Michael Paquier [Wed, 4 Mar 2026 04:05:31 +0000 (13:05 +0900)]
Change default value of default_toast_compression to "lz4", when available
The default value for default_toast_compression was "pglz". The main
reason for this choice is that this option is always available, pglz
code being embedded in Postgres. However, it is known that LZ4 is more
efficient than pglz: less CPU required, more compression on average. As
of this commit, the default value of default_toast_compression becomes
"lz4", if available. By switching to LZ4 as the default, users should
see natural speedups on TOAST data reads and/or writes.
Support for LZ4 in TOAST compression was added in Postgres v14, or 5
releases ago. This should be long enough to consider this feature as
stable.
--with-lz4 is removed, replaced by a --without-lz4 to disable LZ4 in the
builds on an option-basis, following a practice similar to readline or
ICU. References to --with-lz4 are removed from the documentation.
While at it, quotes are removed from default_toast_compression in
postgresql.conf.sample. Quotes are not required in this case. The
in-place value replacement done by initdb if the build supports LZ4
would not use them in the postgresql.conf file added to a
freshly-initialized cluster.
For the reference, a similar switch has been done with ICU in fcb21b3acdcb. Some of the changes done in this commit are consistent
with that.
Note: this is going to create some disturbance in the buildfarm, in
environments where lz4 is not installed.
Author: Euler Taveira <euler@eulerto.com> Reviewed-by: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: Aleksander Alekseev <aleksander@tigerdata.com>
Discussion: https://posgr.es/m/435df33a-129e-4f0c-a803-f3935c5a5ecb@eisentraut.org
Richard Guo [Wed, 4 Mar 2026 01:57:43 +0000 (10:57 +0900)]
Remove redundant restriction checks in apply_child_basequals
In apply_child_basequals, after translating a parent relation's
restriction quals for a child relation, we simplify each child qual by
calling eval_const_expressions. Historically, the code then called
restriction_is_always_false and restriction_is_always_true to reduce
NullTest quals that are provably false or true.
However, since commit e2debb643, the planner natively performs
NullTest deduction during constant folding. Therefore, calling
restriction_is_always_false and restriction_is_always_true immediately
afterward is redundant and wastes CPU cycles. We can safely remove
them and simply rely on the constant folding to handle the deduction.
Author: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CAMbWs4-vLmGXaUEZyOMacN0BVfqWCt2tM-eDVWdDfJnOQaauGg@mail.gmail.com
Richard Guo [Wed, 4 Mar 2026 01:56:06 +0000 (10:56 +0900)]
Remove obsolete SAMESIGN macro
The SAMESIGN macro was historically used as a helper for manual
integer overflow checks. However, since commit 4d6ad3125 introduced
overflow-aware integer operations, this manual sign-checking logic is
no longer necessary.
The macro remains defined in brin_minmax_multi.c and timestamp.c, but
is not used in either file. This patch removes these definitions to
clean things up.
Author: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CAMbWs4-NL3J3hQ3LzrwV-YUkQC18P+jM7ZiegQyAHzgdZev2qg@mail.gmail.com
Michael Paquier [Wed, 4 Mar 2026 00:55:58 +0000 (09:55 +0900)]
Add some tests for CREATE OR REPLACE VIEW with column additions
When working on an already-defined view with matching attributes, CREATE
OR REPLACE VIEW would internally generate an ALTER TABLE command with a
set of AT_AddColumnToView sub-commands, one for each attribute added.
Such a command is stored in event triggers twice:
- Once as a simple command.
- Once as an ALTER TABLE command, as it has sub-commands.
There was no test coverage to track this command pattern in terms of
event triggers and DDL deparsing:
- For the test module test_ddl_deparse, two command notices are issued.
- For event triggers, a CREATE VIEW command is logged twice, which may
look a bit weird first, but again this maps with the internal behavior
of how the commands are built, and how the event trigger code reacts in
terms of commands gathered.
While on it, this adds a test for CREATE SCHEMA with a CREATE VIEW
command embedded in it, case supported by the grammar but not covered
yet.
This hole in the test coverage has been found while digging into what
would be a similar behavior for sequences if adding attributes to them
with ALTER TABLE variants, after the initial relation creation.
Read stream users can now pause lookahead when no blocks are currently
available. After resuming, subsequent read_stream_next_buffer() calls
continue lookahead with the previous lookahead distance.
This is especially useful for read stream users with self-referential
access patterns (where consuming already-read buffers can produce
additional block numbers).
Author: Thomas Munro <thomas.munro@gmail.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJLT2JvWLEiBXMbkSSc5so_Y7%3DN%2BS2ce7npjLw8QL3d5w%40mail.gmail.com
doc: Add restart on failure to example systemd file
The documentation previously had a systemd unit file that would not
attempt to recover from process failures such as OOM's, segfaults,
etc. This commit adds "Restart=on-failure",` which tells systemd to
attempt to restart the process after failure. This is the recommended
configuration per the systemd documentation: "Setting this to
on-failure is the recommended choice for long-running services". Many
PostgreSQL users will simply copy/paste what the PostgreSQL
documentation recommends and will probably do their own research and
change the service file to restart on failure, so might as well set
this as the default in the PostgreSQL documentation.
Author: Andrew Jackson <andrewjackson947@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAKK5BkFfMpAQnv8CLs%3Di%3DrZwurtCV_gmfRb0uZi-V%2Bd6wcryqg%40mail.gmail.com
Álvaro Herrera [Tue, 3 Mar 2026 10:19:23 +0000 (11:19 +0100)]
Reduce scope of for-loop-local variables to avoid shadowing
Adjust a couple of for-loops where a local variable was shadowed by
another in the same scope, by renaming it as well as reducing its scope
to the containing for-loop.
Author: Chao Li <lic@highgo.com> Reviewed-by: Peter Smith <smithpb2250@gmail.com> Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Discussion: https://postgr.es/m/CAEoWx2kQ2x5gMaj8tHLJ3=jfC+p5YXHkJyHrDTiQw2nn2FJTmQ@mail.gmail.com
Commit c66a7d75e652 introduced a new "cast discards ‘volatile’"
warning (-Wcast-qual) in vac_truncate_clog().
Instead of making use of unvolatize(), remove the warning by reducing the
scope of the volatile qualifier (added in commit 2d2e40e3bef) to only
2 fields.
Also do the same for vac_update_datfrozenxid(), since the intent of
commit f65ab862e3b was to prevent the same kind of race condition that
commit 2d2e40e3bef was fixing.
If ON_ERROR SET_NULL is specified during COPY FROM, any data type
conversion errors will result in the affected column being set to a
null value. A column's not-null constraints are still enforced, and
attempting to set a null value in such columns will raise a constraint
violation error. This applies to a column whose data type is a domain
with a NOT NULL constraint.
Author: Jian He <jian.universality@gmail.com>
Author: Kirill Reshke <reshkekirill@gmail.com> Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com> Reviewed-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: "David G. Johnston" <david.g.johnston@gmail.com> Reviewed-by: Yugo NAGATA <nagata@sraoss.co.jp> Reviewed-by: torikoshia <torikoshia@oss.nttdata.com> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Atsushi Torikoshi <torikoshia@oss.nttdata.com> Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com> Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://www.postgresql.org/message-id/flat/CAKFQuwawy1e6YR4S%3Dj%2By7pXqg_Dw1WBVrgvf%3DBP3d1_aSfe_%2BQ%40mail.gmail.com
Michael Paquier [Tue, 3 Mar 2026 06:27:50 +0000 (15:27 +0900)]
doc: Fix sentence of pg_walsummary page
Author: Peter Smith <smithpb2250@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Robert Treat <rob@xzilla.net>
Discussion: https://postgr.es/m/CAHut+PvfYBL-ppX-i8DPeRu7cakYCZz+QYBhrmQzicx7z_Tj5w@mail.gmail.com
Backpatch-through: 17
Michael Paquier [Tue, 3 Mar 2026 05:19:54 +0000 (14:19 +0900)]
Add support for "exprs" in pg_restore_extended_stats()
This commit adds support for the restore of extended statistics of the
kind "exprs", counting for the statistics data computed for expressions.
