Commit Graph

15473 Commits

Author SHA1 Message Date
Tom Lane f33a178a34 Doc: improve and centralize the documentation for OID alias types.
Previously, a lot of information about type regclass existed only
in the discussion of the sequence functions.  Maybe that made sense
in the beginning, because I think originally those were the only
functions taking regclass.  But it doesn't make sense anymore.
Move that material to the "Object Identifier Types" section in
datatype.sgml, generalize it to talk about the other reg* types
as well, and add more examples.

Per bug #16991 from Federico Caselli.

Discussion: https://postgr.es/m/16991-bcaeaafa17e0a723@postgresql.org
2021-05-05 11:26:48 -04:00
Peter Eisentraut c98a6d7887 doc: Fix typos 2021-05-04 15:45:13 +02:00
Alexander Korotkov ae9492a61b Remove mention of the version number from pg_trgm docs
We don't usually mention the version number in similar situations.  So, neither
mention it here.

Reported-by: Bruce Momjian
Discussion: https://postgr.es/m/20210503234914.GO6180%40momjian.us
2021-05-04 03:59:21 +03:00
Peter Eisentraut 5df6aeab42 doc: Add index entry for "multirange type"
Before now, looking up "multirange" in the index only led to the
multirange() function.  To make this more useful, also add an entry
pointing to the range types section.
2021-05-03 20:14:03 +02:00
Tom Lane e6f9539dc3 Doc: add an example of a self-referential foreign key to ddl.sgml.
While we've always allowed such cases, the documentation didn't
say you could do it.

Discussion: https://postgr.es/m/161969805833.690.13680986983883602407@wrigleys.postgresql.org
2021-04-30 15:37:56 -04:00
Tom Lane 386e64ea5a Doc: update libpq's documentation for PQfn().
Mention specifically that you can't call aggregates, window functions,
or procedures this way (the inability to call SRFs was already
mentioned).

Also, the claim that PQfn doesn't support NULL arguments or results
has been a lie since we invented protocol 3.0.  Not sure why this
text was never updated for that, but do it now.

Discussion: https://postgr.es/m/2039442.1615317309@sss.pgh.pa.us
2021-04-30 15:10:06 -04:00
Alvaro Herrera 94b9cb7225
Improve documentation for default_tablespace on partitioned tables
Backpatch to 12, where 87259588d0 introduced the current behavior.

Per note from Justin Pryzby.

Co-authored-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210416143135.GI3315@telsasoft.com
2021-04-29 11:31:24 -04:00
Michael Paquier 2977f244bc doc: Fix description of target_session_attrs=prefer-standby
If no standbys can be found in the set of connection points provided,
the fallback behavior is "any", and not "all" that does not exist.

Author: Greg Nancarrow
Reviewed-by: Laurenz Albe
Discussion: https://postgr.es/m/CAJcOf-fDaCv8qCpWH7k5Yh6zFxZeUwZowu4sCWQ2zFx4CdkHpA@mail.gmail.com
2021-04-29 11:44:24 +09:00
Alvaro Herrera d6b8d29419
Allow a partdesc-omitting-partitions to be cached
Makes partition descriptor acquisition faster during the transient
period in which a partition is in the process of being detached.

This also adds the restriction that only one partition can be in
pending-detach state for a partitioned table.

While at it, return find_inheritance_children() API to what it was
before 71f4c8c6f7, and create a separate
find_inheritance_children_extended() that returns detailed info about
detached partitions.

(This incidentally fixes a bug in 8aba932251 whereby a memory context
holding a transient partdesc is reparented to a NULL PortalContext,
leading to permanent leak of that memory.  The fix is to no longer rely
on reparenting contexts to PortalContext.   Reported by Amit Langote.)

Per gripe from Amit Langote
Discussion: https://postgr.es/m/CA+HiwqFgpP1LxJZOBYGt9rpvTjXXkg5qG2+Xch2Z1Q7KrqZR1A@mail.gmail.com
2021-04-28 15:44:35 -04:00
Tom Lane c93f8f3b8d Doc: fix discussion of how to get real Julian Dates.
Somehow I'd convinced myself that rotating to UTC-12 was the way
to do this, but upon further review, it's definitely UTC+12.

