From 2ffba0d498177492dc68a6456e250be100a4f857 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Wed, 29 Jan 1997 05:26:59 +0000 Subject: [PATCH] Changes to get ready for 6.0 final release. --- HISTORY | 6 +- doc/FAQ | 1872 +++++++++++++++++++++++------------------------------- doc/TODO | 14 +- 3 files changed, 826 insertions(+), 1066 deletions(-) diff --git a/HISTORY b/HISTORY index 60f508807c..bad1d32711 100644 --- a/HISTORY +++ b/HISTORY @@ -1,4 +1,4 @@ -PostgreSQL 6.0 beta Thu Dec 26 16:47:43 EST 1996 +PostgreSQL 6.0 Wed Jan 29 00:19:54 EST 1997 ------------------------------------------------------------- A dump/restore is required for those wishing to migrate data from @@ -68,6 +68,7 @@ Allow restriction on who can do backend COPY(Bryan) Can shrink tables, pg_time and pg_log(Vadim & Erich) Change debug level 2 to print queries only, changed debug heading layout(Bruce) Change default decimal constant representation from float4 to float8(Bruce) +European date format now set when postmaster is started Execute lowercase function names if not found with exact case Fixes for aggregate/GROUP processing, allow 'select sum(func(x),sum(x+y) from z' Gist now included in the distrubution(Marc) @@ -79,7 +80,7 @@ Libpq++ improvements New options to initdb(Bryan) Pg_dump allow dump of oid's(Bruce) Pg_dump create indexes after tables are loaded for speed(Bruce) -Pg_dump(Bruce) +Pg_dumpall dumps all databases, and the user table Pginterface additions for NULL values(Bruce) Prevent postmaster from being run as root Psql \h and \? is now readable(Bruce) @@ -94,6 +95,7 @@ Remove compile-time parameters to enable binary distributions(Bryan) Reverse meaning of HBA masks(Bryan) Secure Authentication of local users(Bryan) Speed up vacuum(Vadim) +Vacuum now had VERBOSE option(Bruce) Source tree changes ------------------- diff --git a/doc/FAQ b/doc/FAQ index d8b95a180b..ce96f1d13c 100644 --- a/doc/FAQ +++ b/doc/FAQ @@ -1,544 +1,422 @@ +Frequently Asked Questions (FAQ) for PostgreSQL + +Last updated: Tue Jan 28 20:08:25 EST 1997 +Version: 6.0 + +Current maintainer: Bruce Momjian (maillist@candle.pha.pa.us) + +The most recent version of this document can be viewed at the postgreSQL Web +site, http://postgreSQL.org. + +Linux-specific questions are answered in +http://postgreSQL.org/docs/FAQ-Linux.phtml. + +Irix-specific questions are answered in +http://postgreSQL.org/docs/FAQ-Irix.phtml. + +Changes in this version (* = modified, + = new): + + * *1.1) What is PostgreSQL? + * *1.5) Support for PostgreSQL + * *1.6) Latest release of PostgreSQL + * *1.10 Does PostgreSQL work with databases from earlier versions of + postgres? + * *3.1) How do I specify a KEY or other constraints on a column? + * *3.3) How do I define a unique indices? + * *3.11) Why doesn't the != operator work? + * *3.26) Why are my table files not getting any smaller after a delete? + * *3.28) I get the error 'default index class unsupported' when creating + an index. How do I do it? + * *3.37) What is the time-warp feature and how does it relate to vacuum? + * *5.1) How do I make a bug report? + +---------------------------------------------------------------------------- - html> - - FREQUENTLY ASKED QUESTIONS (FAQ) FOR POSTGRESQL - - - - Last updated: Thu Dec 12 21:30:37 EST 1996 - Version: 6.0 - - Current maintainer: Bruce Momjian (maillist@candle.pha.pa.us) - - - The most recent version of this document can be viewed at the - postgreSQL Web site, http://postgreSQL.org. - - Linux-specific questions are answered in - http://postgreSQL.org/docs/FAQ-Linux.phtml. - - Irix-specific questions are answered in - http://postgreSQL.org/docs/FAQ-Irix.phtml. - - Changes in this version (* = modified, + = new): - - *1.1) What is PostgreSQL? - - *1.5) Support for PostgreSQL - - *1.6) Latest release of PostgreSQL - - *1.10 Does PostgreSQL work with databases from earlier versions of - postgres? - - *3.1) How do I specify a KEY or other constraints on a column? - - *3.3) How do I define a unique indices? - - *3.11) Why doesn't the != operator work? - - *3.26) Why are my table files not getting any smaller after a delete? - - *3.28) I get the error 'default index class unsupported' when creating - an index. How do I do it? - - *3.37) What is the time-warp feature and how does it relate to vacuum? - - *5.1) How do I make a bug report? - _________________________________________________________________ - - - Questions answered: - 1) General questions - - 1.1) What is PostgreSQL? - 1.2) What does PostgreSQL run on? - 1.3) Where can I get PostgreSQL? - 1.4) What's the copyright on PostgreSQL? - 1.5) Support for PostgreSQL - 1.6) Latest release of PostgreSQL - 1.7) Is there a commercial version of PostgreSQL? - 1.9) What version of SQL does PostgreSQL use? - 1.10) Does PostgreSQL work with databases from earlier versions of - postgres? - 1.11) How many people use PostgreSQL? - - 2) Installation questions - - 2.1) initdb doesn't run - 2.2) when I start up the postmaster, I get "FindBackend: could not - find a backend to execute..." "postmaster: could not find backend to - execute..." - 2.3) The system seems to be confused about commas, decimal points, and - date formats. - 2.4) How do I install PostgreSQL somewhere other than - /usr/local/pgsql? - 2.5) The backend compiled successfully, but compiling libpq resulted - in a complaint: "libpq/pqcomm.h" not found when compiling fe-auth.c. - 2.6) When I run postmaster, I get a Bad System Call core dumped - message. - 2.7) When I try to start the postmaster, I get IpcMemoryCreate errors. - 2.8) I have changed a source file, but a recompile does not see the - change. - - 3) PostgreSQL Features questions - - 3.1) How do I specify a KEY or other constraints on a column? - 3.2) Does PostgreSQL support nested subqueries? - 3.3) How do I define a unique indices? - 3.4) I've having a lot of problems using rules. - 3.5) I can't seem to write into the middle of large objects reliably. - 3.6) Does PostgreSQL have a graphical user interface? A report - generator? A embedded query language interface? - 3.7) How can I write client applications to PostgreSQL? - 3.8) How do I prevent other hosts from accessing my PostgreSQL - 3.9) How do I set up a pg_group? - 3.10) What is the exact difference between binary cursors and normal - cursors? - 3.11) Why doesn't the != operator work? - 3.12) What is a R-tree index and what is it used for? - 3.13) What is the maximum size for a tuple? - 3.14) I defined indices but my queries don't seem to make use of them. - Why? - 3.15) Are there ODBC drivers for PostgreSQL? - 3.16) How do I use postgres for multi-dimensional indexing (> 2 - dimensions)? - 3.17) How do I do regular expression searches? case-insensitive regexp - searching? - 3.18) I can't access the database as the 'root' user. - 3.19) I experienced a server crash during a vacuum. How do I remove - the lock file? - 3.20) What is the difference between the various character types? - 3.21) In a query, how do I detect if a field is NULL? - 3.22) How do I see how the query optimizer is evaluating my query? - 3.23) How do I create a serial field? - 3.24) How do I create a multi-column index? - 3.25) What are the temp_XXX files in my database directory? - 3.26) Why are my table files not getting any smaller after a delete? - 3.27) Why can't I connect to my database from another machine? - 3.28) I get the error 'default index class unsupported' when creating - an index. How do I do it? - 3.29) Why does creating an index crash the backend server? - 3.30) How do I specify a decimal constant as a float8, or a string as - a text? Why am I getting poor precision? - 3.31) How do I find out what indexes or operations are defined in the - database? - 3.32) My database is corrupt. I can't do anything. What should I do? - 3.33) Createdb, destroydb, createuser, destroyuser don't run. Why? - 3.34) Why does 'createuser' return 'unexpected last match in input()'? - 3.35) All my servers crash under concurrent table access. Why? - 3.36) What tools are available for hooking postgres to Web pages? - 3.37) What is the time-warp feature and how does it relate to vacuum? - 3.38) How do I tune the database engine for better performance? - 3.39) What debugging features are available in PostgreSQL? - 3.40) What is an oid? What is a tid? - 3.41) What is the meaning of some of the terms used in Postgres? - - 4) Questions about extending PostgreSQL - - 4.1) I wrote a user-defined function and when I run it in psql, it - dumps core. - 4.2) I get messages of the type NOTICE:PortalHeapMemoryFree: - 0x402251d0 - 4.3) I've written some nifty new types and functions for PostgreSQL. - 4.4) How do I write a C function to return a tuple? - - 5) Bugs - - 5.1) How do I make a bug report? - _________________________________________________________________ - +1) General questions + +1.1) What is PostgreSQL? +1.2) What does PostgreSQL run on? +1.3) Where can I get PostgreSQL? +1.4) What's the copyright on PostgreSQL? +1.5) Support for PostgreSQL +1.6) Latest release of PostgreSQL +1.7) Is there a commercial version of PostgreSQL? +1.9) What version of SQL does PostgreSQL use? +1.10) Does PostgreSQL work with databases from earlier versions of postgres? +1.11) How many people use PostgreSQL? + +2) Installation questions + +2.1) initdb doesn't run +2.2) when I start up the postmaster, I get "FindBackend: could not find a +backend to execute..." "postmaster: could not find backend to execute..." +2.3) The system seems to be