on *system* tables. > More specifically, what would the user interface to this look like? > Clearly there has to be some sort of CREATE TABLESPACE command. Now does > CREATE DATABASE imply a CREATE TABLESPACE? I think not. Do you have to > create a table space before creating each database? I think not. I would say that CREATE DATABASE just implicitly creates a new tablespace that's physically located right under the toplevel data directory of the installation, no symlink. What's wrong with that? You need not keep anything except the system tables of the DB there if you don't want to. In practice, for someone who doesn't need to worry about tablespaces (because they put the installation on a disk with enough room for their purposes), the whole thing acts exactly the same as it does now. >> We could avoid it along the lines you suggest (name table files like >> DBOID.RELOID.VERSION instead of just RELOID.VERSION) but is it really >> worth it? > I only intended that for pg_class and other bootstrap-sort-of tables, > maybe all system tables. Normal heap files could look like RELOID.VERSION, > whereas system tables would look like "name.DBOID". That would imply that the very bottom levels of the system know all about which tables are system tables and which are not (and, if you are really going to insist on the "name" part of that, that they know what name goes with each system-table OID). I'd prefer to avoid that. The less the smgr knows about the upper levels of the system, the better. > Clearly there's no market for renaming system tables or dropping any > of their columns. No, but there is a market for compacting indexes on system relations, and I haven't heard a good proposal for doing index compaction in place. So we need versioning for system indexes. >> Vadim's concerned about every byte that has to go into the WAL log, >> and I think he's got a good point. > True. But if you only do it for the system tables then it might take less > space than keeping track of lots of table spaces that are unneeded. :-) Again, WAL should not need to distinguish system and user tables. And as for the keeping track, the tablespace OID will simply replace the database OID in the log and in the smgr interfaces. There's no "extra" cost, except maybe by comparison to a system with neither tablespaces nor multiple databases. regards, tom lane From peter@localhost.its.uu.se Sat Jul 1 10:39:11 2000 Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA02996 for ; Sat, 1 Jul 2000 10:39:10 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:50862 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Sat, 1 Jul 2000 16:56:49 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 138Oo3-0003UQ-00; Sat, 01 Jul 2000 17:03:43 +0200 Date: Sat, 1 Jul 2000 17:03:42 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <2517.962325812@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: Peter Eisentraut Status: RO Tom Lane writes: > In practice, for someone who doesn't need to worry about tablespaces > (because they put the installation on a disk with enough room for > their purposes), the whole thing acts exactly the same as it does now. But I'd venture the guess that for someone who wants to use tablespaces it wouldn't work as expected. Table spaces should represent a physical storage location. Creation of table spaces should be a restricted operation, possibly more than, but at least differently from, databases. Eventually, table spaces probably will have attributes, such as optimization parameters (random_page_cost). This will not work as expected if you intermix them with the databases. I'd expect that if I have three disks and 50 databases, then I make three tablespaces and assign the databases to them. I'll bet lunch that if we don't do it that way that before long people will come along and ask for something that does work this way. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From pgsql-hackers-owner+M4066@hub.org Sat Jul 1 13:21:39 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id NAA03777 for ; Sat, 1 Jul 2000 13:21:38 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e61He8S63312; Sat, 1 Jul 2000 13:40:08 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e61Hd7S58820 for ; Sat, 1 Jul 2000 13:39:07 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id NAA22822; Sat, 1 Jul 2000 13:37:21 -0400 (EDT) To: Peter Eisentraut cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-reply-to: References: Comments: In-reply-to Peter Eisentraut message dated "Sat, 01 Jul 2000 17:03:42 +0200" Date: Sat, 01 Jul 2000 13:37:21 -0400 Message-ID: <22819.962473041@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Peter Eisentraut writes: > I'd expect that if I have three disks and 50 databases, then I make three > tablespaces and assign the databases to them. In our last installment, you were complaining that you didn't want to be bothered with that ;-) But I don't see any reason why CREATE DATABASE couldn't take optional parameters indicating where to create the new DB's default tablespace. We already have a LOCATION option for it that does something close to that. Come to think of it, it would probably make sense to adapt the existing notion of "location" (cf initlocation script) into something meaning "directory that users are allowed to create tablespaces (including databases) in". If there were an explicit table of allowed locations, it could be used to address the protection issues you raise --- for example, a location could be restricted so that only some users could create tablespaces/databases in it. $PGDATA/data would be just the first location in every installation. regards, tom lane From pgsql-hackers-owner+M4078@hub.org Sun Jul 2 11:16:52 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id LAA14294 for ; Sun, 2 Jul 2000 11:16:51 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e62FGqS51200; Sun, 2 Jul 2000 11:16:52 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by hub.org (8.10.1/8.10.1) with ESMTP id e62FGaS50925 for ; Sun, 2 Jul 2000 11:16:36 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:52424 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Sun, 2 Jul 2000 17:15:57 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 138lZz-0001VD-00; Sun, 02 Jul 2000 17:22:43 +0200 Date: Sun, 2 Jul 2000 17:22:43 