Discussion: https://postgr.es/m/1197050.1619123213@sss.pgh.pa.us
2021-04-28 10:03:28 -04:00
Fujii Masao 0c8f40863a doc: Review for "Allow TRUNCATE command to truncate foreign tables".
Typos, corrections and language improvements in the docs.

Author: Justin Pryzby, Fujii Masao
Reviewed-by: Bharath Rupireddy, Justin Pryzby, Fujii Masao
Discussion: https://postgr.es/m/20210411041658.GB14564@telsasoft.com
2021-04-27 18:39:30 +09:00
Fujii Masao 8e9ea08bae Don't pass "ONLY" options specified in TRUNCATE to foreign data wrapper.
Commit 8ff1c94649 allowed TRUNCATE command to truncate foreign tables.
Previously the information about "ONLY" options specified in TRUNCATE
command were passed to the foreign data wrapper. Then postgres_fdw
constructed the TRUNCATE command to issue the remote server and
included "ONLY" options in it based on the passed information.

On the other hand, "ONLY" options specified in SELECT, UPDATE or DELETE
have no effect when accessing or modifying the remote table, i.e.,
are not passed to the foreign data wrapper. So it's inconsistent to
make only TRUNCATE command pass the "ONLY" options to the foreign data
wrapper. Therefore this commit changes the TRUNCATE command so that
it doesn't pass the "ONLY" options to the foreign data wrapper,
for the consistency with other statements. Also this commit changes
postgres_fdw so that it always doesn't include "ONLY" options in
the TRUNCATE command that it constructs.

Author: Fujii Masao
Reviewed-by: Bharath Rupireddy, Kyotaro Horiguchi, Justin Pryzby, Zhihong Yu
Discussion: https://postgr.es/m/551ed8c1-f531-818b-664a-2cecdab99cd8@oss.nttdata.com
2021-04-27 14:41:27 +09:00
Tom Lane 79a5928ebc Doc: document EXTRACT(JULIAN ...), improve Julian Date explanation.
For some reason, the "julian" option for extract()/date_part() has
never gotten listed in the manual.  Also, while Appendix B mentioned
in passing that we don't conform to the usual astronomical definition
that a Julian date starts at noon UTC, it was kind of vague about what
we do instead.  Clarify that, and add an example showing how to get
the astronomical definition if you want it.

It's been like this for ages, so back-patch to all supported branches.

Discussion: https://postgr.es/m/1197050.1619123213@sss.pgh.pa.us
2021-04-26 11:50:35 -04:00
Andrew Dunstan b859d94c63 Provide pg_amcheck with an --install-missing option
This will install amcheck in the database if not present. The default
schema is for the extension is pg_catalog, but this can be overridden by
providing a value for the option.

Mark Dilger, slightly editorialized by me.

(rather divergent)
Discussion: https://postgr.es/m/bdc0f7c2-09e3-ee57-8471-569dfb509234@dunslane.net
2021-04-24 10:13:07 -04:00
Michael Paquier 0d0049c58b Doc: Remove extraneous whitespaces with some tags
Author: Justin Pryzby
Discussion: https://postgr.es/m/20210423184338.GL7256@telsasoft.com
2021-04-24 10:44:13 +09:00
Magnus Hagander 7531fcb1fc Mention that toplevel is part of pg_stat_statements key.
While at it, also document that toplevel is always true if
pg_stat_statements.track is set to top.

Author: Julien Rouhaud
Reported-By: Fujii Masao
Discussion: https://postgr.es/m/a878d5ea-64a7-485e-5d2f-177618ebc52d@oss.nttdata.com
2021-04-23 11:45:28 +02:00
Peter Eisentraut 9bd563aa9f doc: Fix typos
Author: Justin Pryzby <pryzby@telsasoft.com>
2021-04-23 09:28:44 +02:00
Fujii Masao eaec48b3c5 doc: Fix obsolete description about pg_basebackup.
Previously it was documented that if using "-X none" option there was
no guarantee that all required WAL files were archived at the end of
pg_basebackup when taking a backup from the standby. But this limitation
was removed by commit 52f8a59dd9. Now, even when taking a backup
from the standby, pg_basebackup can wait for all required WAL files
to be archived. Therefore this commit removes such obsolete
description from the docs.

Also this commit adds new description about the limitation when
taking a backup from the standby, into the docs. The limitation is that
pg_basebackup cannot force the standbfy to switch to a new WAL file
at the end of backup, which may cause pg_basebackup to wait a long
time for the last required WAL file to be switched and archived,
especially when write activity on the primary is low.