The input format consists of a jsonb object which must be an array of
objects which are keyed by statistics parameter names, like this:
[{"stat_type1": "...", "stat_type2": "...", ...},
{"stat_type1": "...", "stat_type2": "...", ...}, ...]
The outer array must have as many elements as there are expressions
defined in the statistics object, mapping with the way extended
statistics are built with one pg_statistic tuple stored for each
expression whose statistics have been computed. The elements of the
array must be either objects or null values (equivalent of invalid data,
case also supported by the stats computations when its data is inserted
in the catalogs).
The keys of the inner objects are names of the statistical columns in
pg_stats_ext_exprs (i.e. everything after "inherited"). Not all
parameter keys need to be provided, those omitted being silently
ignored. Key values that do not match a statistical column name will
cause a warning to be issued, but do not otherwise fail the expression
or the import as a whole.
The expected value type for all parameters is jbvString, which allows
us to validate the values using the input function specific to that
parameter. Any parameters with a null value are silently ignored, same
as if they were not provided in the first place.
This commit includes a battery of test cases:
- Sanity checks for what-should-be-all the failures in restore code
paths, including parsing errors, parameter sanity checks depending on
the extended stats object definition, etc.
- Value injection, for scalar, array, range, multi-range cases.
- Stats data cloning, with differential checks between the source
relation and its target. The source and the target should hold the same
stats data after restore.
- While expressions are supported in extended statistics since v14,
range_length_histogram, range_empty_frac, and range_bounds_histogram
have been added to pg_stat_ext_exprs only in v19. A test case has been
added to emulate a dump taken from v18, with expression stats restored
for a range data type where these three fields are NULL.
Support for pg_dump is included, with expressions supported since v14,
inherited since v15, and data for range types in expressions in v19.
pg_upgrade is the main use-case of this feature; it is also possible to
inject statistics, same as for the other extstat kinds.
As of this commit, ANALYZE should not be required after pg_upgrade when
the cluster upgrading from uses extended statistics, as MCV,
dependencies, expressions and ndistinct stats are all covered. The
stats data related to range types used in expressions requires v19,
whose support has also been added.
Author: Corey Huinker <corey.huinker@gmail.com> Co-authored-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CADkLM=fPcci6oPyuyEZ0F4bWqAA7HzaWO+ZPptufuX5_uWt6kw@mail.gmail.com
Tom Lane [Mon, 2 Mar 2026 19:40:29 +0000 (14:40 -0500)]
Fix local-variable shadowing in pg_trgm's printSourceNFA().
We hadn't noticed this violation of -Wshadow=compatible-local
because this function isn't compiled without -DTRGM_REGEXP_DEBUG.
As long as we have to clean it up, let's do so by converting all
this function's loops to use C99 loop-local control variables.
Reported-by: Sergei Kornilov <sk@zsrv.org>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3009911772478436@08341ecb-668d-43a9-af4d-b45f00c72521
Nathan Bossart [Mon, 2 Mar 2026 19:12:25 +0000 (13:12 -0600)]
basic_archive: Allow archive directory to be missing at startup.
Presently, the GUC check hook for basic_archive.archive_directory
checks that the specified directory exists. Consequently, if the
directory does not exist at server startup, archiving will be stuck
indefinitely, even if it appears later. To fix, remove this check
from the hook so that archiving will resume automatically once the
directory is present. basic_archive must already be prepared to
deal with the directory disappearing at any time, so no additional
special handling is required.
Reported-by: Олег Самойлов <splarv@ya.ru> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Fujii Masao <masao.fujii@gmail.com> Reviewed-by: Sergei Kornilov <sk@zsrv.org>
Discussion: https://postgr.es/m/73271769675212%40mail.yandex.ru
Backpatch-through: 15
Fix OldestMemberMXactId and OldestVisibleMXactId array usage
Commit ab355e3a88 changed how the OldestMemberMXactId array is
indexed. It's no longer indexed by synthetic dummyBackendId, but with
ProcNumber. The PGPROC entries for prepared xacts come after auxiliary
processes in the allProcs array, which rendered the calculation for
MaxOldestSlot and the indexes into the array incorrect. (The
OldestVisibleMXactId array is not used for prepared xacts, and thus
never accessed with ProcNumber's greater than MaxBackends, so this
only affects the OldestMemberMXactId array.)
As a result, a prepared xact would store its value past the end of the
OldestMemberMXactId array, overflowing into the OldestVisibleMXactId
array. That could cause a transaction's row lock to appear invisible
to other backends, or other such visibility issues. With a very small
max_connections setting, the store could even go beyond the
OldestVisibleMXactId array, stomping over the first element in the
BufferDescriptor array.
To fix, calculate the array sizes more precisely, and introduce helper
functions to calculate the array indexes correctly.
Author: Yura Sokolov <y.sokolov@postgrespro.ru> Reviewed-by: Sami Imseih <samimseih@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/7acc94b0-ea82-4657-b1b0-77842cb7a60c@postgrespro.ru
Backpatch-through: 17
Tom Lane [Mon, 2 Mar 2026 16:14:58 +0000 (11:14 -0500)]
In pg_dumpall, don't skip role GRANTs with dangling grantor OIDs.
In commits 29d75b25b et al, I made pg_dumpall's dumpRoleMembership
logic treat a dangling grantor OID the same as dangling role and
member OIDs: print a warning and skip emitting the GRANT. This wasn't
terribly well thought out; instead, we should handle the case by
emitting the GRANT without the GRANTED BY clause. When the source
database is pre-v16, such cases are somewhat expected because those
versions didn't prevent dropping the grantor role; so don't even
print a warning that we did this. (This change therefore restores
pg_dumpall's pre-v16 behavior for these cases.) The case is not
expected in >= v16, so then we do print a warning, but soldiering on
with no GRANTED BY clause still seems like a reasonable strategy.
Per complaint from Robert Haas that we were now dropping GRANTs
altogether in easily-reachable scenarios.
Reported-by: Robert Haas <robertmhaas@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA+TgmoauoiW4ydDhdrseg+DD4Kwha=+TSZp18BrJeHKx3o1Fdw@mail.gmail.com
Backpatch-through: 16
Save prune cycles by consistently clearing prune hints on all-visible pages
All-visible pages can't contain prunable tuples. We already clear the
prune hint (pd_prune_xid) during pruning of all-visible pages, but we
were not doing so in vacuum phase three, nor initializing it for
all-frozen pages created by COPY FREEZE, and we were not clearing it on
standbys.
Because page hints are not WAL-logged, pages on a standby carry stale
pd_prune_xid values. After promotion, that stale hint triggers
unnecessary on-access pruning.
Fix this by clearing the prune hint everywhere we currently mark a heap
page all-visible. Clearing it when setting PD_ALL_VISIBLE ensures no
extra overhead.
Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/flat/CAAKRu_b-BMOyu0X-0jc_8bWNSbQ5K6JTEueayEhcQuw-OkCSKg%40mail.gmail.com
Calling copyObject in C++ without GNU extensions (e.g. when using
-std=c++11 instead of -std=gnu++11) fails with an error like this:
error: use of undeclared identifier 'typeof'; did you mean 'typeid'
This is due to the C compiler used to compile PostgreSQL supporting
typeof, but that function actually not being present in the C++
compiler. This fixes that by explicitely checking for typeof support
in C++, and then either use that or define typeof ourselves as:
std::remove_reference_t<decltype(x)>
According to the paper that led to adding typeof to the C standard,
that's the C++ equivalent of the C typeof:
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2927.htm#existing-decltype
Michael Paquier [Mon, 2 Mar 2026 05:13:05 +0000 (14:13 +0900)]
Remove WAL page header flag XLP_BKP_REMOVABLE
There are no known users of this flag. The last supposed user was
pglesslog, which is the reason why this flag has been introduced in
core, based on an historical search pointing at a8d539f12498.