confused about commas, decimal points, and date +formats. +2.4) How do I install PostgreSQL somewhere other than /usr/local/pgsql? +2.5) When I run postmaster, I get a Bad System Call core dumped message. +2.6) When I try to start the postmaster, I get IpcMemoryCreate errors. +2.7) I have changed a source file, but a recompile does not see the change. +2.8) I have changed a source file, but a recompile does not see the change? +3.1) How do I specify a KEY or other constraints on a column? +3.2) Does PostgreSQL support nested subqueries? +3.3) How do I define a unique indices? +3.4) I've having a lot of problems using rules. +3.5) I can't seem to write into the middle of large objects reliably. +3.6) Does PostgreSQL have a graphical user interface? A report generator? A +embedded query language interface? +3.7) How can I write client applications to PostgreSQL? +3.8) How do I prevent other hosts from accessing my PostgreSQL +3.9) How do I set up a pg_group? +3.10) What is the exact difference between binary cursors and normal +cursors? +3.11) Why doesn't the != operator work? +3.12) What is a R-tree index and what is it used for? +3.13) What is the maximum size for a tuple? +3.14) I defined indices but my queries don't seem to make use of them. Why? +3.15) Are there ODBC drivers for PostgreSQL? +3.16) How do I use postgres for multi-dimensional indexing (> 2 dimensions)? +3.17) How do I do regular expression searches? case-insensitive regexp +searching? +3.18) I can't access the database as the 'root' user. +3.19) I experienced a server crash during a vacuum. How do I remove the lock +file? +3.20) What is the difference between the various character types? +3.21) In a query, how do I detect if a field is NULL? +3.22) How do I see how the query optimizer is evaluating my query? +3.23) How do I create a serial field? +3.24) How do I create a multi-column index? +3.25) What are the temp_XXX files in my database directory? +3.26) Why are my table files not getting any smaller after a delete? +3.27) Why can't I connect to my database from another machine? +3.28) I get the error 'default index class unsupported' when creating an +index. How do I do it? +3.29) Why does creating an index crash the backend server? +3.30) How do I specify a decimal constant as a float8, or a string as a +text? Why am I getting poor precision? +3.31) How do I find out what indexes or operations are defined in the +database? +3.32) My database is corrupt. I can't do anything. What should I do? +3.33) Createdb, destroydb, createuser, destroyuser don't run. Why? +3.34) Why does 'createuser' return 'unexpected last match in input()'? +3.35) All my servers crash under concurrent table access. Why? +3.36) What tools are available for hooking postgres to Web pages? +3.37) What is the time-warp feature and how does it relate to vacuum? +3.38) How do I tune the database engine for better performance? +3.39) What debugging features are available in PostgreSQL? +3.40) What is an oid? What is a tid? +3.41) What is the meaning of some of the terms used in Postgres? + +4) Questions about extending PostgreSQL + +4.1) I wrote a user-defined function and when I run it in psql, it dumps +core. +4.2) I get messages of the type NOTICE:PortalHeapMemoryFree: 0x402251d0 +4.3) I've written some nifty new types and functions for PostgreSQL. +4.4) How do I write a C function to return a tuple? + +5) Bugs + +5.1) How do I make a bug report? +---------------------------------------------------------------------------- + Section 1: General Questions - 1.1) What is PostgreSQL? - - - - PostgreSQL is an enhancement of the POSTGRES database management - system, a next-generation DBMS research prototype. While PostgreSQL - retains the powerful data model and rich data types of POSTGRES, it - replaces the PostQuel query language with an extended subset of SQL. - PostgreSQL is free and the complete source is available. - - PostgreSQL development is being performed by a team of Internet - developers who all subscribe to the PostgreSQL development mailing - list. The current coordinator is Marc G. Fournier - (scrappy@postgreSQL.org). (See below on how to join). This team is - now responsible for all current and future development of PostgreSQL. - - The authors of PostgreSQL 1.01 were Andrew Yu and Jolly Chen. Many - others have contributed to the porting, testing, debugging and - enhancement of the code. The original Postgres code, from which - PostgreSQL is derived, was the effort of many graduate students, - undergraduate students, and staff programmers working under the - direction of Professor Michael Stonebraker at the University of - California, Berkeley. - - The original name of the software at Berkeley was Postgres. When SQL - functionality was added in 1995, its name was changed to Postgres95. - The name was changed at the end of 1996 to PostgreSQL. - - 1.2) What does PostgreSQL run on? - - - - The authors have compiled and tested PostgreSQL on the following - platforms(some of these compiles require gcc 2.7.0): - * DEC Alpha AXP on OSF/1 2.0 - * HP PA-RISC on HP-UX 9.0 - * i386 Solaris - * SUN SPARC on Solaris 2.4 - * SUN SPARC on SunOS 4.1.3 - * DEC MIPS on Ultrix 4.4 - * Intel x86 on Linux 1.2 and Linux ELF - * OSs derived from 4.4-lite BSD (NetBSD, FreeBSD) - * IBM on AIX 3.2.5 - * BSD/OS 2.0, 2.01 & 2.1 - * SGI MIPS on IRIX 5.3 - - - - The following ports are bundled with the PostgreSQL distribution. The - authors do not have handy access to these platforms but the ports have - been tested by the others. - * Motorola MC68K or Intel x86 on NeXTSTEP 3.2 - * Intel x86 on Intel SVR4 - - - - 1.3) Where can I get PostgreSQL? - - - - The primary anonymous ftp site for PostgreSQL is: - * ftp://ftp.postgreSQL.org/pub - - - - A mirror site exists at: - * ftp://postgres95.vnet.net/pub/postgres95 - * ftp://ftp.luga.or.at/pub/postgres95 - * ftp://cal011111.student.utwente.nl/pub/postgres95 - * ftp://ftp.uni-trier.de/pub/database/rdbms/postgres/postgres95 - * ftp://rocker.sch.bme.hu - - 1.4) What's the copyright on PostgreSQL? - - - - PostgreSQL is subject to the following COPYRIGHT. - - PostgreSQL Data Base Management System - - Copyright (c) 1994-6 Regents of the University of California - - Permission to use, copy, modify, and distribute this software and its - documentation for any purpose, without fee, and without a written - agreement is hereby granted, provided that the above copyright notice - and this paragraph and the following two paragraphs appear in all - copies. - - IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY - FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, - INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND - ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN - ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - - THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, - INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF - MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE - PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF - CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, - UPDATES, ENHANCEMENTS, OR MODIFICATIONS. - - 1.5) Support for PostgreSQL - - - - There is no official support for PostgreSQL from the original - maintainers or from University of California, Berkeley. It is - maintained through volunteer effort only. - - The main mailing list is: questions@postgreSQL.org. It is available - for discussion o f matters pertaining to PostgreSQL, including but not - limited to bug reports and fixes. For info on how to subscribe, send a - mail with the lines in the body (not the subject line) +1.1) What is PostgreSQL? +PostgreSQL is an enhancement of the POSTGRES database management system, a +next-generation DBMS research prototype. While PostgreSQL retains the +powerful data model and rich data types of POSTGRES, it replaces the +PostQuel query language with an extended subset of SQL. PostgreSQL is free +and the complete source is available. - help - info questions +PostgreSQL development is being performed by a team of Internet developers +who all subscribe to the PostgreSQL development mailing list. The current +coordinator is Marc G. Fournier (scrappy@postgreSQL.org). (See below on how +to join). This team is now responsible for all current and future +development of PostgreSQL. - - - to majordomo@postgreSQL.org. - - There is also a digest list available. To subscribe to this list, send - email to: majordomo@postgreSQL.org with a BODY of: +The authors of PostgreSQL 1.01 were Andrew Yu and Jolly Chen. Many others +have contributed to the porting, testing, debugging and enhancement of the +code. The original Postgres code, from which PostgreSQL is derived, was the +effort of many graduate students, undergraduate students, and staff +programmers working under the direction of Professor Michael Stonebraker at +the University of California, Berkeley. +The original name of the software at Berkeley was Postgres. When SQL +functionality was added in 1995, its name was changed to Postgres95. The +name was changed at the end of 1996 to PostgreSQL. - subscribe questions-digest +1.2) What does PostgreSQL run on? - Digests are sent out to members of this list whenever the main list - has received around 30k of messages. - - There is also a developers mailing list available. To subscribe to - this list, send email to hackers-request@postgreSQL.org with a BODY - of: - +The authors have compiled and tested PostgreSQL on the following +platforms(some of these compiles require gcc 2.7.0): + * aix - IBM on AIX 3.2.5 + * alpha - DEC Alpha AXP on OSF/1 2.0 + * BSD44_derived - OSs derived from 4.4-lite BSD (NetBSD, FreeBSD) + * bsdi - BSD/OS 2.0, 2.01, 2.1 + * dgux - DG/UX 5.4R3.10 + * hpux - HP PA-RISC on HP-UX 9.0 + * i386_solaris - i386 Solaris + * irix5 - SGI MIPS on IRIX 5.3 + * linux - Intel x86 on Linux 1.2 and Linux ELF (For non-ELF Linux, see + LINUX_ELF below). + * next - Motorola MC68K or Intel x86 on NeXTSTEP 3.2 + * sparc_solaris - SUN SPARC on Solaris 2.4 + * sunos4 - SUN SPARC on SunOS 4.1.3 + * svr4 - Intel x86 on Intel SVR4 + * ultrix4 - DEC MIPS on Ultrix 4.4 - subscribe hackers +1.3) Where can I get PostgreSQL? + +The primary anonymous ftp site for PostgreSQL is: + + * ftp://ftp.postgreSQL.org/pub + +A mirror site exists at: + + * ftp://postgres95.vnet.net/pub/postgres95 + * ftp://ftp.luga.or.at/pub/postgres95 + * ftp://cal011111.student.utwente.nl/pub/postgres95 + * ftp://ftp.uni-trier.de/pub/database/rdbms/postgres/postgres95 + * ftp://rocker.sch.bme.hu + +1.4) What's the copyright on PostgreSQL? + +PostgreSQL is subject to the following COPYRIGHT. + +PostgreSQL Data Base Management System + +Copyright (c) 1994-6 Regents of the University of California + +Permission to use, copy, modify, and distribute this software and its +documentation for any purpose, without fee, and without a written agreement +is hereby granted, provided that the above copyright notice and this +paragraph and the following two paragraphs appear in all copies. + +IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR +DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING +LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, +EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF +SUCH DAMAGE. + +THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, +INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND +FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN +"AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO +PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + +1.5) Support for PostgreSQL + +There is no official support for PostgreSQL from the original maintainers or +from University of California, Berkeley. It is maintained through volunteer +effort only. + +The main mailing list is: questions@postgreSQL.org. It is available for +discussion o f matters pertaining to PostgreSQL, including but not limited +to bug reports and fixes. For info on how to subscribe, send a mail with the +lines in the body (not the subject line) + + subscribe + end + +to questions-request@postgreSQL.org. + +There is also a digest list available. To subscribe to this list, send email +to: questions-digest-request@postgreSQL.org with a BODY of: + + subscribe + end + +Digests are sent out to members of this list whenever the main list has +received around 30k of messages. + +There is a bugs mailing list available. To subscribe to this list, send +email to bugs-request@postgreSQL.org with a BODY of: + +There is also a developers discussion mailing list available. To subscribe +to this list, send email to hackers-request@postgreSQL.org with a BODY of: + + subscribe + end + +Additional information about PostgreSQL can be found via the PostgreSQL WWW +home page at: - - - Additional information about PostgreSQL can be found via the - PostgreSQL WWW home page at: - http://postgreSQL.org - - - - 1.6) Latest release of PostgreSQL - - - - The latest release of PostgreSQL is version 1.09. The next release - will be numbered 6.0 for historical reasons. This release is in beta - and is available at our ftp site. We expect the beta period to be - complete during the week of January 2, 1997. For information about - what is new in 6.0, see our TODO list on our WWW page. - - We expect a 7.0 release in several months that will remove time-travel - and reduce by 50% the size of on-disk system columns maintained for - each row in a table. This release will also require a dump and - restore. - - 1.7) Is there a commercial version of PostgreSQL? - - - - Illustra Information Technology (a wholly owned subsidiary of Informix - Software, Inc.) sells an object-relational DBMS called Illustra that - was originally based on postgres. Illustra has cosmetic similarities - to PostgreSQL but has more features, is more robust, performs better, - and offers real documentation and support. On the flip side, it costs - money. For more information, contact sales@illustra.com - - 1.8) What documentation is available for PostgreSQL? - - - - A user manual, manual pages, and some small test examples are included - in the distribution. The sql and built-in manual pages are - particularly important. - - The www page contains pointers to an implementation guide and five - papers written about postgres design concepts and features. - - 1.9) What version of SQL does PostgreSQL use? - - - - PostgreSQL supports a subset of SQL-92. It has most of the important - constructs but lacks some of the functionality. The most visible - differences are: - * no support for nested subqueries - * no HAVING clause under a GROUP BY - - - - On the other hand, you get to create user-defined types, functions, - inheritance etc. If you're willing to help with PostgreSQL coding, - eventually we can also add the missing features listed above. - - 1.10) Does PostgreSQL work with databases from earlier versions of postgres? - - - - PostgreSQL v1.09 is compatible with databases created with v1.01. - Those upgrading from 1.0 should read the directions in the - MIGRATION_1.0_TO_1.02 directory. - - Upgrading to 6.0 requires a dump and restore. - - 1.11) How many people use PostgreSQL? - - - - Since we don't have any licensing or registration scheme, it's - impossible to tell. We do know hundreds copies of PostgreSQL v1.* have - been downloaded, and that there many hundreds of subscribers to the - mailing lists. - - - _________________________________________________________________ - -Section 2: Installation Questions - - - 2.1) initdb doesn't run - - - - * check to see that you have the proper paths set - * check that the 'postgres' user owns all the right files - * ensure that there are files in $PGDATA/files, and that they are - non-empty. If they aren't, then "gmake install" failed for some - reason - - - - 2.2) when I start up the postmaster, I get "FindBackend: could not find a - backend to execute..." "postmaster: could not find backend to execute..." - - - - You probably do not have the right path set up. The 'postgres' - executable needs to be in your path. - - 2.3) The system seems to be confused about commas, decimal points, and date - formats. - - - - Check your locale configuration. PostgreSQL uses the locale settings - of the user that ran the postmaster process. Set those accordingly for - your operating environment. - - 2.4) How do I install PostgreSQL somewhere other than /usr/local/pgsql? - - - - You need to manually edit the paths in src/Makefile.global to your - site configuration. - - 2.5) The backend compiled successfully, but compiling libpq resulted in a - complaint: "libpq/pqcomm.h" not found when compiling fe-auth.c. - - - - You've probably installed PostgreSQL somewhere other than - /usr/local/pgsql, but didn't edit the src/Makefile.global accordingly. - See question 2.6. - - 2.6) When I run postmaster, I get a Bad System Call core dumped message. - - - - It could be a variety of problems, but first check to see that you - have system V extensions installed on your kernel. PostgreSQL requires - kernel support for shared memory. - - 2.7) I get the error message "obj/fmgr.h: No such file or directory" - - - - This indicates that you did not generate the file fmgr.h properly. - Something failed in the running of the - src/backend/utils/Gen_fmgrtab.sh script. Check to see the paths used - in that script is appropriate to your system. - - 2.8) When I try to start the postmaster, I get IpcMemoryCreate errors. - - - - You either do not have shared memory configured properly in kernel or - you need to enlarge the shared memory available in the kernel. The - exact amount you need depends on your architecture and how many - buffers you configure postmaster to run with. For most systems, with - default buffer sizes, you need a minimum of ~760K. - - 2.10) I have changed a source file, but a recompile does not see the change? - - - - The Makefiles do not have the proper dependencies for include files. - You have to do a 'make clean' and then another 'make'. - - - _________________________________________________________________ - -Section 3: PostgreSQL Features +1.6) Latest release of PostgreSQL - - - 3.1) How do I specify a KEY or other constraints on a column? - - - - Column constraints are not supported in PostgreSQL. As a consequence, - the system does not check for duplicates. - - Under 6.0, create a unique index on the column. Attempts to create - duplicate of that column will report an error. - - 3.2) Does PostgreSQL support nested subqueries? - - - - Subqueries are not implemented, but they can be simulated using sql - functions. - - 3.3) How do I define a unique indices? - - - - PostgreSQL 6.0 supports unique indices. - - 3.4) I've having a lot of problems using rules. - - - - Currently, the rule system in PostgreSQL is mostly broken. It works - enough to support the view mechanism, but that's about it. Use - PostgreSQL rules at your own peril. - - 3.5) I can't seem to write into the middle of large objects reliably. - - - - The