Tom Lane [Mon, 11 May 2026 12:13:50 +0000 (05:13 -0700)]
Make palloc_array() and friends safe against integer overflow.
Sufficiently large "count" arguments could result in undetected
overflow, causing the allocated memory chunk to be much smaller
than what the caller will subsequently write into it. This is
unlikely to be a hazard with 64-bit size_t but can sometimes
happen on 32-bit builds, primarily where a function allocates
workspace that's significantly larger than its input data.
Rather than trying to patch the at-risk callers piecemeal,
let's just redefine these macros so that they always check.
To do that, move the longstanding add_size() and mul_size() functions
into palloc.h and mcxt.c, and adjust them to not be specific to
shared-memory allocation. Then invent palloc_mul(), palloc0_mul(),
palloc_mul_extended() to use these functions. Actually, the latter
use inlined copies to save one function call. repalloc_array() gets
similar treatment. I didn't bother trying to inline the calls for
repalloc0_array() though.
In v14 and v15, this also adds repalloc_extended(), which previously
was only available in v16 and up.
We need copies of all this in fe_memutils.[hc] as well, since that
module also provides palloc_array() etc.
Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Backpatch-through: 14
Security: CVE-2026-6473
Tom Lane [Mon, 11 May 2026 12:13:50 +0000 (05:13 -0700)]
Add pg_add_size_overflow() and friends
Commit 600086f47 added (several bespoke copies of) size_t addition with
overflow checks to libpq. Move this to common/int.h, along with
its subtraction and multiplication counterparts.
pg_neg_size_overflow() is intentionally omitted; I'm not sure we should
add SSIZE_MAX to win32_port.h for the sake of a function with no
callers.
Back-patch of commit 8934f2136, done now because pg_add_size_overflow()
and friends are needed more widely for security fixes.
Author: Jacob Champion <jacob.champion@enterprisedb.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CAOYmi%2B%3D%2BpqUd2MUitvgW1pAJuXgG_TKCVc3_Ek7pe8z9nkf%2BAg%40mail.gmail.com
Backpatch-through: 14-18
Security: CVE-2026-6473
Michael Paquier [Mon, 11 May 2026 12:13:50 +0000 (05:13 -0700)]
Fix overflows with ts_headline()
The options "StartSel", "StopSel" and "FragmentDelimiter" given by a
caller of the SQL function ts_headline() have their lengths stored as
int16. When providing values larger than PG_INT16_MAX, it was possible
to overflow the length values stored, leading to incorrect behaviors in
generateHeadline(), in most cases translating to a crash.
Attempting to use values for these options larger than PG_INT16_MAX is
now blocked. Some test cases are added to cover our tracks.
Michael Paquier [Mon, 11 May 2026 12:13:50 +0000 (05:13 -0700)]
ltree: Fix overflows with lquery parsing
The lquery parser in contrib/ltree/ had two overflow problems:
- A single lquery level with many OR-separated variants (e.g.,
'label1|label2|...'), could cause an overflow of totallen, this being
stored as a uint16, meaning a maximum value of UINT16_MAX or 65k. Each
variant contributes MAXALIGN(LVAR_HDRSIZE + len) bytes. With enough
long variants, the value would wraparound. This would corrupt the data
written by LQL_NEXT(), leading to a stack corruption, most likely
translating into a crash, but it would allow incorrect memory access.
- numvar, labelled as a uint16, counts the number of OR-variants in a
single level, and it is incremented without bounds checking. With more
than PG_UINT16_MAX (65k) variants in a single level, and a minimum of
131kB of input data, it would wrap to 0. When a (wildcard) '*' is
used, this would change the query results silently.
For both issues, a set of overflows checks are added to guard against
these problematic patterns.
The first issue has been reported by the three people listed below,
affecting v16 and newer versions due to b1665bf01e5f. Its coding was
still unsafe in v14 and v15. The second issue affects all the stable
branches; I have bumped into while reviewing the code of the module.
Reported-by: Vergissmeinnicht <vergissmeinnichtzh@gmail.com> Reported-by: A1ex <alex000young@gmail.com> Reported-by: Jihe Wang <wangjihe.mail@gmail.com>
Author: Michael Paquier <michael@paquier.xyz>
Security: CVE-2026-6473
Backpatch-through: 14
Etsuro Fujita [Tue, 5 May 2026 09:55:05 +0000 (18:55 +0900)]
postgres_fdw: Fix handling of abort-cleanup-failed connections.
As connections that failed abort cleanup can't safely be further used,
if a remote query tries to get such a connection, we reject it.
Previously, this rejection involved dropping the connection if it was
open, without accounting for the possibility of open cursors using it,
causing a server crash when such an open cursor tried to use an
already-dropped connection, as a cursor-handling function
(create_cursor, fetch_more_data, or close_cursor) was called on a freed
PGconn. To fix, delay dropping failed connections until abort cleanup
of the main transaction, to ensure open cursors using such a connection
can safely refer to the PGconn for it.