Back-patch to v10 where the issue was introduced.

Reported-by: Kyotaro Horiguchi
Author: Kyotaro Horiguchi, Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/20210420.133235.1342729068750553399.horikyota.ntt@gmail.com
2021-04-23 15:45:46 +09:00
Peter Eisentraut 197d33ccbe Fix some trailing whitespace in documentation files 2021-04-22 22:47:57 +02:00
Bruce Momjian 84f15ccd4c doc: mention <link> can be inside of <command>, but not <xref>
This was discussed in commit 9081bddbd.

Reported-by: Peter Eisentraut

Discussion: https://postgr.es/m/flat/87o8pco34z.fsf@wibble.ilmari.org
2021-04-22 16:01:17 -04:00
Tom Lane 82b13dbc4d Doc: document the tie-breaking behavior of the round() function.
Back-patch to v13; the table layout in older branches is unfriendly
to adding such details.

Laurenz Albe

Discussion: https://postgr.es/m/161881920775.685.12293798764864559341@wrigleys.postgresql.org
2021-04-22 14:47:26 -04:00
Michael Paquier 1599e7b375 doc: Move parallel_leader_participation to its correct category
parallel_leader_participation got introduced in e5253fd, where it was
listed under RESOURCES_ASYNCHRONOUS in guc.c, but the documentation
did not reflect that and listed it with the other planner-related
options.  This commit fixes this inconsistency as the parameter is
intended to be an asynchronous one.

While on it, reorganize a bit the section dedicated to asynchronous
parameters, backend_flush_after being moved first to do better in terms
of alphabetical order of the options listed.

Reported-by: Yanliang Lei
Author: Bharath Rupireddy
Discussion: https://postgr.es/m/16972-42d4b0c15aa1d5f5@postgresql.org
2021-04-22 09:47:43 +09:00
Peter Eisentraut 544b28088f doc: Improve hyphenation consistency 2021-04-21 08:14:43 +02:00
Michael Paquier 64087eb5de doc: List compute_query_id in required config for pg_stat_statements
Not enabling compute_query_id would disable pg_stat_statements even if
the module is listed in shared_preload_libraries, so add it to the
minimum configuration set as listed in its documentation.

Author: Greg Nancarrow
Reviewed-by: Julien Rouhaud, Bharath Rupireddy
Discussion: https://postgr.es/m/CAJcOf-fXyb2QiDbwftD813UF70w-+BsK-03bFp1GrijXU9GQYQ@mail.gmail.com
2021-04-21 12:02:41 +09:00
Bruce Momjian db01f797dd Fix interaction of log_line_prefix's query_id and log_statement
log_statement is issued before query_id can be computed, so properly
clear the value, and document the interaction.

Reported-by: Fujii Masao, Michael Paquier

Discussion: https://postgr.es/m/YHPkU8hFi4no4NSw@paquier.xyz

Author: Julien Rouhaud
2021-04-20 12:57:59 -04:00
Bruce Momjian 9660834dd8 adjust query id feature to use pg_stat_activity.query_id
Previously, it was pg_stat_activity.queryid to match the
pg_stat_statements queryid column.  This is an adjustment to patch
4f0b0966c8.  This also adjusts some of the internal function calls to
match.  Catversion bumped.

Reported-by: Álvaro Herrera, Julien Rouhaud

Discussion: https://postgr.es/m/20210408032704.GA7498@alvherre.pgsql
2021-04-20 12:22:26 -04:00
Amit Kapila c64dcc7fee Fix test case added by commit f5fc2f5b23.
In the new test after resetting the stats, we were not waiting for the
stats message to be delivered. Also, we need to decode the results for
the new test, otherwise, it will show the old stats.

In passing,
a. Change docs added by commit f5fc2f5b23 as per suggestion by
Justin Pryzby.
b. Bump the PGSTAT_FILE_FORMAT_ID as commit f5fc2f5b23 changes the file
format of stats.