I have mentioned that we may want to remove this flag back in 2018, due
to zero users of it in core. More recently, Noah has pointed out that
this flag is not safe to use: XLP_BKP_REMOVABLE can be set by the WAL
writer in a lock-free fashion with runningBackups > 0, meaning that some
full-page images could be required but not logged, ultimately corrupting
backups.
Bump XLOG_PAGE_MAGIC.
Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/20250705001628.c3.nmisch@google.com
Discussion: https://postgr.es/m/CAEze2WhiwKSoAvfUggjDeoeY0-rz9cTpfrHcqvBMmJxv-K_5DA@mail.gmail.com
Michael Paquier [Mon, 2 Mar 2026 04:14:15 +0000 (13:14 +0900)]
Fix memory allocation size in RegisterExtensionExplainOption()
The allocations used for the static array ExplainExtensionOptionArray,
that tracks a set of ExplainExtensionOption, used "char *" instead of
ExplainExtensionOption as the memory size consumed by one element,
underestimating the memory required by half.
The initial allocation of ExplainExtensionNameArray wants to hold 16
elements before being reallocated, and with "char *" it meant that there
was enough space only for 8 ExplainExtensionOption elements, 16 bytes
required for each element. The backend would crash once one tries to
register a 9th EXPLAIN option.
As far as I can see, the allocation formulas of GetExplainExtensionId()
have been copy-pasted to RegisterExtensionExplainOption(), but the
internal maths of the copy were not adjusted accordingly.
Michael Paquier [Mon, 2 Mar 2026 02:10:31 +0000 (11:10 +0900)]
test_custom_types: Test module with fancy custom data types
This commit adds a new test module called "test_custom_types", that can
be used to stress code paths related to custom data type
implementations.
Currently, this is used as a test suite to validate the set of fixes
done in 3b7a6fa15720, that requires some typanalyze callbacks that can
force very specific backend behaviors, as of:
- typanalyze callback that returns "false" as status, to mark a failure
in computing statistics.
- typanalyze callback that returns "true" but let's the backend know
that no interesting stats could be computed, with stats_valid set to
"false".
This could be extended more in the future if more problems are found.
For simplicity, the module uses a fake int4 data type, that requires a
btree operator class to be usable with extended statistics. The type is
created by the extension, and its properties are altered in the test.
Like 3b7a6fa15720, this module is backpatched down to v14, for coverage
purposes.
Author: Michael Paquier <michael@paquier.xyz> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/aaDrJsE1I5mrE-QF@paquier.xyz
Backpatch-through: 14
Fujii Masao [Mon, 2 Mar 2026 02:07:42 +0000 (11:07 +0900)]
psql: Add tab completion for DELETE ... USING.
This implements the tab completion that was marked as XXX TODO in the
source code. The following completion is now supported:
DELETE FROM <table> USING <TAB> -> list of relations supporting SELECT
This uses Query_for_list_of_selectables (instead of Query_for_list_of_tables)
because the USING clause can reference not only tables but also views and
other selectable objects, following the same syntax as the FROM clause
of a SELECT statement.
Michael Paquier [Mon, 2 Mar 2026 00:38:37 +0000 (09:38 +0900)]
Fix set of issues with extended statistics on expressions
This commit addresses two defects regarding extended statistics on
expressions:
- When building extended statistics in lookup_var_attr_stats(), the call
to examine_attribute() did not account for the possibility of a NULL
return value. This can happen depending on the behavior of a typanalyze
callback — for example, if the callback returns false, if no rows are
sampled, or if no statistics are computed. In such cases, the code
attempted to build MCV, dependency, and ndistinct statistics using a
NULL pointer, incorrectly assuming valid statistics were available,
which could lead to a server crash.
- When loading extended statistics for expressions,
statext_expressions_load() did not account for NULL entries in the
pg_statistic array storing expression statistics. Such NULL entries can
be generated when statistics collection fails for an expression, as may
occur during the final step of serialize_expr_stats(). An extended
statistics object defining N expressions requires N corresponding
elements in the pg_statistic array stored for the expressions, and some
of these elements can be NULL. This situation is reachable when a
typanalyze callback returns true, but sets stats_valid to indicate that
no useful statistics could be computed.
While these scenarios cannot occur with in-core typanalyze callbacks, as
far as I have analyzed, they can be triggered by custom data types with
custom typanalyze implementations, at least.
No tests are added in this commit. A follow-up commit will introduce a
test module that can be extended to cover similar edge cases if
additional issues are discovered. This takes care of the core of the
problem.
Attribute and relation statistics already offer similar protections:
- ANALYZE detects and skips the build of invalid statistics.
- Invalid catalog data is handled defensively when loading statistics.
This issue exists since the support for extended statistics on
expressions has been added, down to v14 as of a4d75c86bf15. Backpatch
to all supported stable branches.
Author: Michael Paquier <michael@paquier.xyz> Reviewed-by: Corey Huinker <corey.huinker@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/aaDrJsE1I5mrE-QF@paquier.xyz
Backpatch-through: 14
Tom Lane [Sun, 1 Mar 2026 17:56:55 +0000 (12:56 -0500)]
Correctly calculate "MCV frequency" for a unique column.
In commit bd3e3e9e5, I over-hastily used 1 / rel->rows as the assumed
frequency of entries in a column that ANALYZE has found to be unique.
However, rel->rows is the number of table rows that are estimated to
pass the query's restriction conditions, so that we got a too-large
result if the query has selective restrictions. What I should have
used is 1 / rel->tuples, since that is the estimated total number of
table rows. The pre-existing code path that digs a frequency out of
the histogram produces a frequency relative to the whole table, so
surely this new alternative code path must do so as well. Any
correction needed on the basis of selectivity must be done by the
user of the mcv_freq value.
Fixing this causes all the regression test plans changed by bd3e3e9e5
to revert to what they had been, except for the first change in
join.out. As I correctly argued in bd3e3e9e5, in that test case we
have no stats and should not risk a hash join. Evidently I was less
correct to argue that the other changes were improvements.
Reported-by: Joel Jacobson <joel@compiler.org> Diagnosed-by: Tender Wang <tndrwang@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/341b723c-da45-4058-9446-1514dedb17c1@app.fastmail.com
Fujii Masao [Sat, 28 Feb 2026 14:56:46 +0000 (23:56 +0900)]
psql: Show comments in \dRp+, \dRs+, and \dX+ psql meta-commands.
Previously, the psql meta-commands that list publications, subscriptions,
and extended statistics did not display their associated comments,
whereas other \d meta-commands did. This made it inconvenient for users
to view these objects together with their descriptions.
This commit improves \dRp+ and \dRs+ to include comments for publications
and subscriptions. It also extends the \dX meta-command to accept the + option,
allowing comments for extended statistics to be shown when requested.
Author: Fujii Masao <masao.fujii@gmail.com> Co-authored-by: Jim Jones <jim.jones@uni-muenster.de> Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAHGQGwGL4JqiKA26fnGx-cTM=VzoTs_uzqejvj4Fawyr4uLUUw@mail.gmail.com
Tom Lane [Fri, 27 Feb 2026 20:20:16 +0000 (15:20 -0500)]
Doc: improve user docs and code comments about EXISTS(SELECT * ...).
Point out that Postgres automatically optimizes away the target list
of an EXISTS' subquery, except in weird cases such as target lists
containing set-returning functions. Thus, both common conventions
EXISTS(SELECT * FROM ...) and EXISTS(SELECT 1 FROM ...) are
overhead-free and there's little reason to prefer one over the other.
In the code comments, mention that the SQL spec says that
EXISTS(SELECT * FROM ...) should be interpreted as EXISTS(SELECT
some-literal FROM ...), but we don't choose to do it exactly that way.
Author: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/9b301c70-3909-4f0f-98ca-9e3c4d142f3e@eisentraut.org
Tom Lane [Fri, 27 Feb 2026 17:54:02 +0000 (12:54 -0500)]
Don't flatten join alias Vars that are stored within a GROUP RTE.
The RTE's groupexprs list is used for deparsing views, and for that
usage it must contain the original alias Vars; else we can get
incorrect SQL output. But since commit 247dea89f,
parseCheckAggregates put the GROUP BY expressions through
flatten_join_alias_vars before building the RTE_GROUP RTE.