Richard Guo [Tue, 5 May 2026 01:31:17 +0000 (10:31 +0900)]
Consider collation when proving subquery uniqueness
rel_is_distinct_for()'s RTE_SUBQUERY branch passed only the equality
operator from each join clause to query_is_distinct_for(), discarding
the operator's input collation. query_is_distinct_for() then verified
opfamily compatibility but never checked collations, so a DISTINCT /
GROUP BY / set-op operating under one collation was trusted to prove
uniqueness for a comparison performed under an unrelated collation.
As with the recent fix in relation_has_unique_index_for(), this is
unsound for nondeterministic collations and yields wrong query results
in any optimization that consumes the proof.
Fix by carrying each clause's operator input collation into
query_is_distinct_for() and validating it at every check-site against
the subquery target expression's collation.
Back-patch to all supported branches. query_is_distinct_for() is
declared in an installed header, so on stable branches the existing
two-list signature is retained as a thin wrapper that forwards to a
new collation-aware entry point; external callers continue to receive
the historical collation-blind answer.
Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAMbWs4_XUUSTyzCaRjUeeahWNqi=8ZOA5Q4coi8zUVEDSBkM6A@mail.gmail.com
Backpatch-through: 14
Richard Guo [Tue, 5 May 2026 01:30:37 +0000 (10:30 +0900)]
Consider collation when proving uniqueness from unique indexes
relation_has_unique_index_for() has long had an XXX noting that it
doesn't check collations when matching a unique index's columns
against equality clauses. This was benign as long as all collations
in play reduced to the same notion of equality, but has been incorrect
since nondeterministic collations were introduced in PG 12: a unique
index under a deterministic collation does not prove uniqueness under
a nondeterministic collation, nor vice versa.
The consequence is wrong query results for any planner optimization
that consumes the faulty proof, including inner-unique join execution
(which stops the inner search after the first match per outer row),
useless-left-join removal, semijoin-to-innerjoin reduction, and
self-join elimination.
Fix by requiring the index's collation to agree on equality with the
clause's input collation. Two collations agree on equality if either
is InvalidOid (denoting a non-collation-sensitive operation, which
cannot conflict with the other side), if they have the same OID, or if
both are deterministic: by definition a deterministic collation treats
two strings as equal iff they are byte-wise equal (see CREATE
COLLATION), so any two deterministic collations share the same
equality relation and the uniqueness proof carries over. Any mismatch
involving a nondeterministic collation is rejected.
Back-patch to all supported branches; the bug has existed since
nondeterministic collations were introduced in PG 12.
Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAMbWs4_XUUSTyzCaRjUeeahWNqi=8ZOA5Q4coi8zUVEDSBkM6A@mail.gmail.com
Backpatch-through: 14
Mark modified the FSM buffer as dirty during recovery
The XLogRecordPageWithFreeSpace function updates the freespace map (FSM) data
while replaying data-level WAL records during the recovery. If the FSM block
is updated, it needs to be marked as modified. Currently, this is done with
the MarkBufferDirtyHint call (as in all other cases for modifying FSM data).
However, in the recovery context, this function will actually do nothing if
checksums are enabled. It's assumed that the page should not be dirtied
during recovery while modifying hints to protect against torn pages, since no
new WAL data can be generated at this point to store FPI.
Such logic does not seem fully aligned with the FSM case, as its blocks could
be simply zeroed if a checksum mismatch is detected. Currently, changes to an
FSM block could be lost if each change to that block occurs infrequently
enough to allow it to be evicted from the cache. To persist the change, the
modification needs to be performed while the FSM block is still kept in
buffers and marked as dirty after receiving its FPI. If the block has already
been cleaned, the change won't be persisted, so stored FSM blocks may remain
in an obsolete state.
If a large number of discrepancies between the data in leaf FSM blocks and the
actual data blocks accumulate on the replica server, this could cause
significant delays in insert operations after switchover. Such an insert
operation may need to visit many data blocks marked as having sufficient
space in the FSM, only to discover that the information is incorrect and the
FSM records need to be corrected. In a heavily trafficked insert-only table
with many concurrent clients performing inserts, this has been observed to
cause several-second stalls, causing visible application malfunction. The
desire to avoid such cases was the reason behind the commit ab7dbd681, which
introduced an update of FSM data during the heap_xlog_visible invocation.
However, an update to the FSM data on the standby side could be lost due to a
missing 'dirty' flag, so there is still a possibility that a large number of
FSM records will contain incorrect data. Note that having a zeroed FSM page
in such a case (due to a checksum mismatch) is preferable, as a zero value
will be interpreted as an indication of full data blocks, and the inserter
will be routed to the next FSM block or to the end of the table.
Given that FSM is ready to handle torn page writes and
XLogRecordPageWithFreeSpace is called only during the recovery, there seems
to be no reason to use MarkBufferDirtyHint here instead of a regular
MarkBufferDirty call.
Andrew Dunstan [Fri, 1 May 2026 19:12:28 +0000 (15:12 -0400)]
Add missing connection validation in ECPG
ECPGdeallocate_all(), ECPGprepared_statement(), ECPGget_desc(), and
ecpg_freeStmtCacheEntry() could crash with a SIGSEGV when called
without an established connection (for example, when EXEC SQL CONNECT
was forgotten or a non-existent connection name was used), because
they dereferenced the result of ecpg_get_connection() without first
checking it for NULL.