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: "Mikheev, Vadim" , "'Hiroshi Inoue'" , Thomas Lockhart , Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: Re: [HACKERS] Big 7.1 open items In-Reply-To: <22819.962473041@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Tom Lane writes: > Come to think of it, it would probably make sense to adapt the existing > notion of "location" (cf initlocation script) into something meaning > "directory that users are allowed to create tablespaces (including > databases) in". This is what I've been trying to push all along. But note that this mechanism does allow multiple databases per location. :) -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From ZeugswetterA@wien.spardat.at Mon Jul 3 04:30:07 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id EAA16088 for ; Mon, 3 Jul 2000 04:30:05 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id EAA19031 for ; Mon, 3 Jul 2000 04:30:07 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id KAA28416; Mon, 3 Jul 2000 10:28:06 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 3 Jul 2000 10:28:06 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA59B0@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Hiroshi Inoue'" , Peter Eisentraut , Tom Lane Cc: Bruce Momjian , Jan Wieck , PostgreSQL-development , "Ross J. Reedstrom" Subject: AW: [HACKERS] Big 7.1 open items Date: Mon, 3 Jul 2000 10:28:05 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="windows-1252" Status: RO > > > > > In my mind the point of the "database" concept is to > > > provide a domain > > > > > within which custom datatypes and functions are available. > > > > > > > > > > AFAIK few users understand it and many users have wondered > > > why we couldn't issue cross "database" queries. > > > > Imho the same issue is access to tables on another machine. > > If we "fix" that, access to another db on the same instance is just > > a variant of the above. > > > > What is a difference between SCHAMA and your "database" ? > I myself am confused about them. "my *database*" corresponds to the current database, which is created with "create database" in postgresql. It corresponds to the catalog concept in SQL99. The schema is below the database. Access to different schemas with one connection is mandatory. Access to different catalogs (databases) with one connection is not mandatory, but should imho be solved analogous to access to another catalog on a different (SQL99) cluster. This would be a very nifty feature. Andreas From pgsql-hackers-owner+M3496@hub.org Fri Jun 16 15:55:14 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id OAA02116 for ; Fri, 16 Jun 2000 14:55:13 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id NAA21581 for ; Fri, 16 Jun 2000 13:53:58 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5GHpqN06086; Fri, 16 Jun 2000 13:51:52 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5GHpcN05946 for ; Fri, 16 Jun 2000 13:51:39 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id NAA07945 for ; Fri, 16 Jun 2000 13:51:38 -0400 (EDT) To: pgsql-hackers@postgresql.org Subject: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename Date: Fri, 16 Jun 2000 13:51:37 -0400 Message-ID: <7942.961177897@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO After further thought I think there's a lot of merit in Hiroshi's opinion that physical file names should not be tied to relation OID. If we use a separately generated value for the file name, we can solve a lot of problems pretty nicely by means of "table versioning". For example: VACUUM can't compact indexes at the moment, and what it does do (scan the index and delete unused entries) is really slow. The right thing to do is for it to generate an all-new index file, but how do we do that without creating a risk of leaving the index corrupted if we crash partway through? The answer is to build the new index in a new physical file. But how do we install the new file as the real index atomically, when it might span multiple segments? If the physical file name is decoupled from the relation's name *and* OID then there is no problem: the atomic event that makes the new file(s) the real table contents is the commit of the new pg_class row with the new value for the physical filename. Aside from possible improvements in VACUUM, this would let us do a robust implementation of CLUSTER, and we could do the "really change the table" variant of ALTER TABLE DROP COLUMN the same way if anyone wants to do it. The only cost is that we need an additional column in pg_class to hold the physical file name. That's not so bad, especially when you remember that we'd surely need to add something to pg_class for tablespace support anyway. If we bite that bullet, then we could also do something to satisfy Bruce about having legible file names ;-). The column in pg_class could perfectly well be a string, not a pure number, and that means that we can throw in the relname (truncated to fit of course). So the thing would act a lot like the original-relname-plus-OID variant that's been discussed so far. (Original relname because ALTER TABLE RENAME would *not* change the physical file name. But we could think about a form of VACUUM that creates a whole new table by versioning, and that would presumably bring the physical name back in sync with the logical relname.) Here is a sketch of a concrete proposal. I see no need to have separate pg_class columns for tablespace and physical relname; instead, I suggest there be a column of type NAME that is the file pathname (relative to the database directory). Further, instead of the existing convention of appending .N to the base file name to make extension segment names, I propose that we always have a segment number in the physical file name, and that the pg_class entry be required to contain a "%d" somewhere that indicates where. The actual filename is manufactured by sprintf(tempbuf, value_from_pg_class_column, segment_number); As an example, the arrangement I was suggesting earlier today about segments in different subdirectories of a tablespace could be implemented by assigning physical filenames like tablespace/%d/12345_relname where the 12345 is a value generated separately from the table's OID. (We would still use the OID counter to produce these numbers, and in fact there's no reason not to use the table's OID