Changing the order of operations there is enough to fix it.
This patch unfortunately can do nothing for already-created views:
if they use a coding pattern that is subject to the bug, they will
deparse incorrectly and hence present a dump/reload hazard in the
future. The only fix is to recreate the view from the original SQL.
But the trouble cases seem to be quite narrow. AFAICT the output
was only wrong for "SELECT ... t1 LEFT JOIN t2 USING (x) GROUP BY x"
where t1.x and t2.x were not of identical data types and t1.x was
the side that required an implicit coercion. If there was no hidden
coercion, or if the join was plain, RIGHT, or FULL, the deparsed
output was uglier than intended but not functionally wrong.
Reported-by: Swirl Smog Dowry <swirl-smog-dowry@duck.com>
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CA+-gibjCg_vjcq3hWTM0sLs3_TUZ6Q9rkv8+pe2yJrdh4o4uoQ@mail.gmail.com
Backpatch-through: 18
John Naylor [Fri, 27 Feb 2026 13:30:41 +0000 (20:30 +0700)]
Centralize detection of x86 CPU features
We now maintain an array of booleans that indicate which features were
detected at runtime. When code wants to check for a given feature,
the array is automatically checked if it has been initialized and if
not, a single function checks all features at once.
Move all x86 feature detection to pg_cpu_x86.c, and move the CRC
function choosing logic to the file where the hardware-specific
functions are defined, consistent with more recent hardware-specific
files in src/port.
Andrew Dunstan [Fri, 27 Feb 2026 12:14:06 +0000 (07:14 -0500)]
Clean up nodes that are no longer of use in 007_pgdumpall.pl
Oversight in commit 763aaa06f03. When nodes are going out of scope, we
should stop the underlying postmasters rather than waiting for the
script to end.
Michael Paquier [Fri, 27 Feb 2026 09:59:41 +0000 (18:59 +0900)]
Use pg_malloc_object() and pg_alloc_array() variants in frontend code
This commit updates the frontend tools (src/bin/, contrib/ and
src/test/) to use the memory allocation variants based on
pg_malloc_object() and pg_malloc_array() in various code paths. This
does not cover all the allocations, but a good chunk of them.
Like all the changes of this kind (31d3847a37be, etc.), this should
encourage any future code to use this new style.
Author: Andreas Karlsson <andreas@proxel.se>
Discussion: https://postgr.es/m/cfb645da-6b3a-4f22-9bcc-5bc46b0e9c61@proxel.se
heapam_scan_analyze_next_tuple() doesn't distinguish between dead and
recently dead tuples when counting them, so it doesn't need OldestXmin.
GetOldestNonRemovableTransactionId() isn't free, so removing it is a
win.
Looking at other table AMs implementing table_scan_analyze_next_tuple(),
we couldn't find one using OldestXmin either, so remove it from the
callback.
Melanie Plageman [Thu, 26 Feb 2026 20:33:36 +0000 (15:33 -0500)]
Simplify visibility check in heap_page_would_be_all_visible()
heap_page_would_be_all_visible() does not need to distinguish between
HEAPTUPLE_RECENTLY_DEAD and HEAPTUPLE_DEAD tuples: any tuple in a state
other than HEAPTUPLE_LIVE means the page is not all-visible and
heap_page_would_be_all_visible() returns false.
Given that, calling HeapTupleSatisfiesVacuum() is unnecessary, since it
performs extra work to distinguish between dead and recently dead tuples
using OldestXmin. Replace it with the more minimal
HeapTupleSatisfiesVacuumHorizon().
Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Kirill Reshke <reshkekirill@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CALdSSPjvhGXihT_9f-GJabYU%3D_PjrFDUxYaURuTbfLyQM6TErg%40mail.gmail.com
Jeff Davis [Thu, 26 Feb 2026 20:23:22 +0000 (12:23 -0800)]
Fix more multibyte issues in ltree.
Commit 84d5efa7e3 missed some multibyte issues caused by short-circuit
logic in the callers. The callers assumed that if the predicate string
is longer than the label string, then it couldn't possibly be a match,
but it can be when using case-insensitive matching (LVAR_INCASE) if
casefolding changes the byte length.
Fix by refactoring to get rid of the short-circuit logic as well as
the function pointer, and consolidate the logic in a replacement
function ltree_label_match().
Melanie Plageman [Thu, 26 Feb 2026 20:04:49 +0000 (15:04 -0500)]
Rename LVRelState VM-related logging counters
The LVRelState fields that track newly all-visible/all-frozen pages were
previously named vm_new_visible_pages, vm_new_frozen_pages, and
vm_new_visible_frozen_pages. The correct terminology is all-visible and
all-frozen; omitting “all” was open to misinterpretation, as the page
isn't visible or invisible, rather all the tuples on the page are
visible to all running and future transactions. Rename the members
accordingly.
Author: Melanie Plageman <melanieplageman@gmail.com> Suggested-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/bqc4kh5midfn44gnjiqez3bjqv4zogydguvdn446riw45jcf3y%404ez66il7ebvk
Andres Freund [Thu, 26 Feb 2026 15:19:23 +0000 (10:19 -0500)]
instrumentation: Rename INSTR_TIME_LT macro to INSTR_TIME_GT
This was incorrectly named "LT" for "larger than" in e5a5e0a90750d66, but
that is against existing conventions, where "LT" means "less than".
Clarify by using "GT" for "greater than" in macro name, and add a missing
comment at the top of instr_time.h to note the macro's existence.
Reported by: Peter Smith <smithpb2250@gmail.com>
Author: Lukas Fittl <lukas@fittl.com> Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CAHut%2BPut94CTpjQsqOJHdHkgJ2ZXq%2BqVSfMEcmDKLiWLW-hPfA%40mail.gmail.com
Andrew Dunstan [Mon, 23 Feb 2026 20:08:55 +0000 (15:08 -0500)]
Add non-text output formats to pg_dumpall
pg_dumpall can now produce output in custom, directory, or tar formats
in addition to plain text SQL scripts. When using non-text formats,
pg_dumpall creates a directory containing:
- toc.glo: global data (roles and tablespaces) in custom format
- map.dat: mapping between database OIDs and names
- databases/: subdirectory with per-database archives named by OID
pg_restore is extended to handle these pg_dumpall archives, restoring
globals and then each database. The --globals-only option can be used
to restore only the global objects.
This enables parallel restore of pg_dumpall output and selective
restoration of individual databases from a cluster-wide backup.
Noah Misch [Thu, 26 Feb 2026 02:13:22 +0000 (18:13 -0800)]
EUC_CN, EUC_JP, EUC_KR, EUC_TW: Skip U+00A0 tests instead of failing.
Settings that ran the new test euc_kr.sql to completion would fail these
older src/pl tests. Use alternative expected outputs, for which psql
\gset and \if have reduced the maintenance burden. This fixes
"LANG=ko_KR.euckr LC_MESSAGES=C make check-world". (LC_MESSAGES=C fixes
IO::Pty usage in tests 010_tab_completion and 001_password.) That file
is new in commit c67bef3f3252a3a38bf347f9f119944176a796ce. Back-patch
to v14, like that commit.
Fujii Masao [Thu, 26 Feb 2026 00:01:52 +0000 (09:01 +0900)]
doc: Clarify INCLUDING COMMENTS behavior in CREATE TABLE LIKE.
The documentation for the INCLUDING COMMENTS option of the LIKE clause
in CREATE TABLE was inaccurate and incomplete. It stated that comments for
copied columns, constraints, and indexes are copied, but regarding comments
on constraints in reality only comments on CHECK and NOT NULL constraints
are copied; comments on other constraints (such as primary keys) are not.
In addition, comments on extended statistics are copied, but this was not
documented.
The CREATE FOREIGN TABLE documentation had a similar omission: comments
on extended statistics are also copied, but this was not mentioned.
This commit updates the documentation to clarify the actual behavior.
The CREATE TABLE reference now specifies that comments on copied columns,
CHECK constraints, NOT NULL constraints, indexes, and extended statistics are
copied. The CREATE FOREIGN TABLE reference now notes that comments on
extended statistics are copied as well.