Each site is fixed in the style of the surrounding code.
Michael Paquier [Fri, 1 May 2026 04:10:48 +0000 (13:10 +0900)]
doc: Mention validation attempt during ALTER INDEX .. ATTACH PARTITION
Since 9d3e094f12, the command tries to validate the parent index of the
named index, if invalid. The documentation did not mention this
behavior, which could be confusing.
Author: Mohamed ALi <moali.pg@gmail.com>
Discussion: https://postgr.es/m/CAGnOmWpHu25_LpT=zv7KtetQhqV1QEZzFYLd_TDyOLu1Od9fpw@mail.gmail.com
Backpatch-through: 14
Andrew Dunstan [Thu, 30 Apr 2026 15:04:57 +0000 (11:04 -0400)]
Fix attnum remapping in generateClonedExtStatsStmt()
When cloning extended statistics via CREATE TABLE ... LIKE ... INCLUDING
STATISTICS, stxkeys holds attribute numbers from the source (parent)
table, but get_attname() was being called with the child relation's
OID. If the parent has dropped columns, the child's attribute numbers
are renumbered sequentially and no longer match, so the lookup either
returns the wrong column name (silent corruption) or errors out when
the attnum does not exist in the child.
Fix it by remapping the parent attnum through attmap before the lookup,
consistent with how expression statistics are already handled a few
lines below.
Add a regression test covering both manifestations: a 3-column parent
where the stale attnum refers to no child column (cache-lookup error),
and a 4-column parent where the stale attnum silently refers to the
wrong child column.
Suppress "has no symbols" linker warnings on macOS.
After a recent macOS update, building Postgres produces warnings
that look like this:
ranlib: warning: 'libpgport_shlib.a(pg_cpu_x86.c.o)' has no symbols
ranlib: warning: 'libpgport_shlib.a(pg_popcount_x86.c.o)' has no symbols
To fix, add a dummy symbol to files that may otherwise have none.
Per project policy, this is a candidate for back-patching into
out-of-support branches: it suppresses annoying compiler warnings
but changes no behavior.
Reported-by: Zhang Mingli <zmlpostgres@gmail.com> Reviewed-by: John Naylor <johncnaylorls@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/229aaaf3-f529-44ed-8e50-00cb6909af21%40Spark
Backpatch-through: 13
Michael Paquier [Mon, 27 Apr 2026 07:17:29 +0000 (16:17 +0900)]
doc: Fix grammar in some logical replication pages
Author: Peter Smith <smithpb2250@gmail.com>
Discussion: https://postgr.es/m/CAHut+PuvY_wYLPJ4DTs7NE9Lu2ty4d-OgZAOJC-NvCM=2wwcQQ@mail.gmail.com
Backpatch-through: 14
Tom Lane [Fri, 24 Apr 2026 16:28:35 +0000 (12:28 -0400)]
Update time zone data files to tzdata release 2026b.
British Columbia (America/Vancouver) moved to permanent UTC-07 on
2026-03-09, which will affect their clocks beginning on 2026-11-01.
For lack of any clarity on the point, assume their TZ abbreviation
will be MST from that time forward.
Moldova (Europe/Chisinau) has followed EU DST transition times since
2022.
David Rowley [Fri, 24 Apr 2026 02:04:55 +0000 (14:04 +1200)]
Fix incorrect logic for hashed IN / NOT IN with non-strict operators
ExecEvalHashedScalarArrayOp(), when using a strict equality function,
performs a short-circuit when looking up NULL values. When the function
is non-strict, the code incorrectly looked up the hash table for a
zero-valued Datum, which could have resulted in an accidental true
return if the hash table contained zero valued Datum, or could result
in a crash for non-byval types.
Here we fix this by adding an extra step when we build the hash table to
check what the result of a NULL lookup would be. This requires looping
over the array and checking what the non-hashed version of the code
would do. We cache the results of that in the expression so that we can
reuse the result any time we're asked to search for a NULL value.
It's important to note that non-strict equality functions are free to
treat any NULL value as equal to any non-NULL value. For example,
someone may wish to design a type that treats an empty string and NULL
as equal.
All built-in types have strict equality functions, so this could affect
custom / user-defined types.
Author: Chengpeng Yan <chengpeng_yan@outlook.com>
Author: David Rowley <dgrowleyml@gmail.com> Reviewed-by: ChangAo Chen <cca5507@qq.com>
Discussion: https://postgr.es/m/A16187AE-2359-4265-9F5E-71D015EC2B2D@outlook.com
Backpatch-through: 14
pg_test_timing: fix unit in backward-clock warning
pg_test_timing reports timing differences in nanoseconds in master, and
in microseconds in v14 through v18, but previously the backward-clock
warning incorrectly labeled the value as milliseconds.
This commit fixes the warning message to use "ns" in master and
"us" in v14 through v18, matching the actual unit being reported.
Backpatch to all supported versions.