as the initial unique ID for the physical filename. The point is just that the physical filename doesn't have to remain forever equal to the relation's OID.) If we use type NAME for this string then the tablespace part of the path would have to be kept to no more than ~ 15 characters, but that seems workable enough. (Anybody who really didn't like that could recompile with larger NAMEDATALEN. Doesn't seem worth inventing a separate type.) As Hiroshi pointed out, one of the best aspects of this approach is that the physical table layout policy doesn't have to be hard-wired into low-level file access routines. The low-level routines don't need to know much of anything about the format of the pathname, they just stuff in the right segment number and use the name. The layout policy need only be known to one single routine that generates the strings that go into pg_class. So it'd be really easy to change. One thing we'd have to work out is that the critical system tables (eg, pg_class itself, as well as its indexes) would have to have predictable physical names. Otherwise there's no way for a new backend to bootstrap itself up ... it can't very well read pg_class to find out where pg_class is. A brute-force solution is to forbid reversioning of the critical tables, but I suspect we can find a less restrictive answer. This seems like it'd satisfy all the concerns that have been raised. Comments? regards, tom lane From pgsql-hackers-owner+M3524@hub.org Fri Jun 16 22:30:59 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA07796 for ; Fri, 16 Jun 2000 21:30:58 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id VAA26393 for ; Fri, 16 Jun 2000 21:16:37 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5H1EeM94683; Fri, 16 Jun 2000 21:14:40 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5H1D0M94365 for ; Fri, 16 Jun 2000 21:13:00 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id VAA10209; Fri, 16 Jun 2000 21:12:30 -0400 (EDT) To: Chris Bitmead cc: pgsql-hackers@postgreSQL.org Subject: Re: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename In-reply-to: <394ACB42.C87C59B8@bitmead.com> References: <7942.961177897@sss.pgh.pa.us> <394ACB42.C87C59B8@bitmead.com> Comments: In-reply-to Chris Bitmead message dated "Sat, 17 Jun 2000 10:50:10 +1000" Date: Fri, 16 Jun 2000 21:12:29 -0400 Message-ID: <10206.961204349@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Chris Bitmead writes: > At least on UNIX, couldn't you use a hard-link and change the name in > pg_class immediately? Let the brain-dead operating systems use the > vacuum method. Hmm ... maybe, but it doesn't seem worth the portability headache to me. We do have an NT port that we don't want to break, and I don't think RENAME TABLE is worth the trouble of testing/supporting two implementations. Even on Unix, aren't there filesystems that don't do hard links? Not that I'd recommend running Postgres on such a volume, but... regards, tom lane From pgsql-hackers-owner+M3525@hub.org Sat Jun 17 07:01:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id GAA22194 for ; Sat, 17 Jun 2000 06:01:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id FAA21836 for ; Sat, 17 Jun 2000 05:39:21 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5H9bSM88777; Sat, 17 Jun 2000 05:37:28 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5H9anM88603 for ; Sat, 17 Jun 2000 05:36:49 -0400 (EDT) Received: from mcadnote1 (ppm130.noc.fukui.nsk.ne.jp [210.161.188.49]) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id SAA08384; Sat, 17 Jun 2000 18:36:00 +0900 From: "Hiroshi Inoue" To: "Tom Lane" Cc: Subject: RE: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename Date: Sat, 17 Jun 2000 18:38:53 +0900 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) In-Reply-To: <7942.961177897@sss.pgh.pa.us> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.6700 Importance: Normal X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: pgsql-hackers-owner@hub.org [mailto:pgsql-hackers-owner@hub.org]On > Behalf Of Tom Lane > > After further thought I think there's a lot of merit in Hiroshi's > opinion that physical file names should not be tied to relation OID. > If we use a separately generated value for the file name, we can > solve a lot of problems pretty nicely by means of "table versioning". > > For example: VACUUM can't compact indexes at the moment, and what it > does do (scan the index and delete unused entries) is really slow. > The right thing to do is for it to generate an all-new index file, > but how do we do that without creating a risk of leaving the index > corrupted if we crash partway through? The answer is to build the > new index in a new physical file. But how do we install the new > file as the real index atomically, when it might span multiple > segments? If the physical file name is decoupled from the relation's > name *and* OID then there is no problem: the atomic event that makes > the new file(s) the real table contents is the commit of the new > pg_class row with the new value for the physical filename. > > Aside from possible improvements in VACUUM, this would let us do a > robust implementation of CLUSTER, and we could do the "really change > the table" variant of ALTER TABLE DROP COLUMN the same way if anyone > wants to do it. > Yes,I've wondered how do we implement column_is_really_dropped ALTER TABLE DROP COLUMN feature without this kind of mechanism. > The only cost is that we need an additional column in pg_class to > hold the physical file name. That's not so bad, especially when > you remember that we'd surely need to add something to pg_class for > tablespace support anyway. > > If we bite that bullet, then we could also do something to satisfy > Bruce about having legible file names ;-). The column in pg_class > could perfectly well be a string, not a pure number, and that means > that we can throw in the relname (truncated to fit of course). So > the thing would act a lot like the original-relname-plus-OID variant > that's been discussed so far. (Original relname because ALTER TABLE > RENAME would *not* change the physical file name. But we could > think about a form of VACUUM that creates a whole new table by > versioning, and that would presumably bring the physical name back > in sync with the logical relname.) > > As Hiroshi pointed out, one of the best