Commit Graph

51526 Commits

Author SHA1 Message Date
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
Tom Lane 7645376774 Rename find_em_expr_usable_for_sorting_rel.
I didn't particularly like this function name, as it fails to
express what's going on.  Also, returning the sort expression
alone isn't too helpful --- typically, a caller would also
need some other fields of the EquivalenceMember.  But the
sole caller really only needs a bool result, so let's make
it "bool relation_can_be_sorted_early()".

Discussion: https://postgr.es/m/91f3ec99-85a4-fa55-ea74-33f85a5c651f@swarm64.com
2021-04-20 11:37:36 -04:00
Tom Lane 3753982441 Fix planner failure in some cases of sorting by an aggregate.
An oversight introduced by the incremental-sort patches caused
"could not find pathkey item to sort" errors in some situations
where a sort key involves an aggregate or window function.

The basic problem here is that find_em_expr_usable_for_sorting_rel
isn't properly modeling what prepare_sort_from_pathkeys will do
later.  Rather than hoping we can keep those functions in sync,
let's refactor so that they actually share the code for
identifying a suitable sort expression.

With this refactoring, tlist.c's tlist_member_ignore_relabel
is unused.  I removed it in HEAD but left it in place in v13,
in case any extensions are using it.

Per report from Luc Vlaming.  Back-patch to v13 where the
problem arose.

James Coleman and Tom Lane

Discussion: https://postgr.es/m/91f3ec99-85a4-fa55-ea74-33f85a5c651f@swarm64.com
2021-04-20 11:32:02 -04:00
Andrew Dunstan 95c3a1956e Avoid unfortunate IPC::Run path caching in PostgresNode
Commit b34ca595ab provided for installation-aware instances of
PostgresNode. However, it turns out that IPC::Run works against this by
caching the path to a binary and not consulting the path again, even if
it has changed. We work around this by calling Postgres binaries with
the installed path rather than just a bare name to be looked up in the
environment path, if there is an installed path. For the common case
where there is no installed path we continue to use the bare command
name.

Diagnosis and solution from Mark Dilger

Discussion: https://postgr.es/m/E8F512F8-B4D6-4514-BA8D-2E671439DA92@enterprisedb.com
2021-04-20 10:36:10 -04:00
Magnus Hagander 8b4b5669cd Fix typo in comment
Author: Julien Rouhaud
Backpatch-through: 11
Discussion: https://postgr.es/m/20210420121659.odjueyd4rpilorn5@nol
2021-04-20 14:35:16 +02:00
Peter Geoghegan 7136bf34f2 Document LP_DEAD accounting issues in VACUUM.
Document VACUUM's soft assumption that any LP_DEAD items encountered
during pruning will become LP_UNUSED items before VACUUM finishes up.
This is integral to the accounting used by VACUUM to generate its final
report on the table to the stats collector.  It also affects how VACUUM
determines which heap pages are truncatable.  In both cases VACUUM is
concerned with the likely contents of the page in the near future, not
the current contents of the page.

This state of affairs created the false impression that VACUUM's dead
tuple accounting had significant difference with similar accounting used
during ANALYZE.  There were and are no substantive differences, at least
when the soft assumption completely works out.  This is far clearer now.

Also document cases where things don't quite work out for VACUUM's dead
tuple accounting.  It's possible that a significant number of LP_DEAD
items will be left behind by VACUUM, and won't be recorded as remaining
dead tuples in VACUUM's statistics collector report.  This behavior
dates back to commit a96c41fe, which taught VACUUM to run without index
and heap vacuuming at the user's request.  The failsafe mechanism added
to VACUUM more recently by commit 1e55e7d1 takes the same approach to
dead tuple accounting.

Reported-By: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wz=Jmtu18PrsYq3EvvZJGOmZqSO2u3bvKpx9xJa5uhNp=Q@mail.gmail.com
2021-04-19 18:55:31 -07:00
Peter Eisentraut 640b91c3ed Use correct format placeholder for pids
Should be signed, not unsigned.
2021-04-19 10:43:18 +02:00
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
Michael Paquier c731f9187b Replace magic constants for seek() calls in perl scripts
A couple of tests have been using 0 as magic constant while SEEK_SET can
be used instead.  This makes the code easier to understand, and more
consistent with the changes done in 3c5b068.

Per discussion with Andrew Dunstan.

Discussion: https://postgr.es/m/YHrc24AgJQ6tQ1q0@paquier.xyz
2021-04-19 10:15:35 +09:00
Thomas Munro 8e861eaae8 Explain postmaster's treatment of SIGURG.
Add a few words of comment to explain why SIGURG doesn't follow the
dummy_handler pattern used for SIGUSR2, since that might otherwise
appear to be a bug.