Author: Chao Li <lic@highgo.com> Reviewed-by: Lukas Fittl <lukas@fittl.com> Reviewed-by: Xiaopeng Wang <wxp_728@163.com> Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/F780CEEB-A237-4302-9F55-60E9D8B6533D@gmail.com
Backpatch-through: 14
Don't call CheckAttributeType() with InvalidOid on dropped cols
If CheckAttributeType() is called with InvalidOid, it performs a bunch
of pointless, futile syscache lookups with InvalidOid, but ultimately
tolerates it and has no effect. We were calling it with InvalidOid on
dropped columns, but it seems accidental that it works, so let's stop
doing it.
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/93ce56cd-02a6-4db1-8224-c8999372facc@iki.fi
Backpatch-through: 14
Don't allow composite type to be member of itself via multirange
CheckAttributeType() checks that a composite type is not made a member
of itself with ALTER TABLE ADD COLUMN or ALTER TYPE ADD ATTRIBUTE,
even indirectly via a domain, array, another composite type or a range
type. But it missed checking for multiranges. That was a simple
oversight when multiranges were added.
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/93ce56cd-02a6-4db1-8224-c8999372facc@iki.fi
Backpatch-through: 14
Tom Lane [Wed, 22 Apr 2026 16:41:01 +0000 (12:41 -0400)]
Guard against overly-long numeric formatting symbols from locale.
to_char() allocates its output buffer with 8 bytes per formatting
code in the pattern. If the locale's currency symbol, thousands
separator, or decimal or sign symbol is more than 8 bytes long,
in principle we could overrun the output buffer. No such locales
exist in the real world, so it seems sufficient to truncate the
symbol if we do see it's too long.
Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/638232.1776790821@sss.pgh.pa.us
Backpatch-through: 14
Tom Lane [Wed, 22 Apr 2026 16:02:15 +0000 (12:02 -0400)]
Prevent some buffer overruns in spell.c's parsing of affix files.
parse_affentry() and addCompoundAffixFlagValue() each collect fields
from an affix file into working buffers of size BUFSIZ. They failed
to defend against overlength fields, so that a malicious affix file
could cause a stack smash. BUFSIZ (typically 8K) is certainly way
longer than any reasonable affix field, but let's fix this while
we're closing holes in this area.
I chose to do this by silently truncating the input before it can
overrun the buffer, using logic comparable to the existing logic in
get_nextfield(). Certainly there's at least as good an argument for
raising an error, but for now let's follow the existing precedent.
Reported-by: Igor Stepansky <igor.stepansky@orca.security>
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/864123.1776810909@sss.pgh.pa.us
Backpatch-through: 14
Tom Lane [Wed, 22 Apr 2026 14:47:56 +0000 (10:47 -0400)]
Prevent buffer overrun in spell.c's CheckAffix().
This function writes into a caller-supplied buffer of length
2 * MAXNORMLEN, which should be plenty in real-world cases.
However a malicious affix file could supply an affix long
enough to overrun that. Defend by just rejecting the match
if it would overrun the buffer. I also inserted a check of
the input word length against Affix->replen, just to be sure
we won't index off the buffer, though it would be caller error
for that not to be true.
Also make the actual copying steps a bit more readable, and remove
an unnecessary requirement for the whole input word to fit into the
output buffer (even though it always will with the current caller).
The lack of documentation in this code makes my head hurt, so
I also reverse-engineered a basic header comment for CheckAffix.
Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/641711.1776792744@sss.pgh.pa.us
Backpatch-through: 14
Michael Paquier [Wed, 22 Apr 2026 01:34:38 +0000 (10:34 +0900)]
Allow ALTER INDEX .. ATTACH PARTITION to validate a parent index
This commit tweaks ALTER INDEX .. ATTACH PARTITION to attempt a
validation of a parent index in the case where an index is already
attached but the parent is not yet valid. This occurs in cases where a
parent index was created invalid such as with CREATE INDEX ONLY, but was
left invalid after an invalid child index was attached (partitioned
indexes set indisvalid to false if at least one partition is
!indisvalid, indisvalid is true in a partitioned table iff all
partitions are indisvalid). This could leave a partition tree in a
situation where a user could not bring the parent index back to valid
after fixing the child index, as there is no built-in mechanism to do
so. This commit relies on the fact that repeated ATTACH PARTITION
commands on the same index silently succeed.
An invalid parent index is more than just a passive issue. It causes
for example ON CONFLICT on a partitioned table if the invalid parent
index is used to enforce a unique constraint.
Some test cases are added to track some of problematic patterns, using a
set of partition trees with combinations of invalid indexes and ATTACH
PARTITION.
Reported-by: Mohamed Ali <moali.pg@gmail.com>
Author: Sami Imseih <sanmimseih@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Haibo Yan <tristan.yim@gmail.com>
Discussion: http://postgr.es/m/CAGnOmWqi1D9ycBgUeOGf6mOCd2Dcf=6sKhbf4sHLs5xAcKVCMQ@mail.gmail.com
Backpatch-through: 14
Tom Lane [Tue, 21 Apr 2026 14:54:39 +0000 (10:54 -0400)]
Make plpgsql_trap test more robust and less resource-intensive.