aspects of this approach > is that the physical table layout policy doesn't have to be hard-wired > into low-level file access routines. The low-level routines don't > need to know much of anything about the format of the pathname, > they just stuff in the right segment number and use the name. The > layout policy need only be known to one single routine that generates > the strings that go into pg_class. So it'd be really easy to change. > Ross's approach is fundamentally same though he is using relname+OID naming rule. I've said his trial is most practical one. > One thing we'd have to work out is that the critical system tables > (eg, pg_class itself, as well as its indexes) would have to have > predictable physical names. The only limitation of the relation filename is the uniqueness. So it doesn't introduce any inconsistency that system tables have fixed name. As for system relations it wouldn't be so bad because CLUSTER/ ALTER TABLE DROP COLUMN ... would be unnecessary(maybe). But as for system indexes,it is preferable that VACUUM/REINDEX could rebuild them safely. System indexes never shrink currently. Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3529@hub.org Sat Jun 17 10:01:24 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id JAA24004 for ; Sat, 17 Jun 2000 09:01:23 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id IAA28633 for ; Sat, 17 Jun 2000 08:57:47 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5HCtxM77095; Sat, 17 Jun 2000 08:55:59 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by hub.org (8.10.1/8.10.1) with ESMTP id e5HCtoM77026 for ; Sat, 17 Jun 2000 08:55:50 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:57716 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Sat, 17 Jun 2000 14:55:25 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 133IET-0002Y3-00; Sat, 17 Jun 2000 15:01:53 +0200 Date: Sat, 17 Jun 2000 15:01:53 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: pgsql-hackers@postgreSQL.org Subject: Re: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename In-Reply-To: <7942.961177897@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Tom Lane writes: > tablespace/%d/12345_relname Throwing table spaces and relation names into one pot doesn't excite me very much. For example, before long people will want to * Query what tables are in what space (without using string operations) Consider for example creating a new table and choosing where to put it. * Rename table spaces * Assign attributes of some sort to table spaces (permissions, etc.) * Use table space names with more than 15 characters. :) Somehow table spaces need to be catalogued. You could still make the physical file name 'tablespaceoid/rest' without actually having to look up anything, although that depends on your symlink idea which is still under discussion. Then, why are all nth segments of tables in one directory in that proposal? Also, you said before that an old relname (after rename) is worse than none at all. I couldn't agree more. Why not use OID.[SEGMENT.]VERSION for the physical relname (different order possible)? That way you at least have some guaranteed correspondence between files and tables. Version could probably be an INT2, so you save some space. -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From pgsql-hackers-owner+M3534@hub.org Sat Jun 17 13:31:11 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id MAA02801 for ; Sat, 17 Jun 2000 12:31:10 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id MAA07848 for ; Sat, 17 Jun 2000 12:27:14 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5HGPJM95074; Sat, 17 Jun 2000 12:25:19 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (sss.pgh.pa.us [209.114.166.2]) by hub.org (8.10.1/8.10.1) with ESMTP id e5HGP1M94990 for ; Sat, 17 Jun 2000 12:25:01 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss2.sss.pgh.pa.us (8.9.3/8.9.3) with ESMTP id MAA18939; Sat, 17 Jun 2000 12:24:56 -0400 (EDT) To: "Hiroshi Inoue" cc: pgsql-hackers@postgreSQL.org Subject: Re: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename In-reply-to: References: Comments: In-reply-to "Hiroshi Inoue" message dated "Sat, 17 Jun 2000 18:38:53 +0900" Date: Sat, 17 Jun 2000 12:24:56 -0400 Message-ID: <18936.961259096@sss.pgh.pa.us> From: Tom Lane X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO "Hiroshi Inoue" writes: >> One thing we'd have to work out is that the critical system tables >> (eg, pg_class itself, as well as its indexes) would have to have >> predictable physical names. > The only limitation of the relation filename is the uniqueness. > So it doesn't introduce any inconsistency that system tables > have fixed name. > As for system relations it wouldn't be so bad because CLUSTER/ > ALTER TABLE DROP COLUMN ... would be unnecessary(maybe). > But as for system indexes,it is preferable that VACUUM/REINDEX > could rebuild them safely. System indexes never shrink currently. Right, it's the index-shrinking business that has me worried. Most of the other reasons for swapping in a new file don't apply to system tables, but that one does. One possibility is to say that system *tables* can't be reversioned (at least not the critical ones) but system *indexes* can be. Then we'd have to use your ignore-system-indexes stuff during backend startup, until we'd found out where the indexes are. Might be too big a time penalty however... not sure. Shared cache inval of a system index could be a little tricky too; I don't think the catcache routines are prepared to fall back to non-index scan are they? On the whole it might be better to cheat by using a side data structure like the pg_internal.init file, that a backend could consult to find out where the indexes are now. regards, tom lane From pgsql-hackers-owner+M3553@hub.org Sun Jun 18 18:31:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id RAA08740 for ; Sun, 18 Jun 2000 17:31:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id RAA18332 for ; Sun, 18 Jun 2000 17:21:51 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5ILJcM11720; Sun, 18 Jun 2000 17:19:38 -0400 (EDT) Received: from merganser.its.uu.se (merganser.its.uu.se [130.238.6.236]) by hub.org (8.10.1/8.10.1) with ESMTP id e5ILILM09628 for ; Sun, 18 Jun 2000 17:18:21 -0400 (EDT) Received: from regulus.student.UU.SE ([130.238.5.2]:40239 "EHLO