Discussion: https://postgr.es/m/4006115.1618577212%40sss.pgh.pa.us
2021-04-19 10:35:51 +12:00
Peter Eisentraut 4ed7f0599a Add missing source files to nls.mk 2021-04-18 16:11:58 +02:00
Peter Eisentraut f7c09706c1 doc: Fix up spacing around verbatim DocBook elements 2021-04-17 14:14:26 +02:00
Peter Eisentraut f59b58e2a1 Use correct format placeholder for block numbers
Should be %u rather than %d.
2021-04-17 09:40:50 +02:00
Tom Lane f24b156997 Rethink extraction of collation dependencies.
As it stands, find_expr_references_walker() pays attention to leaf-node
collation fields while ignoring the input collations of actual function
and operator nodes.  That seems exactly backwards from a semantic
standpoint, and it leads to reporting dependencies on collations that
really have nothing to do with the expression's behavior.

Hence, rewrite to look at function input collations instead.  This
isn't completely perfect either; it fails to account for the behavior
of record_eq and its siblings.  (The previous coding at least gave an
approximation of that, though I think it could be fooled pretty easily
into considering the columns of irrelevant composite types.)  We may
be able to improve on this later, but for now this should satisfy the
buildfarm members that didn't like ef387bed8.

In passing fix some oversights in GetTypeCollations(), and get
rid of its duplicative de-duplications.  (I'm worried that it's
still potentially O(N^2) or worse, but this makes it a little
better.)

Discussion: https://postgr.es/m/3564817.1618420687@sss.pgh.pa.us
2021-04-16 22:23:46 -04:00
Tom Lane 8a2df442b6 Update dummy prosrc values.
Ooops, forgot to s/system_views.sql/system_functions.sql/g
in this part of 767982e36.

No need for an additional catversion bump, I think, since
these strings are gone by the time initdb finishes.

Discussion: https://postgr.es/m/3956760.1618529139@sss.pgh.pa.us
2021-04-16 19:01:22 -04:00
Tom Lane 767982e362 Convert built-in SQL-language functions to SQL-standard-body style.
Adopt the new pre-parsed representation for all built-in and
information_schema SQL-language functions, except for a small
number that can't presently be converted because they have
polymorphic arguments.

This eliminates residual hazards around search-path safety of
these functions, and might provide some small performance benefits
by reducing parsing costs.  It seems useful also to provide more
test coverage for the SQL-standard-body feature.

Discussion: https://postgr.es/m/3956760.1618529139@sss.pgh.pa.us
2021-04-16 18:37:02 -04:00
Tom Lane e809493725 Split function definitions out of system_views.sql into a new file.
Invent system_functions.sql to carry the function definitions that
were formerly in system_views.sql.  The function definitions were
already a quarter of the file and are about to be more, so it seems
appropriate to give them their own home.

In passing, fix an oversight in dfb75e478: it neglected to call
check_input() for system_constraints.sql.

Discussion: https://postgr.es/m/3956760.1618529139@sss.pgh.pa.us
2021-04-16 18:37:02 -04:00
Andrew Dunstan 3c5b0685b9 Allow TestLib::slurp_file to skip contents, and use as needed
In order to avoid getting old logfile contents certain functions in
PostgresNode were doing one of two things. On Windows it rotated the
logfile and restarted the server, while elsewhere it truncated the log
file. Both of these are unnecessary. We borrow from the buildfarm which
does this instead: note the size of the logfile before we start, and
then when fetching the logfile skip to that position before accumulating
contents. This is spelled differently on Windows but the effect is the
same. This is largely centralized in TestLib's slurp_file function,
which has a new optional parameter, the offset to skip to before
starting to reading the file. Code in the client becomes much neater.

Backpatch to all live branches.

Michael Paquier, slightly modified by me.

Discussion: https://postgr.es/m/YHajnhcMAI3++pJL@paquier.xyz
2021-04-16 17:19:08 -04:00
Tom Lane ef387bed87 Fix bogus collation-version-recording logic.
recordMultipleDependencies had the wrong scope for its "version"
variable, allowing a version label to leak from the collation entry it
was meant for to subsequent non-collation entries.  This is relatively
hard to trigger because of the OID-descending order that the inputs
will normally arrive in: subsequent non-collation items will tend to
be pinned.  But it can be exhibited easily with a custom collation.