Inversion large object system in PostgreSQL is also mostly broken. - It works well enough for storing large wads of data and reading them - back out, but the implementation has some underlying problems. Use - PostgreSQL large objects at your own peril. - - 3.6) Does PostgreSQL have a graphical user interface? A report generator? A - embedded query language interface? - - - - No. No. No. Not in the official distribution at least. Some users have - reported some success at using 'pgbrowse' and 'onyx' as frontends to - PostgreSQL. Several contributions are working on tk based frontend - tools. Ask on the mailing list. - - 3.7) How can I write client applications to PostgreSQL? - - - - PostgreSQL supports a C-callable library interface called libpq as - well as a Tcl-based library interface called libtcl. - - Others have contributed a perl interface and a WWW gateway to - PostgreSQL. See the PostgreSQL home pages for more details. - - 3.8) How do I prevent other hosts from accessing my PostgreSQL backend? - - - - Use host-based authentication by modifying the file $PGDATA/pg_hba - accordingly. - - 3.9) How do I set up a pg_group? - - - - Currently, there is no easy interface to set up user groups. You have - to explicitly insert/update the pg_group table. For example: +The latest release of PostgreSQL is version 1.09. The next release will be +numbered 6.0 for historical reasons. This release is in beta and is +available at our ftp site. We expect the beta period to be complete during +the week of January 31, 1997. For information about what is new in 6.0, see +our TODO list on our WWW page. +We expect a 7.0 release in several months that will remove time-travel and +reduce by 50% the size of on-disk system columns maintained for each row in +a table. This release will also require a dump and restore. + +1.7) Is there a commercial version of PostgreSQL? + +Illustra Information Technology (a wholly owned subsidiary of Informix +Software, Inc.) sells an object-relational DBMS called Illustra that was +originally based on postgres. Illustra has cosmetic similarities to +PostgreSQL but has more features, is more robust, performs better, and +offers real documentation and support. On the flip side, it costs money. For +more information, contact sales@illustra.com + +1.8) What documentation is available for PostgreSQL? + +A user manual, manual pages, and some small test examples are included in +the distribution. The sql and built-in manual pages are particularly +important. + +The www page contains pointers to an implementation guide and five papers +written about postgres design concepts and features. + +1.9) What version of SQL does PostgreSQL use? + +PostgreSQL supports a subset of SQL-92. It has most of the important +constructs but lacks some of the functionality. The most visible differences +are: + + * no support for nested subqueries + * no HAVING clause under a GROUP BY + +On the other hand, you get to create user-defined types, functions, +inheritance etc. If you're willing to help with PostgreSQL coding, +eventually we can also add the missing features listed above. + +1.10) Does PostgreSQL work with databases from earlier versions of postgres? + +PostgreSQL v1.09 is compatible with databases created with v1.01. Those +upgrading from 1.0 should read the directions in the MIGRATION_1.0_TO_1.02 +directory. + +Upgrading to 6.0 requires a dump and restore. + +1.11) How many people use PostgreSQL? + +Since we don't have any licensing or registration scheme, it's impossible to +tell. We do know hundreds copies of PostgreSQL v1.* have been downloaded, +and that there many hundreds of subscribers to the mailing lists. + +---------------------------------------------------------------------------- + +Section 2: Installation Questions + +2.1) initdb doesn't run + + * check to see that you have the proper paths set + * check that the 'postgres' user owns all the right files + * ensure that there are files in $PGDATA/files, and that they are + non-empty. If they aren't, then "gmake install" failed for some reason + +2.2) when I start up the postmaster, I get "FindBackend: could not find a +backend to execute..." "postmaster: could not find backend to execute..." + +You probably do not have the right path set up. The 'postgres' executable +needs to be in your path. + +2.3) The system seems to be confused about commas, decimal points, and date +formats. + +Check your locale configuration. PostgreSQL uses the locale settings of the +user that ran the postmaster process. Set those accordingly for your +operating environment. + +2.4) How do I install PostgreSQL somewhere other than /usr/local/pgsql? + +You need to edit Makefile.global and change POSTGRESDIR accordingly, or +create a Makefile.custom and define POSTGRESDIR there. + +2.5) When I run postmaster, I get a Bad System Call core dumped message. + +It could be a variety of problems, but first check to see that you have +system V extensions installed on your kernel. PostgreSQL requires kernel +support for shared memory. + +2.6) I get the error message "obj/fmgr.h: No such file or directory" + +This indicates that you did not generate the file fmgr.h properly. Something +failed in the running of the src/backend/utils/Gen_fmgrtab.sh script. Check +to see the paths used in that script is appropriate to your system. + +2.7) When I try to start the postmaster, I get IpcMemoryCreate errors. + +You either do not have shared memory configured properly in kernel or you +need to enlarge the shared memory available in the kernel. The exact amount +you need depends on your architecture and how many buffers you configure +postmaster to run with. For most systems, with default buffer sizes, you +need a minimum of ~760K. + +2.8) I have changed a source file, but a recompile does not see the change? + +The Makefiles do not have the proper dependencies for include files. You +have to do a 'make clean' and then another 'make'. + +---------------------------------------------------------------------------- + +Section 3: PostgreSQL Features + +3.1) How do I specify a KEY or other constraints on a column? + +Column constraints are not supported in PostgreSQL. As a consequence, the +system does not check for duplicates. + +Under 6.0, create a unique index on the column. Attempts to create duplicate +of that column will report an error. + +3.2) Does PostgreSQL support nested subqueries? + +Subqueries are not implemented, but they can be simulated using sql +functions. + +3.3) How do I define a unique indices? + +PostgreSQL 6.0 supports unique indices. + +3.4) I've having a lot of problems using rules. + +Currently, the rule system in PostgreSQL is mostly broken. It works enough +to support the view mechanism, but that's about it. Use PostgreSQL rules at +your own peril. + +3.5) I can't seem to write into the middle of large objects reliably. + +The Inversion large object system in PostgreSQL is also mostly broken. It +works well enough for storing large wads of data and reading them back out, +but the implementation has some underlying problems. Use PostgreSQL large +objects at your own peril. + +3.6) Does PostgreSQL have a graphical user interface? A report generator? A +embedded query language interface? + +No. No. No. Not in the official distribution at least. Some users have +reported some success at using 'pgbrowse' and 'onyx' as frontends to +PostgreSQL. Several contributions are working on tk based frontend tools. +Ask on the mailing list. + +3.7) How can I write client applications to PostgreSQL? + +PostgreSQL supports a C-callable library interface called libpq as well as a +Tcl-based library interface called libtcl. + +Others have contributed a perl interface and a WWW gateway to PostgreSQL. +See the PostgreSQL home pages for more details. + +3.8) How do I prevent other hosts from accessing my PostgreSQL backend? + +Use host-based authentication by modifying the file $PGDATA/pg_hba +accordingly. + +3.9) How do I set up a pg_group? + +Currently, there is no easy interface to set up user groups. You have to +explicitly insert/update the pg_group table. For example: jolly=> insert into pg_group (groname, grosysid, grolist) jolly=> values ('posthackers', '1234', '{5443, 8261}'); @@ -547,180 +425,145 @@ Section 3: PostgreSQL Features CHANGE jolly=> - - - The fields in pg_group are: - * groname: the group name. This a char16 and should be purely - alphanumeric. Do not include underscores or other punctuation. - * grosysid: the group id. This is an int4. This should be unique for - each group. - * grolist: the list of pg_user id's that belong in the group. This - is an int4[]. - - - - 3.10) What is the exact difference between binary cursors and normal cursors? - - - - Normal cursors return data back in ASCII format. Since data is stored - natively in binary format, the system must do a conversion to produce - the ASCII format. In addition, ASCII formats are often large in size - than binary format. Once the attributes come back in ASCII, often the - client application then has to convert it to a binary format to - manipulate it anyway. - - Binary cursors give you back the data in the native binary - representation. Thus, binary cursors will tend to be a little faster - since there's less overhead of conversion. - - However, ASCII is architectural neutral whereas binary representation - can differ between different machine architecture. Thus, if your - client machine uses a different representation