We were using "select count(*) into x from generate_series(1,
1_000_000_000_000)" to waste one second waiting for a statement
timeout trap. Aside from consuming CPU to little purpose, this could
easily eat several hundred MB of temporary file space, which has been
observed to cause out-of-disk-space errors in the buildfarm.
Let's just use "pg_sleep(10)", which is far less resource-intensive.
Also update the "when others" exception handler so that if it does
ever again trap an error, it will tell us what error. The cause of
these intermittent buildfarm failures had been obscure for awhile.
Richard Guo [Tue, 21 Apr 2026 05:31:15 +0000 (14:31 +0900)]
Fix incorrect NEW references to generated columns in rule rewriting
When a rule action or rule qualification references NEW.col where col
is a generated column (stored or virtual), the rewriter produces
incorrect results.
rewriteTargetListIU removes generated columns from the query's target
list, since stored generated columns are recomputed by the executor
and virtual ones store nothing. However, ReplaceVarsFromTargetList
then cannot find these columns when resolving NEW references during
rule rewriting. For UPDATE, the REPLACEVARS_CHANGE_VARNO fallback
redirects NEW.col to the original target relation, making it read the
pre-update value (same as OLD.col). For INSERT,
REPLACEVARS_SUBSTITUTE_NULL replaces it with NULL. Both are wrong
when the generated column depends on columns being modified.
Fix by building target list entries for generated columns from their
generation expressions, pre-resolving the NEW.attribute references
within those expressions against the query's targetlist, and passing
them together with the query's targetlist to ReplaceVarsFromTargetList.
Back-patch to all supported branches. Virtual generated columns were
added in v18, so the back-patches in pre-v18 branches only handle
stored generated columns.
Reported-by: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>
Author: Richard Guo <guofenglinux@gmail.com>
Author: Dean Rasheed <dean.a.rasheed@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAHg+QDexGTmCZzx=73gXkY2ZADS6LRhpnU+-8Y_QmrdTS6yUhA@mail.gmail.com
Backpatch-through: 14
Michael Paquier [Tue, 21 Apr 2026 00:40:07 +0000 (09:40 +0900)]
Fix orphaned processes when startup process fails during PM_STARTUP
When the startup process exists with a FATAL error during PM_STARTUP,
the postmaster called ExitPostmaster() directly, assuming that no other
processes are running at this stage. Since 7ff23c6d277d, this
assumption is not true, as the checkpointer, the background writer, the
IO workers and bgworkers kicking in early would be around.
This commit removes the startup-specific shortcut happening in
process_pm_child_exit() for a failing startup process during PM_STARTUP,
falling down to the existing exit() flow to signal all the started
children with SIGQUIT, so as we have no risk of creating orphaned
processes.
This required an extra change in HandleFatalError() for v18 and newer
versions, as an assertion could be triggered for PM_STARTUP. It is now
incorrect. In v17 and older versions, HandleChildCrash() needs to be
changed to handle PM_STARTUP so as children can be waited on.
While on it, fix a comment at the top of postmaster.c. It was claiming
that the checkpointer and the background writer were started after
PM_RECOVERY. That is not the case.
doc: Correct context description for some JIT support GUCs
The documentation for jit_debugging_support and jit_profiling_support
previously stated that these parameters can only be set at server start.
However, both parameters use the PGC_SU_BACKEND context, meaning they
can be set at session start by superusers or users granted the appropriate
SET privilege, but cannot be changed within an active session.
This commit updates the documentation to reflect the actual behavior.
doc: Improve description of pg_ctl -l log file permissions
The documentation stated only that the log file created by pg_ctl -l is
inaccessible to other users by default. However, since commit c37b3d0,
the actual behavior is that only the cluster owner has access by default,
but users in the same group as the cluster owner may also read the file
if group access is enabled in the cluster.
This commit updates the documentation to describe this behavior
more clearly.
Backpatch to all supported versions.
Author: Hayato Kuroda <kuroda.hayato@fujitsu.com> Reviewed-by: Andreas Karlsson <andreas@proxel.se> Reviewed-by: Xiaopeng Wang <wxp_728@163.com> Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/OS9PR01MB1214959BE987B4839E3046050F54BA@OS9PR01MB12149.jpnprd01.prod.outlook.com
Backpatch-through: 14
Thomas Munro [Thu, 16 Apr 2026 06:17:05 +0000 (18:17 +1200)]
Fix comments for Korean encodings in encnames.c
* JOHAB: replace the incorrect "simplified Chinese" description with
a correct one that identifies it as the Korean combining (Johab)
encoding standardized in KS X 1001 annex 3.
* EUC_KR: drop a stray space before the comma in the existing
comment, and note that the encoding covers the KS X 1001
precomposed (Wansung) form.
* UHC: spell out "Unified Hangul Code", clarify that it is
Microsoft Windows CodePage 949, and describe its relationship to
EUC-KR (superset covering all 11,172 precomposed Hangul syllables).