Backpatch to all supported versions. Documentation updates related to
CREATE FOREIGN TABLE LIKE and NOT NULL constraint comment copying are
not applied to v17 and earlier, since those features were introduced in v18.
Fujii Masao [Wed, 25 Feb 2026 23:46:12 +0000 (08:46 +0900)]
Fix ProcWakeup() resetting wrong waitStart field.
Previously, when one process woke another that was waiting on a lock,
ProcWakeup() incorrectly cleared its own waitStart field (i.e.,
MyProc->waitStart) instead of that of the process being awakened.
As a result, the awakened process retained a stale lock-wait start timestamp.
This did not cause user-visible issues. pg_locks.waitstart was reported as
NULL for the awakened process (i.e., when pg_locks.granted is true),
regardless of the waitStart value.
Tom Lane [Wed, 25 Feb 2026 15:51:42 +0000 (10:51 -0500)]
Stabilize output of new isolation test insert-conflict-do-update-4.
The test added by commit 4b760a181 assumed that a table's physical
row order would be predictable after an UPDATE. But a non-heap table
AM might produce some other order. Even with heap AM, the assumption
seems risky; compare a3fd53bab for instance. Adding an ORDER BY is
cheap insurance and doesn't break any goal of the test.
Author: Pavel Borisov <pashkin.elfe@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CALT9ZEHcE6tpvumScYPO6pGk_ASjTjWojLkodHnk33dvRPHXVw@mail.gmail.com
Backpatch-through: 14
Richard Guo [Wed, 25 Feb 2026 02:13:21 +0000 (11:13 +0900)]
Fix unsafe RTE_GROUP removal in simplify_EXISTS_query
When simplify_EXISTS_query removes the GROUP BY clauses from an EXISTS
subquery, it previously deleted the RTE_GROUP RTE directly from the
subquery's range table.
This approach is dangerous because deleting an RTE from the middle of
the rtable list shifts the index of any subsequent RTE, which can
silently corrupt any Var nodes in the query tree that reference those
later relations. (Currently, this direct removal has not caused
problems because the RTE_GROUP RTE happens to always be the last entry
in the rtable list. However, relying on that is extremely fragile and
seems like trouble waiting to happen.)
Instead of deleting the RTE_GROUP RTE, this patch converts it in-place
to be RTE_RESULT type and clears its groupexprs list. This preserves
the length and indexing of the rtable list, ensuring all Var
references remain intact.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/3472344.1771858107@sss.pgh.pa.us
Backpatch-through: 18
John Naylor [Wed, 25 Feb 2026 01:44:59 +0000 (08:44 +0700)]
Fix USE_SLICING_BY_8_CRC32C builds on x86
A future commit will move the CRC function choosing logic to the
file where the hardware-specific functions are defined, but until
then add guards for builds without those functions. Oversight in
commit b9278871f.
Per buildfarm animal rhinoceros
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/4014992.1771963187@sss.pgh.pa.us
Jacob Champion [Tue, 24 Feb 2026 22:01:37 +0000 (14:01 -0800)]
pg_upgrade: Use max_protocol_version=3.0 for older servers
The grease patch in 4966bd3ed found its first problem: prior to the
February 2018 patch releases, no server knew how to negotiate protocol
versions, so pg_upgrade needs to take that into account when speaking to
those older servers.
This will be true even after the grease feature is reverted; we don't
need anyone to trip over this again in the future. Backpatch so that all
supported versions of pg_upgrade can gracefully handle an update to the
default protocol version. (This is needed for any distributions that
link older binaries against newer libpqs, such as Debian.) Branches
prior to 18 need an additional version check, for the existence of
max_protocol_version.
Per buildfarm member crake.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAOYmi%2B%3D4QhCjssfNEoZVK8LPtWxnfkwT5p-PAeoxtG9gpNjqOQ%40mail.gmail.com
Backpatch-through: 14
Álvaro Herrera [Tue, 24 Feb 2026 16:34:56 +0000 (17:34 +0100)]
Add backtrace support for Windows using DbgHelp API
Previously, backtrace generation on Windows would return an "unsupported"
message. With this commit, we rely on CaptureStackBackTrace() to capture
the call stack and the DbgHelp API (SymFromAddrW, SymGetLineFromAddrW64)
for symbol resolution.
Symbol handler initialization (SymInitialize) is performed once per
process and cached. If initialization fails, the report for it is
returned as the backtrace output. The symbol handler is cleaned up via
on_proc_exit() to release DbgHelp resources.
The implementation provides symbol names, offsets, and addresses. When
PDB files are available, it also includes source file names and line
numbers. Symbol names and file paths are converted from UTF-16 to the
database encoding using wchar2char(), which properly handles both UTF-8
and non-UTF-8 databases on Windows. When symbol information is
unavailable or encoding conversion fails, it falls back to displaying raw
addresses.
The implementation uses the explicit UTF16 versions of the DbgHelp
functions (SYMBOL_INFOW, SymFromAddrW, IMAGEHLP_LINEW64,
SymGetLineFromAddrW64) rather than the generic versions. This allows us
to rely on predictable encoding conversion, rather than using the
haphazard ANSI codepage that we'd get otherwise.
DbgHelp is apparently available on all Windows platforms we support, so
there are no version number checks.
Author: Bryan Green <dbryan.green@gmail.com> Reviewed-by: Euler Taveira <euler@eulerto.com> Reviewed-by: Jakub Wartak <jakub.wartak@enterprisedb.com> Reviewed-by: Greg Burd <greg@burd.me>
Discussion: https://postgr.es/m/a692c0fe-caca-4c08-9c5d-debfd0ef2504@gmail.com
Peter Eisentraut [Tue, 24 Feb 2026 09:56:17 +0000 (10:56 +0100)]
Make ALTER DOMAIN VALIDATE CONSTRAINT no-op when constraint is already validated
Currently, AlterDomainValidateConstraint will re-validate a constraint
that has already been validated, which would just waste cycles. This
operation should be a no-op when the constraint is already validated.
This also aligns with ATExecValidateConstraint.
Author: jian he <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CACJufxG=-Dv9fPJHqkA9c-wGZ2dDOWOXSp-X-0K_G7r-DgaASw@mail.gmail.com
Peter Eisentraut [Tue, 24 Feb 2026 09:30:50 +0000 (10:30 +0100)]
Allow ALTER COLUMN SET EXPRESSION on virtual columns with CHECK constraints
Previously, changing the generation expression of a virtual column was
prohibited if the column was referenced by a CHECK constraint. This
lifts that restriction.
RememberAllDependentForRebuilding within ATExecSetExpression will
rebuild all the dependent constraints, later ATPostAlterTypeCleanup
queues the required AlterTableStmt operations for ALTER TABLE Phase 3
execution.
Overall, ALTER COLUMN SET EXPRESSION on virtual columns may require
scanning the table to re-verify any associated CHECK constraints, but
it does not require a table rewrite in ALTER TABLE Phase 3.
Author: jian he <jian.universality@gmail.com> Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Discussion: https://postgr.es/m/CACJufxH3VETr7orF5rW29GnDk3n1wWbOE3WdkHYd3iPGrQ9E_A@mail.gmail.com
Michael Paquier [Tue, 24 Feb 2026 04:26:37 +0000 (13:26 +0900)]
Fix variety of typos and grammar mistakes
This commit includes a batch of fixes for various minor typos and
grammar mistakes, that have been proposed to the hackers mailing list
since the beginning of January.
Similar batches are planned on a bi-monthly basis depending on the
amount received, with the next one for the end of April.
Michael Paquier [Tue, 24 Feb 2026 03:54:23 +0000 (12:54 +0900)]
doc: Adjust some markups on pg_waldump page
Author: Peter Smith <smithpb2250@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://postgr.es/m/CAHut+PuuPps9bUPvouU5dH=tOTiF8QBzQox5O7DqXeOFdda79Q@mail.gmail.com
Michael Paquier [Tue, 24 Feb 2026 03:34:42 +0000 (12:34 +0900)]
fe_utils: Sprinkle some pg_malloc_object() and pg_malloc_array()
The idea is to encourage more the use of these allocation routines
across the tree, as these offer stronger type safety guarantees than
pg_malloc() & friends (type cast in the result, sizeof() embedded).