than you server - machine, getting back attributes in binary format is probably not what - you want. Also, if your main purpose is displaying the data in ASCII, - then getting it back in ASCII will save you some effort on the client - side. - - 3.11) Why doesn't the != operator work? - - - - SQL specifies <> as the inequality operator, and that is what we have - defined for the built-in types. - - In 6.0, != is equivalent to <>. - - 3.12) What is a R-tree index and what is it used for? - - - - An r-tree index is used for indexing spatial data. A hash index can't - handle range searches. A B-tree index only handles range searches in a - single dimension. R-tree's can handle multi-dimensional data. For - example, if a R-tree index can be built on an attribute of type - 'point', the system can more efficient answer queries like select all - points within a bounding rectangle. - - The canonical paper that describes the original R-Tree design is: - - Guttman, A. "R-Trees: A Dynamic Index Structure for Spatial - Searching." Proc of the 1984 ACM SIGMOD Int'l Conf on Mgmt of Data, - 45-57. - - You can also find this paper in Stonebraker's "Readings in Database - Systems" - - 3.13) What is the maximum size for a tuple? - - - - Tuples are limited to 8K bytes. Taking into account system attributes - and other overhead, one should stay well shy of 8,000 bytes to be on - the safe side. To use attributes larger than 8K, try using the large - objects interface. - - Tuples do not cross 8k boundaries so a 5k tuple will require 8k of - storage. - - 3.14) I defined indices but my queries don't seem to make use of them. Why? - - - - PostgreSQL does not automatically maintain statistics. One has to make - an explicit 'vacuum' call to update the statistics. After statistics - are updated, the optimizer has a better shot at using indices. Note - that the optimizer is limited and does not use indices in some - circumstances (such as OR clauses). - - If the system still does not see the index, it is probably because you - have created an index on a field with the improper *_ops type. For - example, you have created a CHAR(4) field, but have specified a - char_ops index type_class. - - See the create_index manual page for information on what type classes - are available. It must match the field type. - - Postgres does not warn the user when the improper index is created. - - Indexes not used for ORDER BY operations. - - 3.15) Are there ODBC drivers for PostgreSQL? - - - - There are two ODBC drivers available, PostODBC and OpenLink ODBC. - - For all people being interested in PostODBC, there are now two mailing - lists devoted to the discussion of PostODBC. The mailing lists are: - * postodbc-users@listserv.direct. net - * postodbc-developers@listse rv.direct.net - - - - these lists are ordinary majordomo mailing lists. You can subscribe by - sending a mail to: - * majordomo@listserv.direct.net - - - - OpenLink ODBC is currently in beta under Linux. You can get it from - http://www.openlinksw.com/postgres.html. It works with our standard - ODBC client software so you'll have Postgres ODBC available on every - client platform we support (Win, Mac, Unix, VMS). - - We will probably be selling this product to people who need - commercial-quality support, but a freeware version will always be - available. Questions to postgres95@openlink.co.uk. - - 3.16) How do I use postgres for multi-dimensional indexing (> 2 - dimensions">)? - - - - Builtin R-Trees can handle polygons and boxes. In theory, R-trees can - be extended to handle higher number of dimensions. In practice, - extending R-trees require a bit of work and we don't currently have - any documentation on how to do it. - - 3.17) How do I do regular expression searches? case-insensitive regexp - searching? - - - - PostgreSQL supports the SQL LIKE syntax as well as more general - regular expression searching with the ~ operator. The !~ is the - negated regexp operator. ~* and !~* are the case-insensitive regular - expression operators. - - 3.18) I can't access the database as the 'root' user. - - - - You should not create database users with user id 0(root). They will - be unable to access the database. This is a security precaution - because of the ability of any user to dynamically link object modules - into the database engine. - - 3.19) I experienced a server crash during a vacuum. How do I remove the lock - file? - - - - If the server crashes during a vacuum command, chances are it will - leave a lock file hanging around. Attempts to re-run the vacuum - command result in +The fields in pg_group are: + * groname: the group name. This a char16 and should be purely + alphanumeric. Do not include underscores or other punctuation. + * grosysid: the group id. This is an int4. This should be unique for each + group. + * grolist: the list of pg_user id's that belong in the group. This is an + int4[]. + +3.10) What is the exact difference between binary cursors and normal +cursors? + +Normal cursors return data back in ASCII format. Since data is stored +natively in binary format, the system must do a conversion to produce the +ASCII format. In addition, ASCII formats are often large in size than binary +format. Once the attributes come back in ASCII, often the client application +then has to convert it to a binary format to manipulate it anyway. + +Binary cursors give you back the data in the native binary representation. +Thus, binary cursors will tend to be a little faster since there's less +overhead of conversion. + +However, ASCII is architectural neutral whereas binary representation can +differ between different machine architecture. Thus, if your client machine +uses a different representation than you server machine, getting back +attributes in binary format is probably not what you want. Also, if your +main purpose is displaying the data in ASCII, then getting it back in ASCII +will save you some effort on the client side. + +3.11) Why doesn't the != operator work? + +SQL specifies <> as the inequality operator, and that is what we have +defined for the built-in types. + +In 6.0, != is equivalent to <>. + +3.12) What is a R-tree index and what is it used for? + +An r-tree index is used for indexing spatial data. A hash index can't handle +range searches. A B-tree index only handles range searches in a single +dimension. R-tree's can handle multi-dimensional data. For example, if a +R-tree index can be built on an attribute of type 'point', the system can +more efficient answer queries like select all points within a bounding +rectangle. + +The canonical paper that describes the original R-Tree design is: + +Guttman, A. "R-Trees: A Dynamic Index Structure for Spatial Searching." Proc +of the 1984 ACM SIGMOD Int'l Conf on Mgmt of Data, 45-57. + +You can also find this paper in Stonebraker's "Readings in Database Systems" + +3.13) What is the maximum size for a tuple? + +Tuples are limited to 8K bytes. Taking into account system attributes and +other overhead, one should stay well shy of 8,000 bytes to be on the safe +side. To use attributes larger than 8K, try using the large objects +interface. + +Tuples do not cross 8k boundaries so a 5k tuple will require 8k of storage. + +3.14) I defined indices but my queries don't seem to make use of them. Why? + +PostgreSQL does not automatically maintain statistics. One has to make an +explicit 'vacuum' call to update the statistics. After statistics are +updated, the optimizer has a better shot at using indices. Note that the +optimizer is limited and does not use indices in some circumstances (such as +OR clauses). + +If the system still does not see the index, it is probably because you have +created an index on a field with the improper *_ops type. For example, you +have created a CHAR(4) field, but have specified a char_ops index +type_class. + +See the create_index manual page for information on what type classes are +available. It must match the field type. + +Postgres does not warn the user when the improper index is created. + +Indexes not used for ORDER BY operations. + +3.15) Are there ODBC drivers for PostgreSQL? + +There are two ODBC drivers available, PostODBC and OpenLink ODBC. + +For all people being interested in PostODBC, there are now two mailing lists +devoted to the discussion of PostODBC. The mailing lists are: + + * postodbc-users@listserv.direct. net + * postodbc-developers@listse rv.direct.net + +these lists are ordinary majordomo mailing lists. You can subscribe by +sending a mail to: + + * majordomo@listserv.direct.net + +OpenLink ODBC is currently in beta under Linux. You can get it from +http://www.openlinksw.com/postgres.html. It works with our standard ODBC +client software so you'll have Postgres ODBC available on every client +platform we support (Win, Mac, Unix, VMS). + +We will probably be selling this product to people who need +commercial-quality support, but a freeware version will always be available. +Questions to postgres95@openlink.co.uk. + +3.16) How do I use postgres for multi-dimensional indexing (> 2 +dimensions">)? + +Builtin R-Trees can handle polygons and boxes. In theory, R-trees can be +extended to handle higher number of dimensions. In practice, extending +R-trees require a bit of work and we don't currently have any documentation +on how to do it. + +3.17) How do I do regular expression searches? case-insensitive regexp +searching? + +PostgreSQL supports the SQL LIKE syntax as well as more general regular +expression searching with the ~ operator. The !