Also, don't special-case the default collation, but instead ignore
pinned-ness of a collation when we've found a version for it.  This
avoids creating useless pg_depend entries, and removes a not-very-
future-proof assumption that C, POSIX, and DEFAULT are the only
pinned collations.

A small problem is that, because the default collation may or may
not have a version, the regression tests can't assume anything about
whether dependency entries will be made for it.  This seems OK though
since it's now handled just the same as other collations, and we have
test cases for both versioned and unversioned collations.

Fixes oversights in commit 257836a75.  Thanks to Julien Rouhaud
for review.

Discussion: https://postgr.es/m/3564817.1618420687@sss.pgh.pa.us
2021-04-16 12:26:50 -04:00
Tom Lane f90c708a04 Fix wrong units in two ExplainPropertyFloat calls.
This is only a latent bug, since these calls are only reached for
non-text output formats, and currently none of those will print
the units.  Still, we should get it right in case that ever changes.

Justin Pryzby

Discussion: https://postgr.es/m/20210415163846.GA3315@telsasoft.com
2021-04-16 11:30:27 -04:00
Peter Eisentraut 029c5ac03d psql: Refine lexing of BEGIN...END blocks in CREATE FUNCTION statements
Only track BEGIN...END blocks if they are in a CREATE [OR REPLACE]
{FUNCTION|PROCEDURE} statement.  Ignore if in parentheses.

Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://www.postgresql.org/message-id/cee01d26fe55bc086b3bcf10bfe4e8d450e2f608.camel@cybertec.at
2021-04-16 12:20:23 +02:00
Peter Eisentraut 25593d7d33 psql: Small fixes for better translatability 2021-04-16 11:05:58 +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 409723365b Provide query source text when parsing a SQL-standard function body.
Without this, we lose error cursor positions, as shown in the
modified regression test result.

Discussion: https://postgr.es/m/2197698.1617984583@sss.pgh.pa.us
2021-04-15 17:24:12 -04:00
Tom Lane 83efce7a1e Revert "Cope with NULL query string in ExecInitParallelPlan()."
This reverts commit b3ee4c5038.
We don't need it in the wake of the preceding commit, which
added an upstream check that the querystring isn't null.

Discussion: https://postgr.es/m/2197698.1617984583@sss.pgh.pa.us
2021-04-15 17:17:45 -04:00
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
Tom Lane 3157cbe974 Stabilize recently-added information_schema test queries.
These queries could show unexpected entries if the core system,
or concurrently-running test scripts, created any functions that
would appear in the information_schema views.  Restrict them
to showing functions belonging to this test's schema, as the
far-older nearby test case does.

Per experimentation with conversion of some built-in functions
to SQL-function-body style.
2021-04-15 16:31:44 -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
Peter Eisentraut cbae8774eb pg_upgrade: Small fix for better translatability of help output 2021-04-15 09:08:18 +02:00
Peter Eisentraut 59da8d9eb7 amcheck: Use correct format placeholder for TOAST chunk numbers
Several of these were already fixed in passing in
9acaf1a621, but one was remaining
inconsistent.
2021-04-15 08:58:03 +02:00
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
Tom Lane e1623b7d86 Fix obsolete comments referencing JoinPathExtraData.extra_lateral_rels.
That field went away in commit edca44b15, but it seems that
commit 45be99f8c re-introduced some comments mentioning it.
Noted by James Coleman, though this isn't exactly his
proposed new wording.  Also thanks to Justin Pryzby for
software archaeology.

Discussion: https://postgr.es/m/CAAaqYe8fxZjq3na+XkNx4C78gDqykH-7dbnzygm9Qa9nuDTePg@mail.gmail.com
2021-04-14 14:28:24 -04:00
Robert Haas 9acaf1a621 amcheck: Reword some messages and fix an alignment problem.
We don't need to mention the attribute number in these messages, because
there's a dedicated column for that, but we should mention the toast
value ID, because that's really useful for any follow-up troubleshooting
the user wants to do. This also rewords some of the messages to hopefully
read a little better.

Also, use VARATT_EXTERNAL_GET_POINTER in case we're accessing a TOAST
pointer that isn't aligned on a platform that's fussy about alignment,
so that we don't crash while corruption-checking the user's data.

Mark Dilger, reviewed by me.