Michael Paquier [Tue, 14 Apr 2026 20:09:13 +0000 (05:09 +0900)]
Add tests for low-level PGLZ [de]compression routines
The goal of this module is to provide an entry point for the coverage of
the low-level compression and decompression PGLZ routines. The new test
is moved to a new parallel group, with all the existing
compression-related tests added to it.
This includes tests for the cases detected by fuzzing that emulate
corrupted compressed data, as fixed by 2b5ba2a0a141:
- Set control bit with read of a match tag, where no data follows.
- Set control bit with read of a match tag, where 1 byte follows.
- Set control bit with match tag where length nibble is 3 bytes
(extended case).
While on it, some tests are added for compress/decompress roundtrips,
and for check_complete=false/true. Like 2b5ba2a0a141, backpatch to all
the stable branches.
Michael Paquier [Sat, 11 Apr 2026 08:03:10 +0000 (17:03 +0900)]
Honor passed-in database OIDs in pgstat_database.c
Three routines in pgstat_database.c incorrectly ignore the database OID
provided by their caller, using MyDatabaseId instead:
- pgstat_report_connect()
- pgstat_report_disconnect()
- pgstat_reset_database_timestamp()
The first two functions, for connection and disconnection, each have a
single caller that already passes MyDatabaseId. This was harmless,
still incorrect.
The timestamp reset function also has a single caller, but in this case
the issue has a real impact: it fails to reset the timestamp for the
shared-database entry (datid=0) when operating on shared objects. This
situation can occur, for example, when resetting counters for shared
relations via pg_stat_reset_single_table_counters().
There is currently one test in the tree that checks the reset of a
shared relation, for pg_shdescription, we rely on it to check what is
stored in pg_stat_database. As stats_reset may be NULL, two resets are
done to provide a baseline for comparison.
Author: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Dapeng Wang <wangdp20191008@gmail.com>
Discussion: https://postgr.es/m/ABBD5026-506F-4006-A569-28F72C188693@gmail.com
Backpatch-through: 15
Andrew Dunstan [Thu, 9 Apr 2026 15:48:55 +0000 (11:48 -0400)]
Fix heap-buffer-overflow in pglz_decompress() on corrupt input.
When decoding a match tag, pglz_decompress() reads 2 bytes (or 3
for extended-length matches) from the source buffer before checking
whether enough data remains. The existing bounds check (sp > srcend)
occurs after the reads, so truncated compressed data that ends
mid-tag causes a read past the allocated buffer.
Fix by validating that sufficient source bytes are available before
reading each part of the match tag. The post-read sp > srcend
check is no longer needed and is removed.
Found by fuzz testing with libFuzzer and AddressSanitizer.
pg_node_attr was mistakenly interpreted to be the name of the field.
To fix this, add -I option to ctags command if the command is
Exuberant ctags or Universal ctags (for plain old ctags, struct
members are not included in the tags file anyway).
Also add "-e" and "-n" options to make_ctags. The -e option invokes
ctags command with -e option, which produces TAGS file for emacs. This
allows to eliminate duplicate codes in make_etags so that make_etags
just exec make_ctags with -e option.
The -n option allows not to produce symbolic links in each
sub directory (the default is producing symbolic links).
This includes the follow-up fixes: 87f21d2c6890 and ae66716bf3ef. This
change is applied to v15 and v14, v16 and nwer versions already
including these improvements. One reason why I am doing this backpatch
is that this can be really useful for backpatching purposes, especially
the -n option that limits the number of TAGS/tags files created in the
tree.
Richard Guo [Thu, 9 Apr 2026 10:28:33 +0000 (19:28 +0900)]
Fix integer overflow in nodeWindowAgg.c
In nodeWindowAgg.c, the calculations for frame start and end positions
in ROWS and GROUPS modes were performed using simple integer addition.
If a user-supplied offset was sufficiently large (close to INT64_MAX),
adding it to the current row or group index could cause a signed
integer overflow, wrapping the result to a negative number.
This led to incorrect behavior where frame boundaries that should have
extended indefinitely (or beyond the partition end) were treated as
falling at the first row, or where valid rows were incorrectly marked
as out-of-frame. Depending on the specific query and data, these
overflows can result in incorrect query results, execution errors, or
assertion failures.
To fix, use overflow-aware integer addition (ie, pg_add_s64_overflow)
to check for overflows during these additions. If an overflow is
detected, the boundary is now clamped to INT64_MAX. This ensures the
logic correctly treats the boundary as extending to the end of the
partition.
Bug: #19405 Reported-by: Alexander Lakhin <exclusion@gmail.com>
Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tender Wang <tndrwang@gmail.com>
Discussion: https://postgr.es/m/19405-1ecf025dda171555@postgresql.org
Backpatch-through: 14
Tom Lane [Mon, 6 Apr 2026 18:22:17 +0000 (14:22 -0400)]
Avoid unsafe access to negative index in a TupleDesc.
Commit aa606b931 installed a test that would reference a nonexistent
TupleDesc array entry if a system column is used in COPY FROM WHERE.
Typically this would be harmless, but with bad luck it could result
in a phony "generated columns are not supported in COPY FROM WHERE
conditions" error, and at least in principle it could cause SIGSEGV.