~ is the negated regexp +operator. ~* and !~* are the case-insensitive regular expression operators. + +3.18) I can't access the database as the 'root' user. + +You should not create database users with user id 0(root). They will be +unable to access the database. This is a security precaution because of the +ability of any user to dynamically link object modules into the database +engine. + +3.19) I experienced a server crash during a vacuum. How do I remove the lock +file? + +If the server crashes during a vacuum command, chances are it will leave a +lock file hanging around. Attempts to re-run the vacuum command result in WARN:can't create lock file -- another vacuum cleaner running? - - - If you are sure that no vacuum is actually running, you can remove the - file called "pg_vlock" in your database directory (which is - $PGDATA/base/) - - 3.20) What is the difference between the various character types? +If you are sure that no vacuum is actually running, you can remove the file +called "pg_vlock" in your database directory (which is $PGDATA/base/) + +3.20) What is the difference between the various character types? Type Internal Name Notes -------------------------------------------------- @@ -734,48 +577,35 @@ VARCHAR(#) varchar size specifies maximum length, no padding TEXT text length limited only by maximum tuple length BYTEA bytea variable-length array of bytes - - - Remember, you need to use the internal name when creating indexes on - these fields or when doing other internal operations. - - The last four types above are "varlena" types (i.e. the first four - bytes is the length, followed by the data). CHAR(#) and VARCHAR(#) - allocate the maximum number of bytes no matter how much data is stored - in the field. TEXT and BYTEA are the only character types that have - variable length on the disk. - - 3.21) In a query, how do I detect if a field is NULL? - - - - PostgreSQL has two builtin keywords, "isnull" and "notnull" (note no - spaces). Version 1.05 and later and 6.* understand IS NULL and IS NOT - NULL. - - 3.22) How do I see how the query optimizer is evaluating my query? - - - - Place the word 'EXPLAIN' at the beginning of the query, for example: +Remember, you need to use the internal name when creating indexes on these +fields or when doing other internal operations. +The last four types above are "varlena" types (i.e. the first four bytes is +the length, followed by the data). CHAR(#) and VARCHAR(#) allocate the +maximum number of bytes no matter how much data is stored in the field. TEXT +and BYTEA are the only character types that have variable length on the +disk. + +3.21) In a query, how do I detect if a field is NULL? + +PostgreSQL has two builtin keywords, "isnull" and "notnull" (note no +spaces). Version 1.05 and later and 6.* understand IS NULL and IS NOT NULL. + +3.22) How do I see how the query optimizer is evaluating my query? + +Place the word 'EXPLAIN' at the beginning of the query, for example: EXPLAIN SELECT * FROM table1 WHERE age = 23; - - - 3.23) How do I create a serial field? - - - - Postgres does not allow the user to specifiy a user column as type - SERIAL. Instead, you can use each row's oid field as a unique value. - However, if you need to dump and reload the database, you need to be - using postgres version 1.07 or later or 6.* with pgdump's -o option or - COPY's WITH OIDS option to preserver the oids. - - Another valid way of doing this is to create a function: +3.23) How do I create a serial field? +Postgres does not allow the user to specifiy a user column as type SERIAL. +Instead, you can use each row's oid field as a unique value. However, if you +need to dump and reload the database, you need to be using postgres version +1.07 or later or 6.* with pgdump's -o option or COPY's WITH OIDS option to +preserver the oids. + +Another valid way of doing this is to create a function: create table my_oids (f1 int4); insert into my_oids values (1); @@ -783,358 +613,278 @@ BYTEA bytea variable-length array of bytes 'update my_oids set f1 = f1 + 1; select f1 from my_oids; ' language 'sql'; - - - then: - +then: create table my_stuff (my_key int4, value text); insert into my_stuff values (new_oid(), 'hello'); - - - However, keep in mind there is a race condition here where one server - could do the update, then another one do an update, and they both - could select the same new id. This statement should be performed - within a transaction. - - 3.24) How do I create a multi-column index? - - - - You can not directly create a multi-column index using create index. - You need to define a function which acts on the multiple columns, then - use create index with that function. - - 3.25) What are the temp_XXX files in my database directory? - - - - They are temp_ files generated by the query executor. For example, if - a sort needs to be done to satisfy an ORDER BY, some temp files are - generated as a result of the sort. - - If you have no transactions or sorts running at the time, it is safe - to delete the temp_ files. - - 3.26) Why are my table files not getting any smaller after a delete? - - - - If you run vacuum in pre-6.0, unused rows will be marked for reuse, - but the file blocks are not released. - - In 6.0, vacuum properly shrinks tables. - - 3.27) Why can't I connect to my database from another machine? - - - - The default configuration allows only connections from tcp/ip host - localhost. You need to add a host entry to the file pgsql/data/pg_hba. - - - 3.28) I get the error 'default index class unsupported' when creating an - index. How do I do it? - - - - You probably used: +However, keep in mind there is a race condition here where one server could +do the update, then another one do an update, and they both could select the +same new id. This statement should be performed within a transaction. +3.24) How do I create a multi-column index? + +You can not directly create a multi-column index using create index. You +need to define a function which acts on the multiple columns, then use +create index with that function. + +3.25) What are the temp_XXX files in my database directory? + +They are temp_ files generated by the query executor. For example, if a sort +needs to be done to satisfy an ORDER BY, some temp files are generated as a +result of the sort. + +If you have no transactions or sorts running at the time, it is safe to +delete the temp_ files. + +3.26) Why are my table files not getting any smaller after a delete? + +If you run vacuum in pre-6.0, unused rows will be marked for reuse, but the +file blocks are not released. + +In 6.0, vacuum properly shrinks tables. + +3.27) Why can't I connect to my database from another machine? + +The default configuration allows only connections from tcp/ip host +localhost. You need to add a host entry to the file pgsql/data/pg_hba. + +3.28) I get the error 'default index class unsupported' when creating an +index. How do I do it? + +You probably used: create index idx1 on person using btree (name); - - - PostgreSQL indexes are extensible, and therefore in pre-6.0, you must - specify a class_type when creating an index. Read the manual page for - create index (called create_index). - - Version 6.0, if you do not specify a class_type, it defaults to the - proper type for the column. - - 3.29) Why does creating an index crash the backend server? - - - - You have probably defined an incorrect *_ops type class for the field - you are indexing. - - 3.30) How do I specify a decimal constant as a float8, or a string as a text? - Why am I getting poor precision? - - - - Use the :: operator. It is needed only when the default promotion - rules fail. i.e.: +PostgreSQL indexes are extensible, and therefore in pre-6.0, you must +specify a class_type when creating an index. Read the manual page for create +index (called create_index). +Version 6.0, if you do not specify a class_type, it defaults to the proper +type for the column. + +3.29) Why does creating an index crash the backend server? + +You have probably defined an incorrect *_ops type class for the field you +are indexing. + +3.30) How do I specify a decimal constant as a float8, or a string as a +text? Why am I getting poor precision? + +Use the :: operator. It is needed only when the default promotion rules +fail. i.e.: insert into tab1 values (4.23::float8, '2343'::text) - - - The default floating-point constant is a float4 in releases prior to - 1.05. Later releases default to float8. - - 3.31) How do I find out what indexes or operations are defined in the - database? - - - - Run the file pgsql/src/tutorial/syscat.source. It illustrates many of - the 'select's needed to get information out of the database system - tables. - - 3.32) My database is corrupt. I can't do anything. What should I do? - - - - The 1.02 release has a README file and utility that describes a - possible cause of the problem and a workaround. - - This bug is fixed in 1.02.1. - - 3.33) Createdb, destroydb, createuser,destroyuser don't run. Why? - - - - Release 1.02 does not have this problem. - - The 1.01 release of PostgreSQL uses a variable called PAGER to filter - the output of SELECT statements. Unfortunately, this PAGER is used - even when the standard output is not a terminal. - - 3.34) Why does 'createuser' return 'unexpected last match in input(">)'? - - - - You have compile postgres with flex version 2.5.3. There is bug in - this version of flex. Use flex version 