This commit updates some code paths of src/fe_utils/.
Author: Henrik TJ <henrik@0x48.dk> Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://postgr.es/m/6df1b64e-1314-9afd-41a3-3fefb76225e1@0x48.dk
Nathan Bossart [Mon, 23 Feb 2026 20:55:21 +0000 (14:55 -0600)]
Allow pg_{read,write}_all_data to access large objects.
Since the initial goal of pg_read_all_data was to be able to run
pg_dump as a non-superuser without explicitly granting access to
every object, it follows that it should allow reading all large
objects. For consistency, pg_write_all_data should allow writing
all large objects, too.
Tom Lane [Mon, 23 Feb 2026 20:30:44 +0000 (15:30 -0500)]
Work around lgamma(NaN) bug on AIX.
lgamma(NaN) should produce NaN, but on older versions of AIX
it reports an ERANGE error. While that's been fixed in the latest
version of libm, it'll take awhile for the fix to propagate. This
workaround is harmless even when the underlying bug does get fixed.
Peter Eisentraut [Mon, 23 Feb 2026 20:17:06 +0000 (21:17 +0100)]
Use LOCKMODE in parse_relation.c/.h
There were a couple of comments in parse_relation.c
> Note: properly, lockmode should be declared LOCKMODE not int, but that
> would require importing storage/lock.h into parse_relation.h. Since
> LOCKMODE is typedef'd as int anyway, that seems like overkill.
but actually LOCKMODE has been in storage/lockdefs.h for a while,
which is intentionally a more narrow header. So we can include that
one in parse_relation.h and just use LOCKMODE normally.
An alternative would be to add a duplicate typedef into
parse_relation.h, but that doesn't seem necessary here.
Reviewed-by: Andreas Karlsson <andreas@proxel.se> Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/4bcd65fb-2497-484c-bb41-83cb435eb64d%40eisentraut.org
Jacob Champion [Mon, 23 Feb 2026 18:48:20 +0000 (10:48 -0800)]
libpq: Grease the protocol by default
Send PG_PROTOCOL_GREASE and _pq_.test_protocol_negotiation, which were
introduced in commit d8d7c5dc8, by default, and fail the connection if
the server attempts to claim support for them. The hope is to provide
feedback to noncompliant implementations and gain confidence in our
ability to advance the protocol. (See the other commit for details.)
To help end users navigate the situation, a link to our documentation
that explains the behavior is displayed. We append this to the error
message when the NegotiateProtocolVersion response is incorrect, or when
the peer sends an error during startup that appears to be grease-
related.
It's still possible for users to connect to servers that don't support
protocol negotiation, by adding max_protocol_version=3.0 to their
connection strings. Only the default connection behavior is impacted.
This commit is tracked as a PG19 open item and will be reverted before
RC1. (The implementation here doesn't handle negotiation with later
server versions, so it can't be released into the wild as a
five-year-supported feature. But an improved implementation might be
able to do so, in the future...)
Author: Jelte Fennema-Nio <postgres@jeltef.nl> Co-authored-by: Jacob Champion <jacob.champion@enterprisedb.com>
Discussion: https://postgr.es/m/DDPR5BPWH1RJ.1LWAK6QAURVAY%40jeltef.nl
Tom Lane [Mon, 23 Feb 2026 18:34:22 +0000 (13:34 -0500)]
Restore AIX support.
The concerns that led us to remove AIX support in commit 0b16bb877
have now been alleviated:
1. IBM has stepped forward to provide support, including buildfarm
animal(s).
2. AIX 7.2 and later seem to be fine with large pg_attribute_aligned
requirements. Since 7.1 is now EOL anyway, we can just cease to
support it.
3. Tossing xlc support overboard seems okay as well. It's a bit
sad to drop one of the few remaining non-gcc-alike compilers, but
working around xlc's bugs and idiosyncrasies doesn't seem justified
by the theoretical portability benefits.
4. Likewise, we can stop supporting 32-bit AIX builds. This is
not so much about whether we could build such executables as that
they're too much of a pain to manage in the field, due to limited
address space available for dynamic library loading.
5. We hit on a way to manage catalog column alignment that doesn't
require continuing developer effort (see commit ecae09725).
Hence, this commit reverts 0b16bb877 and some follow-on commits
such as e6bb491bf, except for not putting back XLC support nor
the changes related to catalog column alignment.
Some other notable changes from the way things were in v16:
Prefer unnamed POSIX semaphores on AIX, rather than the default
choice of SysV semaphores.
Include /opt/freeware/lib in -Wl,-blibpath, even when it is not
mentioned anywhere in LDFLAGS.
Remove platform-specific adjustment of MEMSET_LOOP_LIMIT; maybe
that's still the right thing, but it really ought to be re-tested.
Silence compiler warnings related to getpeereid(), wcstombs_l(),
and PAM conversation procs.
Accept "libpythonXXX.a" as an okay name for the Python shared
library (but only on AIX!).
Author: Aditya Kamath <Aditya.Kamath1@ibm.com>
Author: Srirama Kucherlapati <sriram.rk@in.ibm.com> Co-authored-by: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CY5PR11MB63928CC05906F27FB10D74D0FD322@CY5PR11MB6392.namprd11.prod.outlook.com
Tom Lane [Mon, 23 Feb 2026 17:34:51 +0000 (12:34 -0500)]
Cope with AIX's alignment woes by using _Pragma("pack").
Because we assume that int64 and double have the same alignment
requirement, AIX's default behavior that alignof(double) = 4 while
alignof(int64) = 8 is a headache. There are two issues:
1. We align both int8 and float8 tuple columns per ALIGNOF_DOUBLE,
which is an ancient choice that can't be undone without breaking
pg_upgrade and creating some subtle SQL-level compatibility issues
too. However, the cost of that is just some marginal inefficiency
in fetching int8 values, which can't be too awful if the platform
architects were willing to pay the same costs for fetching float8s.
So our decision is to leave that alone. This patch makes our
alignment choices the same as they were pre-v17, namely that
ALIGNOF_DOUBLE and ALIGNOF_INT64_T are whatever the compiler prefers
and then MAXIMUM_ALIGNOF is the larger of the two. (On all supported
platforms other than AIX, all three values will be the same.)
2. We need to overlay C structs onto catalog tuples, and int8 fields
in those struct declarations may not be aligned to match this rule.
In the old branches we had some annoying rules about ordering catalog
columns to avoid alignment problems, but nobody wants to resurrect
those. However, there's a better answer: make the compiler construe
those struct declarations the way we need it to by using the pack(N)
pragma. This requires no manual effort to maintain going forward;
we only have to insert the pragma into all the catalog *.h files.
(As the catalogs stand at this writing, nothing actually changes
because we've not moved any affected columns since v16; hence no
catversion bump is required. The point of this is to not have
to worry about the issue going forward.)
We did not have this option when the AIX port was first made. This
patch depends on the C99 feature _Pragma(), as well as the pack(N)
pragma which dates to somewhere around gcc 4.0, and probably doesn't
exist in xlc at all. But now that we've agreed to toss xlc support
out the window, there doesn't seem to be a reason not to go this way.
In passing, I got rid of LONGALIGN[_DOWN] along with the configure
probes for ALIGNOF_LONG. We were not using those anywhere and it
seems highly unlikely that we'd do so in future. Instead supply
INT64ALIGN[_DOWN], which isn't used either but at least could
have a good reason to be used.
Nathan Bossart [Mon, 23 Feb 2026 17:22:04 +0000 (11:22 -0600)]
Warn upon successful MD5 password authentication.
This uses the "connection warning" infrastructure introduced by
commit 1d92e0c2cc to emit a WARNING when an MD5 password is used to
authenticate. MD5 password support was marked as deprecated in
v18 and will be removed in a future release of Postgres. These
warnings are on by default but can be turned off via the existing
md5_password_warnings parameter.