(Compare 570e2fcc0 which fixed the identical problem in another
place.) Also, since c98ad086a it throws an Assert instead.
In the back branches, just guard the test to make it a safe no-op for
system columns. Commit 21c69dc73 installed a more aggressive answer
in master.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/6f435023-8ab6-47c2-ba07-035d0c4212f9@gmail.com
Backpatch-through: 14-18
Thomas Munro [Fri, 3 Apr 2026 01:48:54 +0000 (14:48 +1300)]
jit: No backport::SectionMemoryManager for LLVM 22.
LLVM 22 has the fix that we copied into our tree in commit 9044fc1d and
a new function to reach it[1][2], so we only need to use our copy for
Aarch64 + LLVM < 22. The only change to the final version that our copy
didn't get is a new LLVM_ABI macro, but that isn't appropriate for us.
Our copy is hopefully now frozen and would only need maintenance if bugs
are found in the upstream code.
Non-Aarch64 systems now also use the new API with LLVM 22. It allocates
all sections with one contiguous mmap() instead of one per
section. We could have done that earlier, but commit 9044fc1d wanted to
limit the blast radius to the affected systems. We might as well
benefit from that small improvement everywhere now that it is available
out of the box.
We can't delete our copy until LLVM 22 is our minimum supported version,
or we switch to the newer JITLink API for at least Aarch64.
Thomas Munro [Thu, 2 Apr 2026 02:24:44 +0000 (15:24 +1300)]
jit: Stop emitting lifetime.end for LLVM 22.
The lifetime.end intrinsic can now only be used for stack memory
allocated with alloca[1][2][3]. We use it to tell LLVM about the
lifetime of function arguments/isnull values that we keep in palloc'd
memory, so that it can avoid spilling registers to memory.
We might need to rearrange things and put them on the stack, but that'll
take some research. In the meantime, unbreak the build on LLVM 22.
Author: Peter Smith <smithpb2250@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAHut%2BPv72haFerrCdYdmF6hu6o2jKcGzkXehom%2BsP-JBBmOVDg%40mail.gmail.com
Backpatch-through: 14
Tom Lane [Mon, 30 Mar 2026 17:59:54 +0000 (13:59 -0400)]
Be more careful to preserve consistency of a tuplestore.
Several places in tuplestore.c would leave the tuplestore data
structure effectively corrupt if some subroutine were to throw
an error. Notably, if WRITETUP() failed after some number of
successful calls within dumptuples(), the tuplestore would
contain some memtuples pointers that were apparently live
entries but in fact pointed to pfree'd chunks.
In most cases this sort of thing is fine because transaction
abort cleanup is not too picky about the contents of memory that
it's going to throw away anyway. There's at least one exception
though: if a Portal has a holdStore, we're going to call
tuplestore_end() on that, even during transaction abort.
So it's not cool if that tuplestore is corrupt, and that means
tuplestore.c has to be more careful.
This oversight demonstrably leads to crashes in v15 and before,
if a holdable cursor fails to persist its data due to an undersized
temp_file_limit setting. Very possibly the same thing can happen in
v16 and v17 as well, though the specific test case submitted failed
to fail there (cf. 095555daf). The failure is accidentally dodged
as of v18 because 590b045c3 got rid of tuplestore_end's retail tuple
deletion loop. Still, it seems unwise to permit tuplestores to become
internally inconsistent in any branch, so I've applied the same fix
across the board.
Since the known test case for this is rather expensive and doesn't
fail in recent branches, I've omitted it.
Bug: #19438 Reported-by: Dmitriy Kuzmin <kuzmin.db4@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/19438-9d37b179c56d43aa@postgresql.org
Backpatch-through: 14
David Rowley [Mon, 30 Mar 2026 03:17:39 +0000 (16:17 +1300)]
Fix datum_image_*()'s inability to detect sign-extension variations
Functions such as hash_numeric() are not careful to use the correct
PG_RETURN_*() macro according to the return type of that function as
defined in pg_proc. Because that function is meant to return int32,
when the hashed value exceeds 2^31, the 64-bit Datum value won't wrap to
a negative number, which means the Datum won't have the same value as it
would have had it been cast to int32 on a two's complement machine. This
isn't harmless as both datum_image_eq() and datum_image_hash() may receive
a Datum that's been formed and deformed from a tuple in some cases, and
not in other cases. When formed into a tuple, the Datum value will be
coerced into an integer according to the attlen as specified by the
TupleDesc. This can result in two Datums that should be equal being
classed as not equal, which could result in (but not limited to) an error
such as:
ERROR: could not find memoization table entry
Here we fix this by ensuring we cast the Datum value to a signed integer
according to the typLen specified in the datum_image_eq/datum_image_hash
function call before comparing or hashing.