2.5.2 or flex 2.5.4 instead. - There is a doc/README.flex file which will properly patch the flex - 2.5.3 source code. - - 3.35) All my servers crash under concurrent table access. Why? - - - - This problem can be caused by a kernel that is not configured to - support semaphores. - - 3.36) What tools are available for hooking postgres to Web pages? - - - - For web integration, PHP/FI is an excellent interface. The URL for - that is http://www.vex.net/php/ - - PHP is great for simple stuff, but for more complex stuff, some still - use the perl interface and CGI.pm. - - An example of using WWW with C to talk to Postgres is can be tried at: - * http://postgreSQL.org/~mlc - - - - An WWW gatway based on WDB using perl can be downloaded from: - * http://www.eol.ists.ca/~dunlop/wdb -p95 - - 3.37) What is the time-warp feature and how does it relate to vacuum? - - - - PostgreSQL handles data changes differently than most database - systems. When a row is changed in a table, the original row is marked - with the time it was changed, and a new row is created with the - current data. By default, only current rows are used in a table. If - you specify a date/time after the table name in a FROM clause, you can - access the data that was current at that time, i.e. +The default floating-point constant is a float4 in releases prior to 1.05. +Later releases default to float8. +3.31) How do I find out what indexes or operations are defined in the +database? + +Run the file pgsql/src/tutorial/syscat.source. It illustrates many of the +'select's needed to get information out of the database system tables. + +3.32) My database is corrupt. I can't do anything. What should I do? + +The 1.02 release has a README file and utility that describes a possible +cause of the problem and a workaround. + +This bug is fixed in 1.02.1. + +3.33) Createdb, destroydb, createuser,destroyuser don't run. Why? + +Release 1.02 does not have this problem. + +The 1.01 release of PostgreSQL uses a variable called PAGER to filter the +output of SELECT statements. Unfortunately, this PAGER is used even when the +standard output is not a terminal. + +3.34) Why does 'createuser' return 'unexpected last match in input(">)'? + +You have compile postgres with flex version 2.5.3. There is bug in this +version of flex. Use flex version 2.5.2 or flex 2.5.4 instead. There is a +doc/README.flex file which will properly patch the flex 2.5.3 source code. + +3.35) All my servers crash under concurrent table access. Why? + +This problem can be caused by a kernel that is not configured to support +semaphores. + +3.36) What tools are available for hooking postgres to Web pages? + +For web integration, PHP/FI is an excellent interface. The URL for that is +http://www.vex.net/php/ + +PHP is great for simple stuff, but for more complex stuff, some still use +the perl interface and CGI.pm. + +An example of using WWW with C to talk to Postgres is can be tried at: + + * http://postgreSQL.org/~mlc + +An WWW gatway based on WDB using perl can be downloaded from: + + * http://www.eol.ists.ca/~dunlop/wdb -p95 + +3.37) What is the time-warp feature and how does it relate to vacuum? + +PostgreSQL handles data changes differently than most database systems. When +a row is changed in a table, the original row is marked with the time it was +changed, and a new row is created with the current data. By default, only +current rows are used in a table. If you specify a date/time after the table +name in a FROM clause, you can access the data that was current at that +time, i.e. SELECT * FROM employees ['July 24, 1996 09:00:00'] - - - displays employee rows in the table at the specified time. You can - specify intervals like [date,date], [date,], [,date], or [,]. This - last option accesses all rows that ever existed. - - INSERTed rows get a timestamp too, so rows that were not in the table - at the desired time will not appear. - - Vacuum removes rows that are no longer current. This time-warp feature - is used by the engine for rollback and crash recovery. Expiration - times can be set with purge. - - In 6.0, once a table is vacuumed, the creation time of a row may be - incorrect, causing time-traval to fail. - - The time-travel feature will be removed in 7.0. - - 3.38) How do I tune the database engine for better performance? - - - - There are two things that can be done. You can use Openlink's option - to disable fsync() by starting the postmaster with a '-o -F' option. - This will prevent fsync()'s from flushing to disk after every - transaction. - - You can also use the postmaster -B option to increase the number of - shared memory buffers shared among the backend processes. If you make - this parameter too high, the process will not start or crash - unexpectedly. Each buffer is 8K and the defualt is 64 buffers. - - 3.39) What debugging features are available in PostgreSQL? - - - - PostgreSQL has several features that report status information that - can be valuable for debugging purposes. - - First, by compiling with DEBUG defined, many assert()'s monitor the - progress of the backend and halt the program when something unexpected - occurs. - - Both postmaster and postgres have several debug options available. - First, whenever you start the postmaster, make sure you send the - standard output and error to a log file, like: +displays employee rows in the table at the specified time. You can specify +intervals like [date,date], [date,], [,date], or [,]. This last option +accesses all rows that ever existed. +INSERTed rows get a timestamp too, so rows that were not in the table at the +desired time will not appear. + +Vacuum removes rows that are no longer current. This time-warp feature is +used by the engine for rollback and crash recovery. Expiration times can be +set with purge. + +In 6.0, once a table is vacuumed, the creation time of a row may be +incorrect, causing time-traval to fail. + +The time-travel feature will be removed in 7.0. + +3.38) How do I tune the database engine for better performance? + +There are two things that can be done. You can use Openlink's option to +disable fsync() by starting the postmaster with a '-o -F' option. This will +prevent fsync()'s from flushing to disk after every transaction. + +You can also use the postmaster -B option to increase the number of shared +memory buffers shared among the backend processes. If you make this +parameter too high, the process will not start or crash unexpectedly. Each +buffer is 8K and the defualt is 64 buffers. + +3.39) What debugging features are available in PostgreSQL? + +PostgreSQL has several features that report status information that can be +valuable for debugging purposes. + +First, by compiling with DEBUG defined, many assert()'s monitor the progress +of the backend and halt the program when something unexpected occurs. + +Both postmaster and postgres have several debug options available. First, +whenever you start the postmaster, make sure you send the standard output +and error to a log file, like: cd /usr/local/pgsql ./bin/postmaster >server.log 2>&1 & - - - This will put a server.log file in the top-level PostgreSQL directory. - This file can contain useful information about problems or errors - encountered by the server. Postmaster has a -d option that allows even - more detailed information to be reported. The -d option takes a number - 1-3 that specifies the debug level. The query plans in a verbose debug - file can be formatted using the 'indent' program. (You may need to - remove the '====' lines in 1.* releases.) Be warned that a debug level - greater than one generates large log files in 1.* releases. - - You can actuall run the postgres backend from the command line, and - type your SQL statement directly. This is recommended ONLY for - debugging purposes. Note that a newline terminates the query, not a - semicolon. If you have compiled with debugging symbols, you can - perhaps use a debugger to see what is happening. Because the backend - was not started from the postmaster, it is not running in an identical - environment and locking/backend interaction problems may not be - duplicated. Some operating system can attach to a running backend - directly to diagnose problems. - - The postgres program has a -s, -A, -t options that can be very usefull - for debugging and performance measurements. - - The EXPLAIN command (see this FAQ) allows you to see how PostgreSQL is - iterpreting your query. - - 3.40) What is an oid? What is a tid? - - - - Oids are Postgres's answer to unique row ids or serial columns. Every - row that is created in Postgres gets a unique oid. All oids generated - by initdb are less than 16384 (from backend/access/transam.h). All - post-initdb (user-created) oids are equal or greater that this. All - these oids are unique not only within a table, or database, but unique - within the entire postgres installation. - - Postgres uses oids in its internal system tables to link rows in - separate tables. These oids can be used to identify specific user rows - and used in joins. It is recommended you use column type oid to store - oid values. See the sql(l) manual page to see the other internal - columns. - - Tids are used to indentify specific physical rows with block and - offset values. Tids change after rows are modified or reloaded. They - are used by index entries to point to physical rows. They can not be - accessed through sql. - - 3.41) What is the meaning of some of the terms used in Postgres? - - - - Some of the source code and older documentation use terms that have - more common usage. Here are some: - * row, record, tuple - * attribute, field, column - * table, class - * retrieve, select - * replace, update - * append, insert - * oid, serial value - * portal, cursor - * range variable, table name, table alias - - - - Please let me know if you think of any more. - - - _________________________________________________________________ - -Section 4: Extending PostgreSQL +This will put a server.log file in the top-level PostgreSQL directory. This +file can contain useful information about problems or errors encountered by +the server. Postmaster has a -d option that allows even more detailed +information to be reported. The -d option takes a number 1-3 that specifies +the debug level. The query plans in a verbose debug file can be formatted +using the 'indent' program. (You may need to remove the '====' lines in 1.