regulus.its.uu.se") by merganser.its.uu.se with ESMTP id ; Sun, 18 Jun 2000 23:17:49 +0200 Received: from peter (helo=localhost) by regulus.its.uu.se with local-esmtp (Exim 3.02 #2) id 133mYM-0000Ns-00; Sun, 18 Jun 2000 23:24:26 +0200 Date: Sun, 18 Jun 2000 23:24:26 +0200 (CEST) From: Peter Eisentraut To: Tom Lane cc: PostgreSQL Development Subject: Re: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename In-Reply-To: <19045.961260445@sss.pgh.pa.us> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO Tom Lane writes: > I don't think it's a good idea to have to consult pg_tablespace to find > out where a table actually is --- I think the pathname (or smgr access > token as Ross would call it ;-)) ought to be determinable from just the > pg_class entry. That's why I suggested the table space oid. That would be readily available from pg_class. > Tablespaces can have logical names stored in pg_tablespace; they just > can't contribute more than a dozen or so characters to file pathnames > under the implementation I'm proposing. That doesn't seem too > unreasonable; the pathname part can be some sort of abbreviated name. Since the abbreviated name is really only used internally it might as well be the oid. Otherwise you create a weird functional dependency like the pg_shadow.usesysid field that's just an extra layer of maintenance. > this implementation mechanism will support either policy choice --- > original relname in the filename, or just a numeric ID for the > filename But when you look at a file name `12345_accounts_recei' you know neither * whether the table name was really `accounts_recei' or whether the name was truncated * whether the table still has that name, whatever it was * what table this is at all So in the aggregate you really know less than nothing. :-) > > Why not use OID.[SEGMENT.]VERSION for the physical relname (different > > order possible)? > > Doesn't give you a manageable way to split segments across different > disks. Okay, so maybe ${base}/TABLESPACEOID/SEGMENT/RELOID.VERSION. This doesn't need any catalog lookup outside of pg_class, yet it's still easy to resolve to human-readable names by simple admin tools (SELECT * FROM pg_foo WHERE oid = xxx). VERSION would be unique within a conceptual relation, so you could even see how many times the relation was altered in major ways (kind of). -- Peter Eisentraut Sernanders väg 10:115 peter_e@gmx.net 75262 Uppsala http://yi.org/peter-e/ Sweden From pgsql-hackers-owner+M3561@hub.org Sun Jun 18 21:31:03 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id UAA20523 for ; Sun, 18 Jun 2000 20:31:02 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id UAA25719 for ; Sun, 18 Jun 2000 20:26:49 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5J0OLM53050; Sun, 18 Jun 2000 20:24:21 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5J0NmM50883 for ; Sun, 18 Jun 2000 20:23:49 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id JAA09003; Mon, 19 Jun 2000 09:22:45 +0900 From: "Hiroshi Inoue" To: "Chris Bitmead" , "Tom Lane" Cc: "Peter Eisentraut" , Subject: RE: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename Date: Mon, 19 Jun 2000 09:24:56 +0900 Message-ID: <000901bfd984$cbf1dfc0$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: <394C20C6.9580A8A9@bitmead.com> X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Importance: Normal X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: pgsql-hackers-owner@hub.org [mailto:pgsql-hackers-owner@hub.org]On > Behalf Of Chris Bitmead > > Tom Lane wrote: > > > > Also, you said before that an old relname (after rename) is worse than > > > none at all. I couldn't agree more. > > > > I'm not the one who wants relnames in the physical names ;-). However, > > this implementation mechanism will support either policy choice --- > > original relname in the filename, or just a numeric ID for the filename > > --- and that seems like a good sign to me. > > > > > Why not use OID.[SEGMENT.]VERSION for the physical relname (different > > > order possible)? > > Unless VERSION is globally unique like an oid is, having RELNAME.VERSION > would be a problem if you created a table with the same name as a > recently renamed table. > In my proposal(relname+unique-id),the unique-id is globally unique and relname is only for dba's convenience. I've said many times that we should be free from the rule of file naming as far as possible. I myself don't mind the name of relation files except that they should be globally unique. I had to propose my opinion for file naming because people have been so enthusiastic about globally_not_unique file naming. Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3523@hub.org Fri Jun 16 22:01:00 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id VAA07568 for ; Fri, 16 Jun 2000 21:00:59 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id UAA25354 for ; Fri, 16 Jun 2000 20:54:02 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5H0q3M53458; Fri, 16 Jun 2000 20:52:03 -0400 (EDT) Received: from tech.com.au (IDENT:root@techpt.lnk.telstra.net [139.130.75.122]) by hub.org (8.10.1/8.10.1) with ESMTP id e5H0oRM47761 for ; Fri, 16 Jun 2000 20:50:28 -0400 (EDT) Received: from bitmead.com (IDENT:chris@tardis [203.41.180.243]) by tech.com.au (8.9.3/8.9.3) with ESMTP id KAA21482; Sat, 17 Jun 2000 10:50:14 +1000 Message-ID: <394ACB42.C87C59B8@bitmead.com> Date: Sat, 17 Jun 2000 10:50:10 +1000 From: Chris Bitmead X-Mailer: Mozilla 4.72 [en] (X11; U; Linux 2.2.14-5.0 i686) X-Accept-Language: en MIME-Version: 1.0 To: Tom Lane CC: pgsql-hackers@postgreSQL.org Subject: Re: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename References: <7942.961177897@sss.pgh.