Reviewed-by: Andreas Karlsson <andreas@proxel.se> Reviewed-by: Xiangyu Liang <liangxiangyu_2013@163.com>
Discussion: https://postgr.es/m/aYzeAYEbodkkg5e-%40nathan
Peter Eisentraut [Mon, 23 Feb 2026 16:38:06 +0000 (17:38 +0100)]
Rename validate_relation_kind()
There are three static definitions of validate_relation_kind() in the
codebase, one each in table.c, indexam.c and sequence.c, validating that
the given relation is a table, an index or a sequence respectively.
The compiler knows which definition to use where because they are static.
But this could be confusing to a reader. Rename these functions so that
their names reflect the kind of relation they are validating. While at
it, also update the comments in table.c to clarify the definition of
table-like relkinds so that we don't have to maintain the exclusion list
as the set of relkinds undergoes changes.
Peter Eisentraut [Mon, 23 Feb 2026 16:26:29 +0000 (17:26 +0100)]
Flip logic in table validate_relation_kind
It instead of checking which relkinds it shouldn't be, explicitly list
the ones we accept. This is used to check which relkinds are accepted
in table_open() and related functions. Before this change, figuring
that out was always a few steps too complicated. This also makes
changes for new relkinds more explicit instead of accidental.
Finally, this makes this more aligned with the functions of the same
name in src/backend/access/index/indexam.c and
src/backend/access/sequence/sequence.c.
Andrew Dunstan [Sat, 21 Feb 2026 22:17:48 +0000 (17:17 -0500)]
Disallow CR and LF in database, role, and tablespace names
Previously, these characters could cause problems when passed through
shell commands, and were flagged with a comment in string_utils.c
suggesting they be rejected in a future major release.
The affected commands are CREATE DATABASE, CREATE ROLE, CREATE TABLESPACE,
ALTER DATABASE RENAME, ALTER ROLE RENAME, and ALTER TABLESPACE RENAME.
Also add a pg_upgrade check to detect these invalid names in clusters
being upgraded from pre-v19 versions, producing a report file listing
any offending objects that must be renamed before upgrading.
Tests have been modified accordingly.
Author: Mahendra Singh Thalor <mahi6run@gmail.com> Reviewed-By: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-By: Andrew Dunstan <andrew@dunslane.net> Reviewed-By: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-By: Nathan Bossart <nathandbossart@gmail.com> Reviewed-By: Srinath Reddy <srinath2133@gmail.com>
Discussion: https://postgr.es/m/CAKYtNApkOi4FY0S7+3jpTqnHVyyZ6Tbzhtbah-NBbY-mGsiKAQ@mail.gmail.com
Peter Eisentraut [Mon, 23 Feb 2026 15:25:54 +0000 (16:25 +0100)]
meson: allow disabling building/installation of static libraries.
We now support the common meson option -Ddefault_library, with values
'both' (the default), 'shared' (install only shared libraries), and
'static' (install only static libraries). The 'static' choice doesn't
actually work, since psql and other programs insist on linking to the
shared version of libpq, but it's there pro-forma. It could be built
out if we really wanted, but since we have never supported the
equivalent in the autoconf build system, there doesn't appear to be an
urgent need.
With an eye to re-supporting AIX, the internal implementation
distinguishes whether to install libpgport.a and other static-only
libraries from whether to build/install the static variant of
libraries that we can build both ways. This detail isn't exposed as a
meson option, though it could be if there's demand.
The Cirrus CI task SanityCheck now uses -Ddefault_library=shared to
save a little bit of build time (and to test this option).
Author: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/e8aa97db-872b-4087-b073-f296baae948d@eisentraut.org
Nathan Bossart [Mon, 23 Feb 2026 15:26:00 +0000 (09:26 -0600)]
Make use of pg_popcount() in more places.
This replaces some loops over word-length popcount functions with
calls to pg_popcount(). Since pg_popcount() may use a function
pointer for inputs with sizes >= a Bitmapset word, this produces a
small regression for the common one-word case in bms_num_members().
To deal with that, this commit adds an inlined fast-path for that
case. This fast-path could arguably go in pg_popcount() itself
(with an appropriate alignment check), but that is left for future
study.
Suggested-by: John Naylor <johncnaylorls@gmail.com> Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/CANWCAZY7R%2Biy%2Br9YM_sySNydHzNqUirx1xk0tB3ej5HO62GdgQ%40mail.gmail.com
Nathan Bossart [Mon, 23 Feb 2026 15:26:00 +0000 (09:26 -0600)]
Remove uses of popcount builtins.
This commit replaces the implementations of pg_popcount{32,64} with
branchless ones in plain C. While these new implementations do not
make use of more sophisticated population count instructions
available on some CPUs, testing indicates they perform well,
especially now that they are inlined. Newer versions of popular
compilers will automatically replace these with special
instructions if possible, anyway. A follow-up commit will replace
various loops over these functions with calls to pg_popcount(),
leaving us little reason to worry about micro-optimizing them
further.
Since this commit removes the only uses of the popcount builtins,
we can also remove the corresponding configuration checks.
Suggested-by: John Naylor <johncnaylorls@gmail.com> Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/CANWCAZY7R%2Biy%2Br9YM_sySNydHzNqUirx1xk0tB3ej5HO62GdgQ%40mail.gmail.com
John Naylor [Mon, 23 Feb 2026 12:19:49 +0000 (19:19 +0700)]
Rename pg_crc32c_sse42_choose.c for general purpose
Future commits will consolidate the CPU feature detection functionality
now scattered around in various files, and the CRC "*_choose.c"
files seem to be the natural place for it. For now, just rename in
a separate commit to make it easier to follow the git log. Do the
minimum necessary to keep the build systems functional, and build the
new file pg_cpu_x86.c unconditionally using guards to control the
visibility of its contents, following the model of some more recent
files in src/port.
Limit scope to x86 to reduce the number of moving parts, since the
motivation for doing this now is to clear out some technical debt
before adding AVX2 detection. Arm is left for future work.
Peter Eisentraut [Mon, 23 Feb 2026 09:56:54 +0000 (10:56 +0100)]
Change error message for sequence validate_relation_kind()
We can just say "... is not a sequence" instead of the more
complicated variant from before, which was probably copied from
src/backend/access/table/table.c.
Peter Eisentraut [Mon, 23 Feb 2026 09:37:38 +0000 (10:37 +0100)]
meson: Refactor libpq targets variables
Some of the knowledge of the libpq targets was spread around between
the top-level meson.build and src/interfaces/libpq*. This change
organizes it more like other targets by having a libpq_targets
variable that different subdirectories can add to.
Peter Eisentraut [Mon, 23 Feb 2026 06:37:50 +0000 (07:37 +0100)]
Enable -Wimplicit-fallthrough option for clang
On clang, -Wimplicit-fallthrough requires annotations with attributes,
but on gcc, -Wimplicit-fallthrough is the same as
-Wimplicit-fallthrough=3, which allows annotations with comments. In
order to enforce consistent annotations with attributes on both
compilers, we test first for -Wimplicit-fallthrough=5, which will
succeed on gcc, and if that is not found we test for
-Wimplicit-fallthrough.
Peter Eisentraut [Mon, 23 Feb 2026 06:37:50 +0000 (07:37 +0100)]
Fix additional fallthrough warnings from clang
Clang warns if falling through to a case or default label that is
immediately followed by break, but GCC does
not (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91432). (MSVC also
warns about the equivalent code in C++.)
This is in preparation for enabling fallthrough warnings on Clang.
Amit Kapila [Mon, 23 Feb 2026 04:49:05 +0000 (10:19 +0530)]
Avoid including utils/timestamp.h in conflict.h.
conflict.h currently includes utils/timestamp.h despite only requiring
basic timestamp type definitions. This creates unnecessary overhead.
Replace the include with datatype/timestamp.h to provide the necessary
types. This change requires explicitly including utils/timestamp.h in
test_custom_fixed_stats.c, which previously relied on the indirect
inclusion.