Discussion: http://postgr.es/m/7D3B9BF6-50D0-4C30-8506-1C1851C7F96F@enterprisedb.com
2021-04-14 12:46:31 -04:00
Peter Eisentraut 07e5e66742 Improve quoting in some error messages 2021-04-14 09:11:29 +02:00
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
Michael Paquier 93f4146144 Simplify tests of postgres_fdw terminating connections
The tests introduced in 32a9c0b for connections broken and
re-established rely on pg_terminate_backend() for their logic.  When
these were introduced, this function simply sent a signal to a backend
without waiting for the operation to complete, and the tests repeatedly
looked at pg_stat_activity to check if the operation was completed or
not.  Since aaf0432, it is possible to define a timeout to make
pg_terminate_backend() wait for a certain duration, so make use of it,
with a timeout reasonably large enough (3min) to give enough room for
the tests to pass even on slow machines.

Some measurements show that the tests of postgres_fdw are much faster
with this change.  For example, on my laptop, they now take 4s instead
of 6s.

Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACXGY_EfGrMTjKjHy2zi-u1u9rdeioU_fro0T6Jo8t56KQ@mail.gmail.com
2021-04-14 14:23:53 +09:00
Amit Kapila cca57c1d9b Use NameData datatype for slotname in stats.
This will make it consistent with the other usage of slotname in the code.
In the passing, change pgstat_report_replslot signature to use a structure
rather than multiple parameters.

Reported-by: Andres Freund
Author: Vignesh C
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
2021-04-14 08:55:03 +05:30
Tomas Vondra 20661c15db Initialize t_self and t_tableOid in statext_expressions_load
The function is building a fake heap tuple, but left some of the header
fields (tid and table OID) uninitialized. Per Coverity report.

Reported-by: Ranier Vilela
Discussion: https://postgr.es/m/CAEudQApj6h8tZ0-eP5Af5PKc5NG1YUc7=SdN_99YoHS51fKa0Q@mail.gmail.com
2021-04-14 00:46:12 +02:00
Peter Geoghegan 60f1f09ff4 Don't truncate heap when VACUUM's failsafe is in effect.
It seems like a good idea to bypass heap truncation when the wraparound
failsafe mechanism (which was added in commit 1e55e7d1) is in effect.

Deliberately don't bypass heap truncation in the INDEX_CLEANUP=off case,
even though it is similar to the failsafe case.  There is already a
separate reloption (and related VACUUM parameter) for that.

Reported-By: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CAD21AoDWRh6oTN5T8wa+cpZUVpHXET8BJ8Da7WHVHpwkPP6KLg@mail.gmail.com
2021-04-13 12:58:31 -07:00
Tom Lane 6c0373ab77 Allow table-qualified variable names in ON CONFLICT ... WHERE.
Previously you could only use unqualified variable names here.
While that's not a functional deficiency, since only the target
table can be referenced, it's a surprising inconsistency with the
rules for partial-index predicates, on which this syntax is
supposedly modeled.

The fix for that is no harder than passing addToRelNameSpace = true
to addNSItemToQuery.  However, it's really pretty bogus for
transformOnConflictArbiter and transformOnConflictClause to be
messing with the namespace item for the target table at all.
It's not theirs to manage, it results in duplicative creations of
namespace items, and transformOnConflictClause wasn't even doing
it quite correctly (that coding resulted in two nsitems for the
target table, since it hadn't cleaned out the existing one).
Hence, make transformInsertStmt responsible for setting up the
target nsitem once for both these clauses and RETURNING.

Also, arrange for ON CONFLICT ... UPDATE's "excluded" pseudo-relation
to be added to the rangetable before we run transformOnConflictArbiter.
This produces a more helpful HINT if someone writes "excluded.col"
in the arbiter expression.

Per bug #16958 from Lukas Eder.  Although I agree this is a bug,
the consequences are hardly severe, so no back-patch.

Discussion: https://postgr.es/m/16958-963f638020de271c@postgresql.org
2021-04-13 15:39:41 -04:00
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
Tom Lane 69d5ca484b Fix some inappropriately-disallowed uses of ALTER ROLE/DATABASE SET.
Most GUC check hooks that inspect database state have special checks
that prevent them from throwing hard errors for state-dependent issues
when source == PGC_S_TEST.  This allows, for example,
"ALTER DATABASE d SET default_text_search_config = foo" when the "foo"
configuration hasn't been created yet.  Without this, we have problems
during dump/reload or pg_upgrade, because pg_dump has no idea about
possible dependencies of GUC values and can't ensure a safe restore
ordering.

However, check_role() and check_session_authorization() hadn't gotten
the memo about that, and would throw hard errors anyway.  It's not
entirely clear what is the use-case for "ALTER ROLE x SET role = y",
but we've now heard two independent complaints about that bollixing
an upgrade, so apparently some people are doing it.