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Tom Lane wrote: So > the thing would act a lot like the original-relname-plus-OID variant > that's been discussed so far. (Original relname because ALTER TABLE > RENAME would *not* change the physical file name. But we could > think about a form of VACUUM that creates a whole new table by > versioning, and that would presumably bring the physical name back > in sync with the logical relname.) At least on UNIX, couldn't you use a hard-link and change the name in pg_class immediately? Let the brain-dead operating systems use the vacuum method. From pgsql-hackers-owner+M3576@hub.org Mon Jun 19 01:58:35 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id AAA00789 for ; Mon, 19 Jun 2000 00:58:34 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5J4qfM87650; Mon, 19 Jun 2000 00:52:41 -0400 (EDT) Received: from sd.tpf.co.jp (sd.tpf.co.jp [210.161.239.34]) by hub.org (8.10.1/8.10.1) with ESMTP id e5J4oUM77400 for ; Mon, 19 Jun 2000 00:50:30 -0400 (EDT) Received: from cadzone ([126.0.1.40] (may be forged)) by sd.tpf.co.jp (2.5 Build 2640 (Berkeley 8.8.6)/8.8.4) with SMTP id NAA09265; Mon, 19 Jun 2000 13:50:22 +0900 From: "Hiroshi Inoue" To: "Peter Eisentraut" Cc: "PostgreSQL Development" , "Tom Lane" Subject: RE: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generatedfilename Date: Mon, 19 Jun 2000 13:52:34 +0900 Message-ID: <001201bfd9aa$2f1c1320$2801007e@tpf.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Importance: Normal X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > -----Original Message----- > From: pgsql-hackers-owner@hub.org [mailto:pgsql-hackers-owner@hub.org]On > Behalf Of Peter Eisentraut > > Tom Lane writes: > > > I don't think it's a good idea to have to consult pg_tablespace to find > > out where a table actually is --- I think the pathname (or smgr access > > token as Ross would call it ;-)) ought to be determinable from just the > > pg_class entry. > > That's why I suggested the table space oid. That would be readily > available from pg_class. > It seems to me that the following 1)2) has always been mixed up. IMHO,they should be distinguished clearly. 1) Where the table is stored Currently PostgreSQL relies on relname -> filename mapping rule to access *existent* relations and doesn't have this information in its database. Our(Tom,Ross,me) proposal is to keep the information(token) in pg_class and provide a standard transactional control mechanism for the change of table file allocation. By doing it we would be able to be free from table allocation(naming) rule. Isn't it a kind of thing why we haven't had it from the first ? 2) Where to store the table Yes,TABLE(DATA)SPACE should encapsulate this concept. I want the decision about 1) first. Ross has already tried it without 2). Comments ? As for 2) every one seems to have each opinion and the discussion has always been divergent. Please don't discard 1) together. Regards. Hiroshi Inoue Inoue@tpf.co.jp From pgsql-hackers-owner+M3591@hub.org Mon Jun 19 11:01:19 2000 Received: from renoir.op.net (root@renoir.op.net [207.29.195.4]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA21409 for ; Mon, 19 Jun 2000 10:01:18 -0400 (EDT) Received: from hub.org (root@hub.org [216.126.84.1]) by renoir.op.net (o1/$Revision: 1.8 $) with ESMTP id JAA05383 for ; Mon, 19 Jun 2000 09:56:59 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e5JDsVM91574; Mon, 19 Jun 2000 09:54:31 -0400 (EDT) Received: from gandalf.it-austria.net (gandalf.it-austria.net [213.150.1.65]) by hub.org (8.10.1/8.10.1) with ESMTP id e5JDldM77267 for ; Mon, 19 Jun 2000 09:48:05 -0400 (EDT) Received: from sdexcgtw01.f000.d0188.sd.spardat.at (sdgtw.sd.spardat.at [172.18.1.16]) by gandalf.it-austria.net (xxx/xxx) with ESMTP id PAA80686; Mon, 19 Jun 2000 15:46:24 +0200 Received: by sdexcgtw01.f000.d0188.sd.spardat.at with Internet Mail Service (5.5.2448.0) id ; Mon, 19 Jun 2000 15:46:24 +0200 Message-ID: <219F68D65015D011A8E000006F8590C605BA5978@sdexcsrv1.f000.d0188.sd.spardat.at> From: Zeugswetter Andreas SB To: "'Tom Lane'" , Peter Eisentraut Cc: pgsql-hackers@postgresql.org Subject: AW: [HACKERS] OK, OK, Hiroshi's right: use a seperately-generated filename Date: Mon, 19 Jun 2000 15:46:22 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: RO > It's better than *all* segments of tables in one directory, which is > what you get if the segment number is just a component of a flat file > name. We have to have a better answer than that for people who need > to cope with tables bigger than a disk. Perhaps someone can > think of a > better answer than subdirectory-per-segment-number, but I think that > will work well enough; and it doesn't add any complexity for file > access. I do not see this connection between a filesystem and a disk ? Modern systems have the ability to join more than one disk into one filesystem. Also if we think about separating large tables into smaller parts we imho want something where the optimizer has knowledge what data it finds in what part of the table. Andreas From pgsql-hackers-owner+M4680@hub.org Mon Jul 10 11:16:07 2000 Received: from hub.org (root@hub.org [216.126.84.1]) by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id KAA28153 for ; Mon, 10 Jul 2000 10:16:06 -0400 (EDT) Received: from hub.org (majordom@localhost [127.0.0.1]) by hub.org (8.10.1/8.10.1) with SMTP id e6AEG5W83419; Mon, 10 Jul 2000 10:16:05 -0400 (EDT) Received: from corvette.mascari.com (dhcp160176144.columbus.rr.com [24.160.176.144]) by hub.org (8.10.1/8.10.1) with ESMTP id e6AE7FW63372 for ; Mon, 10 Jul 2000 10:07:24 -0400 (EDT) Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id KAA10768; Mon, 10 Jul 2000 10:03:27 -0400 Message-ID: <3969D7CA.8AF9573C@mascari.com> Date: Mon, 10 Jul 2000 10:03:54 -0400 From: Mike Mascari Organization: Mascari Development Inc X-Mailer: Mozilla 4.72 [en] (X11; U; Linux 2.2.5-15 i586) X-Accept-Language: en MIME-Version: 1.0 To: Bruce Momjian CC: Tom Lane , Philip Warner , Chris Bitmead , "pgsql-hackers@postgreSQL.org" Subject: Re: [HACKERS] Re: [GENERAL] PostgreSQL vs. MySQL References: <200007101310.JAA26260@candle.pha.pa.us> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailing-List: pgsql-hackers@postgresql.org Precedence: bulk Sender: pgsql-hackers-owner@hub.org Status: ROr Bruce Momjian wrote: > > > And of course the major problem with *that* is how do you get the > > connection request to arrive at a backend that's been prestarted in > > the right database? If you don't commit to a database then there's > > not a whole lot of prestarting that can be done. > > > > It occurs to me that this'd get a whole lot more feasible if one > > postmaster == one database, which is something we *could* do if we > > implemented schemas. Hiroshi's been arguing that the current hard > > separation between databases in an installation should be done away > > with in favor of schemas, and I'm starting to see his point... > > This is interesting. You believe schema's would allow