Reported-by: Tom Lane based on buildfarm reports
Author: Vignesh C, Justin Pryzby
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
2021-04-19 09:02:47 +05:30
Michael Paquier 7ef8b52cf0 Fix typos and grammar in comments and docs
Author: Justin Pryzby
Discussion: https://postgr.es/m/20210416070310.GG3315@telsasoft.com
2021-04-19 11:32:30 +09:00
Peter Eisentraut f7c09706c1 doc: Fix up spacing around verbatim DocBook elements 2021-04-17 14:14:26 +02:00
Michael Paquier 254a2164e5 doc: Fix typo in example query of SQL/JSON
Author: Erik Rijkers
Discussion: https://postgr.es/m/1219476687.20432.1617452918468@webmailclassic.xs4all.nl
Backpatch-through: 12
2021-04-16 16:56:12 +09:00
Amit Kapila f5fc2f5b23 Add information of total data processed to replication slot stats.
This adds the statistics about total transactions count and total
transaction data logically sent to the decoding output plugin from
ReorderBuffer. Users can query the pg_stat_replication_slots view to check
these stats.

Suggested-by: Andres Freund
Author: Vignesh C and Amit Kapila
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
2021-04-16 07:34:43 +05:30
Thomas Munro 1bf946bd43 Doc: Document known problem with Windows collation versions.
Warn users that locales with traditional Windows NLS names like
"English_United States.1252" won't provide version information, and that
something like initdb --lc-collate=en-US would be needed to fix that
problem for the initial template databases.

Discussion: https://postgr.es/m/CA%2BhUKGJ_hk3rU%3D%3Dg2FpAMChb_4i%2BTJacpjjqFsinY-tRM3FBmA%40mail.gmail.com
2021-04-16 13:23:47 +12:00
Tom Lane 1111b2668d Undo decision to allow pg_proc.prosrc to be NULL.
Commit e717a9a18 changed the longstanding rule that prosrc is NOT NULL
because when a SQL-language function is written in SQL-standard style,
we don't currently have anything useful to put there.  This seems a poor
decision though, as it could easily have negative impacts on external
PLs (opening them to crashes they didn't use to have, for instance).
SQL-function-related code can just as easily test "is prosqlbody not
null" as "is prosrc null", so there's no real gain there either.
Hence, revert the NOT NULL marking removal and adjust related logic.

For now, we just put an empty string into prosrc for SQL-standard
functions.  Maybe we'll have a better idea later, although the
history of things like pg_attrdef.adsrc suggests that it's not
easy to maintain a string equivalent of a node tree.

This also adds an assertion that queryDesc->sourceText != NULL
to standard_ExecutorStart.  We'd been silently relying on that
for awhile, so let's make it less silent.

Also fix some overlooked documentation and test cases.

Discussion: https://postgr.es/m/2197698.1617984583@sss.pgh.pa.us
2021-04-15 17:17:20 -04:00
Peter Eisentraut fae65629ce Revert "psql: Show all query results by default"
This reverts commit 3a51306722.

Per discussion, this patch had too many issues to resolve at this
point of the development cycle.  We'll try again in the future.

Discussion: https://www.postgresql.org/message-id/flat/alpine.DEB.2.21.1904132231510.8961@lancre
2021-04-15 19:42:55 +02:00
Fujii Masao e2e2efca85 doc: Add missing COMPRESSION into CREATE TABLE synopsis.
Commit bbe0a81db6 introduced "INCLUDING COMPRESSION" option
in CREATE TABLE command, but forgot to mention it in the
CREATE TABLE syntax synopsis.

Author: Fujii Masao
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/54d30e66-dbd6-5485-aaf6-a291ed55919d@oss.nttdata.com
2021-04-15 23:15:19 +09:00
Michael Paquier 1840d9f4c8 doc: Simplify example of HISTFILE for psql
e4c7619 has added a space to the example used for HISTFILE in the docs
of psql before the variable DBNAME, as a workaround because variables
were not parsed the same way back then.  This behavior has changed in
9.2, causing the example in the psql docs to result in the same history
file created with or without a space added before the DBNAME variable.

Let's just remove this space in the example, to reduce any confusion, as
the point of it is to prove that a per-database history file is easy to
set up, and that's easier to read this way.

Per discussion with Tom Lane.

Reported-by: Ludovic Kuty
Discussion: https://postgr.es/m/161830067409.691.16198363670687811485@wrigleys.postgresql.org
2021-04-15 16:45:34 +09:00
Michael Paquier 344487e2db Tweak behavior of pg_dump --extension with configuration tables
6568cef, that introduced the option, had an inconsistent behavior when
it comes to configuration tables set up by pg_extension_config_dump, as
the data of all configuration tables would included in a dump even for
extensions not listed by a set of --extension switches.