Extracted from the larger patch by Andres Freund.
Discussion: https://postgr.es/m/aY-UE-4t7FiYgH3t@alap3.anarazel.de
Michael Paquier [Mon, 23 Feb 2026 04:42:38 +0000 (13:42 +0900)]
doc: Add section "Options" for pg_controldata
Adding this section brings consistency with the pages of other tools,
potentially easing the introduction of new options in the future as
these are now showing in the shape of a list.
Author: Peter Smith <smithpb2250@gmail.com> Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://postgr.es/m/CAHut+PtSF5AW3DHpYA-_muDLms2xBUzHpd545snVj8vFpmsmGg@mail.gmail.com
On common architectures, the PGPROC struct happened to be a multiple
of 64 bytes on PG 18, but it's changed on 'master' since. There was
worry that changing the alignment might hurt performance, due to false
cacheline sharing across elements in the proc array. However, there
was no explicit alignment, so any alignment to cache lines was
accidental. Add explicit alignment to remove worry about false
sharing.
The ordering was pretty random, making it hard to get an overview of
what's in it. Group related fields together, and add comments to act
as separators between the groups.
Michael Paquier [Sun, 22 Feb 2026 06:12:58 +0000 (15:12 +0900)]
doc: Add description of "filename" for pg_walsummary
This command requires an input file (WAL summary file), that has to be
specified without an option name. The shape of the command and how to
use this parameter is implied in its synopsis. However, this page
lacked a description of the parameter. Listing parameters that do
not require an option is a common practice across the docs. See for
example pg_dump, pg_restore, etc.
Author: Peter Smith <smithpb2250@gmail.com>
Discussion: https://postgr.es/m/CAHut+PtbQi8Dw_0upS9dd=Oh9OqfOdAo=0_DOKG=YSRT_a+0Fw@mail.gmail.com
Álvaro Herrera [Sat, 21 Feb 2026 11:22:08 +0000 (12:22 +0100)]
Avoid name collision with NOT NULL constraints
If a CREATE TABLE statement defined a constraint whose name is identical
to the name generated for a NOT NULL constraint, we'd throw an
(unnecessary) unique key violation error on
pg_constraint_conrelid_contypid_conname_index: this can easily be
avoided by choosing a different name for the NOT NULL constraint.
Fix by passing the constraint names already created by
AddRelationNewConstraints() to AddRelationNotNullConstraints(), so that
the latter can avoid name collisions with them.
Bug: #19393
Author: Laurenz Albe <laurenz.albe@cybertec.at> Reported-by: Hüseyin Demir <huseyin.d3r@gmail.com>
Backpatch-through: 18
Discussion: https://postgr.es/m/19393-6a82427485a744cf@postgresql.org
The field was mainly used for the position in a LOCK's wait queue, but
also as the position in a the freelist when the PGPROC entry was not
in use. The reuse saves some memory at the expense of readability,
which seems like a bad tradeoff. If we wanted to make the struct
smaller there's other things we could do, but we're actually just
discussing adding padding to the struct for performance reasons.
Nathan Bossart [Fri, 20 Feb 2026 18:07:27 +0000 (12:07 -0600)]
Speedup COPY FROM with additional function inlining.
Following the example set by commit 58a359e585, we can squeeze out
a little more performance from COPY FROM (FORMAT {text,csv}) by
inlining CopyReadLineText() and passing the is_csv parameter as a
constant. This allows the compiler to emit specialized code with
fewer branches.
This is preparatory work for a proposed follow-up commit that would
further optimize this code with SIMD instructions.
Author: Nazir Bilal Yavuz <byavuz81@gmail.com> Reviewed-by: Ayoub Kazar <ma_kazar@esi.dz> Tested-by: Manni Wood <manni.wood@enterprisedb.com>
Discussion: https://postgr.es/m/CAOzEurSW8cNr6TPKsjrstnPfhf4QyQqB4tnPXGGe8N4e_v7Jig%40mail.gmail.com
Fix expanding 'bounds' in pg_trgm's calc_word_similarity() function
If the 'bounds' array needs to be expanded, because the input contains
more trigrams than the initial guess, the code didn't return the
reallocated array correctly to the caller. That could lead to a crash
in the rare case that the input string becomes longer when it's
lower-cased. The only known instance of that is when an ICU locale is
used with certain single-byte encodings. This was an oversight in
commit 00896ddaf41f.
Richard Guo [Fri, 20 Feb 2026 08:57:53 +0000 (17:57 +0900)]
Fix computation of varnullingrels when translating appendrel Var
When adjust_appendrel_attrs translates a Var referencing a parent
relation into a Var referencing a child relation, it propagates
varnullingrels from the parent Var to the translated Var. Previously,
the code simply overwrote the translated Var's varnullingrels with
those of the parent.
This was incorrect because the translated Var might already possess
nonempty varnullingrels. This happens, for example, when a LATERAL
subquery within a UNION ALL references a Var from the nullable side of
an outer join. In such cases, the translated Var correctly carries
the outer join's relid in its varnullingrels. Overwriting these bits
with the parent Var's set caused the planner to lose track of the fact
that the Var could be nulled by that outer join.
In the reported case, because the underlying column had a NOT NULL
constraint, the planner incorrectly deduced that the Var could never
be NULL and discarded essential IS NOT NULL filters. This led to
incorrect query results where NULL rows were returned instead of being
filtered out.
To fix, use bms_add_members to merge the parent Var's varnullingrels
into the translated Var's existing set, preserving both sources of
nullability.
Back-patch to v16. Although the reported case does not seem to cause
problems in v16, leaving incorrect varnullingrels in the tree seems
like a trap for the unwary.
Bug: #19412 Reported-by: Sergey Shinderuk <s.shinderuk@postgrespro.ru>
Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/19412-1d0318089b86859e@postgresql.org
Backpatch-through: 16
Amit Kapila [Fri, 20 Feb 2026 03:56:33 +0000 (09:26 +0530)]
Avoid including worker_internal.h in pgstat.h.
pgstat.h is a widely included header. Including worker_internal.h there is
unnecessary and creates tight coupling. By refactoring
pgstat_report_subscription_error() to fetch the required
LogicalRepWorkerType internally rather than receiving it as an argument,
we can eliminate the need for the internal header.
Reported-by: Andres Freund <andres@anarazel.de>
Author: Nisha Moond <nisha.moond412@gmail.com> Reviewed-by: vignesh C <vignesh21@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Discussion: https://postgr.es/m/aY-UE-4t7FiYgH3t@alap3.anarazel.de
Nathan Bossart [Thu, 19 Feb 2026 22:19:41 +0000 (16:19 -0600)]
Remove SpinLockFree() and S_LOCK_FREE().
S_LOCK_FREE() is used by the test program in s_lock.c, but nobody
has voiced concerns about losing some coverage there.
SpinLockFree() appears to have been unused since it was introduced
by commit 499abb0c0f. There was agreement to remove these in 2020,
but it never happened. Since we still have agreement for removal
in 2026, let's do that now.
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/aZX2oUcKf7IzHnnK%40nathan
Discussion: https://postgr.es/m/20200608225338.m5zho424w6lpwb2d%40alap3.anarazel.de
Robert Haas [Thu, 19 Feb 2026 18:46:10 +0000 (13:46 -0500)]
Fix add_partial_path interaction with disabled_nodes
Commit e22253467942fdb100087787c3e1e3a8620c54b2 adjusted the logic in
add_path() to keep the path list sorted by disabled_nodes and then by
total_cost, but failed to make the corresponding adjustment to
add_partial_path. As a result, add_partial_path might sort the path list
just by total cost, which could lead to later planner misbehavior.
In principle, this should be back-patched to v18, but we are typically
reluctant to back-patch planner fixes for fear of destabilizing working
installations, and it is unclear to me that this has sufficiently
serious consequences to justify an exception, so for now, no back-patch.
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: http://postgr.es/m/CAMbWs4-mO3jMK4t_LgcJ+7Eo=NmGgkxettgRaVbJzZvVZ1koMA@mail.gmail.com
projects / thirdparty / postgresql.git / log