a pool of > backends to connect to any database? That would clearly be a win. I'm just curious, but did a consensus ever develop on schemas? It seemed that the schemas/tablespace thread just ran out of steam. For what its worth, I like the idea of: 1. PostgreSQL installation -> SQL cluster of catalogs 2. PostgreSQL database -> SQL catalog 3. PostgreSQL schema -> SQL schema This correlates nicely with the current representation of DATABASE. People can run multiple SQL clusters by running multiple postmasters on different ports. Today, most people achieve a logical separation of data by issuing multiple CREATE DATABASE commands. But under the above, most sites would run with a single PostgreSQL database (SQL catalog), since: "Catalogs are named collections of schemas in an SQL-environment" This would mirror the behavior of Oracle, where most people run with a single Oracle SID. The logical separation would be achieved with SCHEMA's a level under the current DATABASE (a.k.a. catalog). This eliminates the problem of using softlinks and creating various subdirectories to mirror *logical* parititioning of data. It also alleviates the problem people currently encounter when they've built their data model around multiple DATABASE's but learn later that they need access to more than one simultaneously. Instead, they'll model their design around multiple SCHEMA's which exist within a single DATABASE instance. It seems that the discussion of tablespaces shouldn't be mixed with SCHEMA's except to note that a DATABASE (catalog) should have a default TABLESPACE whose path matches the current one: ../pgsql/data/base/ Later, users might be able to create a hierarchy of default TABLESPACE's where the location of the object is found with logic like: 1. Is there a object-specified tablespace? (ex: CREATE TABLE payroll IN TABLESPACE...) 2. Is there a user-specified default tablespace? (ex: CREATE USER mike DEFAULT TABLESPACE...) 2. Is there a schema-specified default tablespace? (ex: CREATE SCHEMA accounting DEFAULT TABLESPACE..) 3. Use the catalog-default tablespace (ex: CREATE DATABASE postgres DEFAULT LOCATION '/home/pgsql') with the last example creating the system tablespace, 'system_tablespace', with '/home/pgsql' as the location. Anyways, it seems a consensus should be developed on the whole Cluster/Catalog/Schema scenario. Mike Mascari From Albert.Langer@Directory-Designs.org Sun Apr 15 12:57:07 2001 Received: from relay1.pair.com (relay1.pair.com [209.68.1.20]) by candle.pha.pa.us (8.9.0/8.9.0) with SMTP id MAA22644 for ; Sun, 15 Apr 2001 12:57:06 -0400 (EDT) Received: (qmail 16730 invoked from network); 15 Apr 2001 16:56:26 -0000 Received: from cpe-144-132-70-18.vic.bigpond.net.au (HELO w98) (144.132.70.18) by relay1.pair.com with SMTP; 15 Apr 2001 16:56:26 -0000 X-pair-Authenticated: 144.132.70.18 Reply-To: From: "Albert Langer" To: "'Bruce Momjian'" , "'Hiroshi Inoue'" , "'Ross J. Reedstrom'" , "'Mike Mascari'" , , "'Tom Lane'" , "'Zeugswetter Andreas SB'" , "'The Hermit Hacker'" , "'Oliver Elphick'" , "'Don Baccus'" , "'Thomas Lockhart'" , "'Chris Bitmead'" , "'Philip J. Warner'" , "'Peter Eisentraut'" , "'Lamar Owen'" , "'Vadim Mikheev'" Subject: Tablespaces - checkout SAP DB Date: Mon, 16 Apr 2001 02:56:04 +1000 Message-ID: <000001c0c5cc$f5fd6ac0$6628a8c0@nowhere.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook CWS, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Importance: Normal Status: RO Hi everyone, Sorry about the long To list - this is to everyone I noticed commenting in: http://www.postgresql.org/docs/pgsql/doc/TODO.detail/tablespaces I strongly recommend checkout of approach used in SAP DB: http://www.sap.com/solutions/technology/sapdb/sap_db_documentation.htm Their glossy 2 page brochure emphasizes the way they handle tablespaces as strongest point for ease of administration: http://www.sap.com/solutions/technology/sapdb/pdf/50033321.pdf Directory distribution explained in: http://www.sap.com/solutions/technology/sapdb/pdf/directorydistrib_72eng.pdf Architecture and tablespace/devspace concepts explained in: http://www.sap.com/solutions/technology/sapdb/pdf/dbmgui_73eng.pdf (721K) A good short overview can be obtained from the Glossary: http://www.sap.com/solutions/technology/sapdb/sap_db_glossary.htm (not .pdf - ordinary html) vvvvvvv data devspace The user data (tables, indexes) and the SQL catalog are stored in the data devspaces. A table or an index needs one page (minimum); a table can use all the data devspaces that is the whole database (maximum). A table increases or decreases in size automatically without administrative intervention. As a rule, a database internal striping algorithm distributes the data belonging to a table evenly across all the data devspaces. An assignment of tables to data devspaces is not possible nor is it necessary. When installing the database instance you can configure one or more data devspaces and while the database is running you can also add new data devspaces. The disk storage space defined by all the data devspaces is the total size of the database. devspace This term denotes a physical disk or part of a physical disk. This can be a raw device or a file. log devspace What is recorded in a log devspace is all the changes in the contents of the database, to enable the contents to be recovered or restored after hardware faults. The complete log can consist of a number of devspaces. You can define the number of log devspaces required when installing the database instance and can add new log devspaces even while the database is operating. To ensure that the data on the database is kept safe, you have the option of mirroring the log devspace(s) (set parameter LOG_MODE to DUAL). In log backups the contents of the log devspace(s) is copied to a file and the space originally occupied by it is released for log data. The backup files are numbered by the system in sequence. The selected size of the archive log devspace should therefore be sufficient for all the changes occurring between two backups to be recorded there. serverdb A Serverdb consists of the system devspace, one or more log devspaces, and one or more data devspaces. For security and performance reasons, each devspace type should be kept on a different disk. The log devspaces of a serverdb can also be mirrored to obtain a higher degree of