The contents dumped changed depending on the schema where an extension
was installed when an extension was not listed.  For example, an
extension installed under the public schema would have its configuration
data not dumped even when not listed with --extension, which was
inconsistent with the case of an extension installed on a non-public
schema, where the configuration would be dumped.

Per discussion with Noah, we have settled down to the simple rule of
dumping configuration data of an extension if it is listed in
--extension (default is unchanged and backward-compatible, to dump
everything on sight if there are no extensions directly listed).  This
avoids some weird cases where the dumps depended on a --schema for one.

More tests are added to cover the gap, where we cross-check more
behaviors depending on --schema when an extension is not listed.

Reported-by: Noah Misch
Reviewed-by: Noah Misch
Discussion: https://postgr.es/m/20210404220802.GA728316@rfd.leadboat.com
2021-04-15 10:03:46 +09:00
Michael Paquier ac725ee0f9 doc: Move force_parallel_mode to section for developer options
This GUC has always been classified as a planner option since its
introduction in 7c944bd, and was listed in postgresql.conf.sample.  As
this parameter exists for testing purposes, move it to the section
dedicated to developer parameters and hence remove it from
postgresql.conf.sample.  This will avoid any temptation to play with it
on production servers for users that should never really have to touch
this parameter.

The general description used for developer options is reworded a bit, to
take into account the inclusion of force_parallel_mode, per a suggestion
from Tom Lane.

Per discussion between Tom Lane, Bruce Momjian, Justin Pryzby, Bharath
Rupireddy and me.

Author: Justin Pryzby, Tom Lane
Discussion: https://postgr.es/m/20210403152402.GA8049@momjian.us
2021-04-14 15:55:55 +09:00
Robert Haas e8c435a824 docs: Update TOAST storage docs for configurable compression.
Mention that there are multiple TOAST compression methods and that the
compression method used is stored in a TOAST pointer along with the
other information that was stored there previously. Add a reference to
the documentation for default_toast_compression, where the supported
methods are listed, instead of duplicating that here.

I haven't tried to preserve the text claiming that pglz is "fairly
simple and very fast." I have no view on the veracity of the former
claim, but LZ4 seems to be faster (and to compress better) so it
seems better not to muddy the waters by talking about compression
speed as a strong point of PGLZ.

Patch by me, reviewed by Justin Pryzby.

Discussion: http://postgr.es/m/CA+Tgmoaw_YBwQhOS_hhEPPwFhfAnu+VCLs18EfGr9gQw1z4H-w@mail.gmail.com
2021-04-13 15:13:26 -04:00
Fujii Masao 5fe83adad9 doc: Fix typo in logicaldecoding.sgml.
Introduced in commit 0aa8a01d04.

Author: Peter Smith
Discussion: https://postgr.es/m/CAHut+Ps8rkVHKWyjg09Fb1PaVG5-EhoFTFJ9OZMF4HPzDSXfew@mail.gmail.com
2021-04-13 14:21:51 +09:00
Michael Paquier b094063cd1 Move log_autovacuum_min_duration into its correct sections
This GUC has already been classified as LOGGING_WHAT, but its location
in postgresql.conf.sample and the documentation did not reflect that, so
fix those inconsistencies.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20210404012546.GK6592@telsasoft.com
2021-04-12 13:53:17 +09:00
Amit Kapila 15c1a9d9cb doc: Update information of new messages for logical replication.
Updated documentation for new messages added for streaming of in-progress
transactions, as well as changes made to the existing messages. It also
updates the information of protocol versions supported for logical
replication.

Author: Ajin Cherian
Reviewed-by: Amit Kapila, Peter Smith, Euler Taveira
Discussion: https://postgr.es/m/CAFPTHDYHN9m=MZZct-B=BYg_TETvv+kXvL9RD2DpaBS5pGxGYg@mail.gmail.com
2021-04-12 09:27:10 +05:30
Tom Lane 07b76833b1 Doc: update documentation of check_function_bodies.
Adjust docs and description string to note that check_function_bodies
applies to procedures too.  (In hindsight it should have been named
check_routine_bodies, but it seems too late for that now.)