* +releases.) Be warned that a debug level greater than one generates large log +files in 1.* releases. - - - 4.1) I wrote a user-defined function and when I run it in psql, it dumps - core. - - - - The problem could be a number of things. Try testing your user-defined - function in a stand alone test program first. Also, make sure you are - not sending elog NOTICES when the front-end is expecting data, such as - during a type_in() or type_out() functions - - 4.2) I get messages of the type NOTICE:PortalHeapMemoryFree: 0x402251d0 not - in alloc set! - - - - You are pfree'ing something that was not palloc'ed. When writing - user-defined functions, do not include the file "libpq-fe.h". Doing so - will cause your palloc to be a malloc instead of a free. Then, when - the backend pfrees the storage, you get the notice message. - - 4.3) I've written some nifty new types and functions for PostgreSQL. - - - - Please share them with other PostgreSQL users. Send your extensions to - mailing list, and they will eventually end up in the contrib/ - subdirectory. - - 4.4) How do I write a C function to return a tuple? - - - - This requires extreme wizardry, so extreme that the authors have not - ever tried it, though in principle it can be done. The short answer is - ... you can't. This capability is forthcoming in the future. - - - _________________________________________________________________ - -Section 5: Bugs +You can actuall run the postgres backend from the command line, and type +your SQL statement directly. This is recommended ONLY for debugging +purposes. Note that a newline terminates the query, not a semicolon. If you +have compiled with debugging symbols, you can perhaps use a debugger to see +what is happening. Because the backend was not started from the postmaster, +it is not running in an identical environment and locking/backend +interaction problems may not be duplicated. Some operating system can attach +to a running backend directly to diagnose problems. - - - 5.1) How do I make a bug report? - - - - Check the current FAQ at http://postgreSQL.org - - Also check out our ftp site ftp://ftp.postgreSQL.org/pub to see if - there is a more recent PostgreSQL version. - - You can also fill out the "bug-template" file and send it to: - * hackers@postgreSQL.org - - - - This is the address of the developers mailing list. +The postgres program has a -s, -A, -t options that can be very usefull for +debugging and performance measurements. + +The EXPLAIN command (see this FAQ) allows you to see how PostgreSQL is +iterpreting your query. + +3.40) What is an oid? What is a tid? + +Oids are Postgres's answer to unique row ids or serial columns. Every row +that is created in Postgres gets a unique oid. All oids generated by initdb +are less than 16384 (from backend/access/transam.h). All post-initdb +(user-created) oids are equal or greater that this. All these oids are +unique not only within a table, or database, but unique within the entire +postgres installation. + +Postgres uses oids in its internal system tables to link rows in separate +tables. These oids can be used to identify specific user rows and used in +joins. It is recommended you use column type oid to store oid values. See +the sql(l) manual page to see the other internal columns. + +Tids are used to indentify specific physical rows with block and offset +values. Tids change after rows are modified or reloaded. They are used by +index entries to point to physical rows. They can not be accessed through +sql. + +3.41) What is the meaning of some of the terms used in Postgres? + +Some of the source code and older documentation use terms that have more +common usage. Here are some: + + * row, record, tuple + * attribute, field, column + * table, class + * retrieve, select + * replace, update + * append, insert + * oid, serial value + * portal, cursor + * range variable, table name, table alias + +Please let me know if you think of any more. + +---------------------------------------------------------------------------- + +Section 4: Extending PostgreSQL + +4.1) I wrote a user-defined function and when I run it in psql, it dumps +core. + +The problem could be a number of things. Try testing your user-defined +function in a stand alone test program first. Also, make sure you are not +sending elog NOTICES when the front-end is expecting data, such as during a +type_in() or type_out() functions + +4.2) I get messages of the type NOTICE:PortalHeapMemoryFree: 0x402251d0 not +in alloc set! + +You are pfree'ing something that was not palloc'ed. When writing +user-defined functions, do not include the file "libpq-fe.h". Doing so will +cause your palloc to be a malloc instead of a free. Then, when the backend +pfrees the storage, you get the notice message. + +4.3) I've written some nifty new types and functions for PostgreSQL. + +Please share them with other PostgreSQL users. Send your extensions to +mailing list, and they will eventually end up in the contrib/ subdirectory. + +4.4) How do I write a C function to return a tuple? + +This requires extreme wizardry, so extreme that the authors have not ever +tried it, though in principle it can be done. The short answer is ... you +can't. This capability is forthcoming in the future. + +---------------------------------------------------------------------------- + +Section 5: Bugs + +5.1) How do I make a bug report? + +Check the current FAQ at http://postgreSQL.org + +Also check out our ftp site ftp://ftp.postgreSQL.org/pub to see if there is +a more recent PostgreSQL version. + +You can also fill out the "bug-template" file and send it to: + + * bugs@postgreSQL.org + +This is the address of the developers mailing list. diff --git a/doc/TODO b/doc/TODO index ffea200f5c..132e59f613 100644 --- a/doc/TODO +++ b/doc/TODO @@ -1,7 +1,7 @@ ==================================================== TODO list (FAQ) for PostgreSQL ==================================================== -last updated: Thu Jan 2 11:19:41 EST 1997 +last updated: Wed Jan 29 00:16:44 EST 1997 current maintainer: Bruce Momjian (maillist@candle.pha.pa.us) @@ -41,6 +41,9 @@ SELECT on two tables where zero or one table in WHERE and target fix system to use oid index using constant without cast to oid COUNT on VIEW always returns zero (maybe because there is no oid for views?) CREATE VIEW requires super-user priviledge +SELECT a[1] FROM test fails, it needs test.a[1] +INSERT INTO ... SELECT DISTINCT ... generates error on DISTINCT +pg_database.datdba is oid, should be int4 ENHANCEMENTS ------------ @@ -48,9 +51,10 @@ Add full ANSI SQL capabilities add subselects, possibility using temporary SQL functions Implement HAVING clause Implement EXISTS qualifier - column constraints (using rules), esp. primary keys + column constraints (using rules), PRIMARY KEY during table creation add DEFAULT, RESTRAINT, and CHECK capabilities report "Not implemented" if valid syntax is supplied + add NOT NULL to CREATE statement add OUTER joins, left and right make VIEWs updateable where possible add UNIONS, INTERSECTS, SUBTRACTS @@ -117,6 +121,8 @@ Add upper/lower functions -Add table/column/function discription table indexed by oid -make all identifiers case-insensitive(Bruce) add pg_type attribute to identify types that need length (bpchar, varchar) +add UNIQUE capability to non-btree indexes +improve auto-type casting PERFORMANCE ----------- @@ -211,6 +217,7 @@ Allow restriction on who can do backend COPY(Bryan) Can shrink tables, pg_time and pg_log(Vadim & Erich) Change debug level 2 to print queries only, changed debug heading layout(Bruce) Change default decimal constant representation from float4 to float8(Bruce) +European date format now set when postmaster is started Execute lowercase function names if not found with exact case Fixes for aggregate/GROUP processing, allow 'select sum(func(x),sum(x+y) from z' Gist now included in the distrubution(Marc) @@ -222,7 +229,7 @@ Libpq++ improvements New options to initdb(Bryan) Pg_dump allow dump of oid's(Bruce) Pg_dump create indexes after tables are loaded for speed(Bruce) -Pg_dump(Bruce) +Pg_dumpall dumps all databases, and the user table Pginterface additions for NULL values(Bruce) Prevent postmaster from being run as root Psql \h and \? is now readable(Bruce) @@ -237,6 +244,7 @@ Remove compile-time parameters to enable binary distributions(Bryan) Reverse meaning of HBA masks(Bryan) Secure Authentication of local users(Bryan) Speed up vacuum(Vadim) +Vacuum now had VERBOSE option(Bruce) Source tree changes -------------------