availability. The disks used should present uniform performance data (especially access speeds) because this is the only way that equal usage of the devspaces can be achieved. If necessary, a database instance can be expanded by additional data devspaces while the database is running. The devspace usage level of a database instance is therefore a critical parameter of database operation and must be monitored. If the data devspaces become full, database operation stops. Further data devspaces can be defined in this state to allow database operation to continue. system devspace The restart information and the mapping of the logical page numbers to physical page addresses are administered in the system devspace. The size of the system devspace therefore depends directly on the database size and is determined by the database kernel. ^^^^^^^^^^^^^^^^^ Concept of just flexibly assigning space to databases, with only two types of space that should be kept on different spindlesets, plus the ability to add space *while running* is what justifies their claim to much easier admin than Oracle. Many Postgresql sites run with far too few spindles anyway and don't have DBAs with a clue what to do with tablespaces. Now that SAP DB is also open source, making it easy for them could be critically important. I'm not even subscribed to pgsql-hacker and don't understand the internals enough to have any view on whether it's possible or how. But if it is possible to present similar *concepts* to DBAs from the "outside", with whatever actually goes on internally, that would be really *great*. Once the internals are done, others could more easily add admin tools and documentation comparable to SAP DB. Given the overwhelming advantages of PostgreSQL from all other points of view, this could be critically important. I was surprised to find no discussion of comparisons with SAP DB and what could be learned from it's source release in a quick search of the web site and mailing lists. Seeya, Albert From pgsql-general-owner+M14288@postgresql.org Mon Aug 27 10:31:19 2001 Return-path: Received: from server1.pgsql.org (server1.pgsql.org [64.39.15.238]) by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id f7REVIF27112 for ; Mon, 27 Aug 2001 10:31:18 -0400 (EDT) Received: from postgresql.org.org (webmail.postgresql.org [216.126.85.28]) by server1.pgsql.org (8.11.6/8.11.6) with ESMTP id f7REVkq86991; Mon, 27 Aug 2001 09:31:47 -0500 (CDT) (envelope-from pgsql-general-owner+M14288@postgresql.org) Received: from svana.org (svana.org [210.9.66.30]) by postgresql.org (8.11.3/8.11.4) with ESMTP id f7RDcEf82291 for ; Mon, 27 Aug 2001 09:38:15 -0400 (EDT) (envelope-from kleptog@svana.org) Received: from kleptog by svana.org with local (Exim 3.12 #1 (Debian)) id 15bMal-0000Ac-00; Mon, 27 Aug 2001 23:38:15 +1000 Date: Mon, 27 Aug 2001 23:38:15 +1000 From: Martijn van Oosterhout To: newsreader@mediaone.net cc: Jeff Davis , pgsql-general@postgresql.org Subject: Re: [GENERAL] raw partition Message-ID: <20010827233815.B32309@svana.org> Reply-To: Martijn van Oosterhout References: <20010826125450.A11535@dragon.universe> <0GIP004VTV1MTO@mta7.pltn13.pbi.net> <20010827091141.A3208@dragon.universe> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010827091141.A3208@dragon.universe>; from newsreader@mediaone.net on Mon, Aug 27, 2001 at 09:11:41AM -0400 Precedence: bulk Sender: pgsql-general-owner@postgresql.org Status: OR On Mon, Aug 27, 2001 at 09:11:41AM -0400, newsreader@mediaone.net wrote: > On Mon, Aug 27, 2001 at 12:46:16AM -0700, Jeff Davis wrote: > > On Sunday 26 August 2001 09:54 am, you wrote: > > > > Obviously, if done properly, it couldn't hurt. However, is it really worth > > the extra trouble to set it up, and more so, to debug an extra form that disk > > I think it's only a matter of getting rid > of file system layer. But that won't work. Postgres currently stores each table in its own file. Thus, to implement raw access postgres would have to implement it's own filesystem within the raw partition. By using the filesystems built into the OS, it can take advantage of filesystem smarts already there. No to mention people just being able to use normal system commands to view what's there e.g. symlinks to relocate tables. I beleive that filesystem technology within the OS will advance much faster than anything the postgres developers could come up with. For example, by running your database on an ext3 partition, all file metadata is automatically journalled, with no additional effort from the postgres developers. You could even choose to journal all database access (though I have no idea how that interacts with WAL). > > marginal utility for integrated functionality? Consider this: should postgres > > be it's own OS; bootable and everything (get rid of all that OS overhead)? I > > file system overhead is all, I think. > The only thing I am sure about is that > whether pg (and developers) will have to be > aware of the disk technology since it is > evolving continuosly. Or is there another > layer provided by the OS: a layer > between physical disk and the filesystem? > That layer will have to understand UDMA technology, > SCSI technology? I have no idea. Well, a raw partition provided by the OS would hide such details. However, postgres would have to make assumptions about what kind of access patterns are optimal. The kernel is in a much better position to make such decisions about resource usage. Which is precisly why we have OS's in the first place. > > oracle allows this behaviour you speak of, but I have never used it. Does > > someone have experience (or benchmarks or whatever) with oracle's > > implementation? > > I have never used an oracle I beleive (someone correct me if I'm wrong) that even when used on a filesystem, oracle still places all it's tables in a single file i.e. it has a filesystem layer builtin. I think that's why it's a clear win for oracle because you *are* actually removing a layer. IMHO it's something postgres should stay well away from. -- Martijn van Oosterhout http://svana.org/kleptog/ > It would be nice if someone came up with a certification system that > actually separated those who can barely regurgitate what they crammed over > the last few weeks from those who command secret ninja networking powers. ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)