Daniel Westermann

Discussion: https://postgr.es/m/GV0P278MB04834A9EB9A74B036DC7CE49D2739@GV0P278MB0483.CHEP278.PROD.OUTLOOK.COM
2021-04-10 12:08:28 -04:00
Peter Eisentraut 9cae39b8e6 doc: Fix man page whitespace issues
Whitespace between tags is significant, and in some cases it creates
extra vertical space in man pages.  The fix is to remove some newlines
in the markup.
2021-04-09 23:36:46 +02:00
Thomas Munro dc88460c24 Doc: Review for "Optionally prefetch referenced data in recovery."
Typos, corrections and language improvements in the docs, and a few in
code comments too.

Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210409033703.GP6592%40telsasoft.com
2021-04-10 08:21:53 +12:00
Peter Eisentraut 49fb4e6b24 doc: Additional documentation for date_bin
Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Author: John Naylor <john.naylor@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/CAFBsxsEEm1nuhZmfVQxvu_i3nDDEuvNJ_WMrDo9whFD_jusp-A@mail.gmail.com
2021-04-09 21:55:08 +02:00
Alvaro Herrera 41badeaba8
Document ANALYZE storage parameters for partitioned tables
Commit 0827e8af70 added parameters for autovacuum to support
partitioned tables, but didn't add any docs.  Add them.

Discussion: https://postgr.es/m/20210408213051.GL6592@telsasoft.com
2021-04-09 13:38:07 -04:00
Michael Paquier 609b0652af Fix typos and grammar in documentation and code comments
Comment fixes are applied on HEAD, and documentation improvements are
applied on back-branches where needed.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20210408164008.GJ6592@telsasoft.com
Backpatch-through: 9.6
2021-04-09 13:53:07 +09:00
Fujii Masao 8ff1c94649 Allow TRUNCATE command to truncate foreign tables.
This commit introduces new foreign data wrapper API for TRUNCATE.
It extends TRUNCATE command so that it accepts foreign tables as
the targets to truncate and invokes that API. Also it extends postgres_fdw
so that it can issue TRUNCATE command to foreign servers, by adding
new routine for that TRUNCATE API.

The information about options specified in TRUNCATE command, e.g.,
ONLY, CACADE, etc is passed to FDW via API. The list of foreign tables to
truncate is also passed to FDW. FDW truncates the foreign data sources
that the passed foreign tables specify, based on those information.
For example, postgres_fdw constructs TRUNCATE command using them
and issues it to the foreign server.

For performance, TRUNCATE command invokes the FDW routine for
TRUNCATE once per foreign server that foreign tables to truncate belong to.

Author: Kazutaka Onishi, Kohei KaiGai, slightly modified by Fujii Masao
Reviewed-by: Bharath Rupireddy, Michael Paquier, Zhihong Yu, Alvaro Herrera, Stephen Frost, Ashutosh Bapat, Amit Langote, Daniel Gustafsson, Ibrar Ahmed, Fujii Masao
Discussion: https://postgr.es/m/CAOP8fzb_gkReLput7OvOK+8NHgw-RKqNv59vem7=524krQTcWA@mail.gmail.com
Discussion: https://postgr.es/m/CAJuF6cMWDDqU-vn_knZgma+2GMaout68YUgn1uyDnexRhqqM5Q@mail.gmail.com
2021-04-08 20:56:08 +09:00
Thomas Munro 1d257577e0 Optionally prefetch referenced data in recovery.
Introduce a new GUC recovery_prefetch, disabled by default.  When
enabled, look ahead in the WAL and try to initiate asynchronous reading
of referenced data blocks that are not yet cached in our buffer pool.
For now, this is done with posix_fadvise(), which has several caveats.
Better mechanisms will follow in later work on the I/O subsystem.

The GUC maintenance_io_concurrency is used to limit the number of
concurrent I/Os we allow ourselves to initiate, based on pessimistic
heuristics used to infer that I/Os have begun and completed.

The GUC wal_decode_buffer_size is used to limit the maximum distance we
are prepared to read ahead in the WAL to find uncached blocks.

Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (parts)
Reviewed-by: Andres Freund <andres@anarazel.de> (parts)
Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (parts)
Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com>
Tested-by: Dmitry Dolgov <9erthalion6@gmail.com>
Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com>
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
2021-04-08 23:20:42 +12:00