Hence, fix these two functions to act more like other check hooks
with similar needs.  (But I did not change their insistence on
being inside a transaction, as it's still not apparent that setting
either GUC from the configuration file would be wise.)

Also fix check_temp_buffers, which had a different form of the disease
of making state-dependent checks without any exception for PGC_S_TEST.
A cursory survey of other GUC check hooks did not find any more issues
of this ilk.  (There are a lot of interdependencies among
PGC_POSTMASTER and PGC_SIGHUP GUCs, which may be a bad idea, but
they're not relevant to the immediate concern because they can't be
set via ALTER ROLE/DATABASE.)

Per reports from Charlie Hornsby and Nathan Bossart.  Back-patch
to all supported branches.

Discussion: https://postgr.es/m/HE1P189MB0523B31598B0C772C908088DB7709@HE1P189MB0523.EURP189.PROD.OUTLOOK.COM
Discussion: https://postgr.es/m/20160711223641.1426.86096@wrigleys.postgresql.org
2021-04-13 15:10:18 -04:00
Tom Lane c2db458c10 Redesign the caching done by get_cached_rowtype().
Previously, get_cached_rowtype() cached a pointer to a reference-counted
tuple descriptor from the typcache, relying on the ExprContextCallback
mechanism to release the tupdesc refcount when the expression tree
using the tupdesc was destroyed.  This worked fine when it was designed,
but the introduction of within-DO-block COMMITs broke it.  The refcount
is logged in a transaction-lifespan resource owner, but plpgsql won't
destroy simple expressions made within the DO block (before its first
commit) until the DO block is exited.  That results in a warning about
a leaked tupdesc refcount when the COMMIT destroys the original resource
owner, and then an error about the active resource owner not holding a
matching refcount when the expression is destroyed.

To fix, get rid of the need to have a shutdown callback at all, by
instead caching a pointer to the relevant typcache entry.  Those
survive for the life of the backend, so we needn't worry about the
pointer becoming stale.  (For registered RECORD types, we can still
cache a pointer to the tupdesc, knowing that it won't change for the
life of the backend.)  This mechanism has been in use in plpgsql
and expandedrecord.c since commit 4b93f5799, and seems to work well.

This change requires modifying the ExprEvalStep structs used by the
relevant expression step types, which is slightly worrisome for
back-patching.  However, there seems no good reason for extensions
to be familiar with the details of these particular sub-structs.

Per report from Rohit Bhogate.  Back-patch to v11 where within-DO-block
COMMITs became a thing.

Discussion: https://postgr.es/m/CAAV6ZkQRCVBh8qAY+SZiHnz+U+FqAGBBDaDTjF2yiKa2nJSLKg@mail.gmail.com
2021-04-13 13:37:07 -04:00
Tom Lane 34f581c39e Avoid improbable PANIC during heap_update.
heap_update needs to clear any existing "all visible" flag on
the old tuple's page (and on the new page too, if different).
Per coding rules, to do this it must acquire pin on the appropriate
visibility-map page while not holding exclusive buffer lock;
which creates a race condition since someone else could set the
flag whenever we're not holding the buffer lock.  The code is
supposed to handle that by re-checking the flag after acquiring
buffer lock and retrying if it became set.  However, one code
path through heap_update itself, as well as one in its subroutine
RelationGetBufferForTuple, failed to do this.  The end result,
in the unlikely event that a concurrent VACUUM did set the flag
while we're transiently not holding lock, is a non-recurring
"PANIC: wrong buffer passed to visibilitymap_clear" failure.

This has been seen a few times in the buildfarm since recent VACUUM
changes that added code paths that could set the all-visible flag
while holding only exclusive buffer lock.  Previously, the flag
was (usually?) set only after doing LockBufferForCleanup, which
would insist on buffer pin count zero, thus preventing the flag
from becoming set partway through heap_update.  However, it's
clear that it's heap_update not VACUUM that's at fault here.

What's less clear is whether there is any hazard from these bugs
in released branches.  heap_update is certainly violating API
expectations, but if there is no code path that can set all-visible
without a cleanup lock then it's only a latent bug.  That's not
100% certain though, besides which we should worry about extensions
or future back-patch fixes that could introduce such code paths.

I chose to back-patch to v12.  Fixing RelationGetBufferForTuple
before that would require also back-patching portions of older
fixes (notably 0d1fe9f74), which is more code churn than seems
prudent to fix a hypothetical issue.

Discussion: https://postgr.es/m/2247102.1618008027@sss.pgh.pa.us
2021-04-13 12:17:24 -04:00