Author: David Rowley <dgrowleyml@gmail.com> Reported-by: Tender Wang <tndrwang@gmail.com>
Backpatch-through: 14
Discussion: https://postgr.es/m/CAHewXNmcXVFdB9_WwA8Ez0P+m_TQy_KzYk5Ri5dvg+fuwjD_yw@mail.gmail.com
Andrew Dunstan [Sun, 29 Mar 2026 13:12:40 +0000 (09:12 -0400)]
Fix multiple bugs in astreamer pipeline code.
astreamer_tar_parser_content() sent the wrong data pointer when
forwarding MEMBER_TRAILER padding to the next streamer. After
astreamer_buffer_until() buffers the padding bytes, the 'data'
pointer has been advanced past them, but the code passed 'data'
instead of bbs_buffer.data. This caused the downstream consumer
to receive bytes from after the padding rather than the padding
itself, and could read past the end of the input buffer.
astreamer_gzip_decompressor_content() only checked for
Z_STREAM_ERROR from inflate(), silently ignoring Z_DATA_ERROR
(corrupted data) and Z_MEM_ERROR (out of memory). Fix by
treating any return other than Z_OK, Z_STREAM_END, and
Z_BUF_ERROR as fatal.
astreamer_gzip_decompressor_free() missed calling inflateEnd() to
release zlib's internal decompression state.
astreamer_tar_parser_free() neglected to pfree() the streamer
struct itself, leaking it.
astreamer_extractor_content() did not check the return value of
fclose() when closing an extracted file. A deferred write error
(e.g., disk full on buffered I/O) would be silently lost.
Fujii Masao [Thu, 26 Mar 2026 11:49:31 +0000 (20:49 +0900)]
Fix premature NULL lag reporting in pg_stat_replication
pg_stat_replication is documented to keep the last measured lag values for
a short time after the standby catches up, and then set them to NULL when
there is no WAL activity. However, previously lag values could become NULL
prematurely even while WAL activity was ongoing, especially in logical
replication.
This happened because the code cleared lag when two consecutive reply messages
indicated that the apply location had caught up with the send location.
It did not verify that the reported positions were unchanged, so lag could be
cleared even when positions had advanced between messages. In logical
replication, where the apply location often quickly catches up, this issue was
more likely to occur.
This commit fixes the issue by clearing lag only when the standby reports that
it has fully replayed WAL (i.e., both flush and apply locations have caught up
with the send location) and the write/flush/apply positions remain unchanged
across two consecutive reply messages.
The second message with unchanged positions typically results from
wal_receiver_status_interval, so lag values are cleared after that interval
when there is no activity. This avoids showing stale lag data while preventing
premature NULL values.
Even with this fix, lag may rarely become NULL during activity if identical
position reports are sent repeatedly. Eliminating such duplicate messages
would address this fully, but that change is considered too invasive for stable
branches and will be handled in master only later.
John Naylor [Tue, 24 Mar 2026 09:40:33 +0000 (16:40 +0700)]
Fix copy-paste error in test_ginpostinglist
The check for a mismatch on the second decoded item pointer
was an exact copy of the first item pointer check, comparing
orig_itemptrs[0] with decoded_itemptrs[0] instead of orig_itemptrs[1]
with decoded_itemptrs[1]. The error message also reported (0, 1) as
the expected value instead of (blk, off). As a result, any decoding
error in the second item pointer (where the varbyte delta encoding
is exercised) would go undetected.
This has been wrong since commit bde7493d1, so backpatch to all
supported versions.
Author: Jianghua Yang <yjhjstz@gmail.com>
Discussion: https://postgr.es/m/CAAZLFmSOD8R7tZjRLZsmpKtJLoqjgawAaM-Pne1j8B_Q2aQK8w@mail.gmail.com
Backpatch-through: 14
Fix multixact backwards-compatibility with CHECKPOINT race condition
If a CHECKPOINT record with nextMulti N is written to the WAL before
the CREATE_ID record for N, and N happens to be the first multixid on
an offset page, the backwards compatibility logic to tolerate WAL
generated by older minor versions (before commit 789d65364c) failed to
compensate for the missing XLOG_MULTIXACT_ZERO_OFF_PAGE record. In
that case, the latest_page_number was initialized at the start of WAL
replay to the page for nextMulti from the CHECKPOINT record, even if
we had not seen the CREATE_ID record for that multixid yet, which
fooled the backwards compatibility logic to think that the page was
already initialized.
To fix, track the last XLOG_MULTIXACT_ZERO_OFF_PAGE that we've seen
separately from latest_page_number. If we haven't seen any
XLOG_MULTIXACT_ZERO_OFF_PAGE records yet, use
SimpleLruDoesPhysicalPageExist() to check if the page needs to be
initialized.
Tom Lane [Sun, 22 Mar 2026 22:06:48 +0000 (18:06 -0400)]
Fix finalization of decompressor astreamers.
Send the correct amount of data to the next astreamer, not the
whole allocated buffer size. This bug escaped detection because
in present uses the next astreamer is always a tar-file parser
which is insensitive to trailing garbage. But that may not
be true in future uses.
Author: Andrew Dunstan <andrew@dunslane.net> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/2178517.1774064942@sss.pgh.pa.us
Backpatch-through: 15
Fujii Masao [Mon, 16 Mar 2026 23:10:20 +0000 (08:10 +0900)]
Fix WAL flush LSN used by logical walsender during shutdown
Commit 6eedb2a5fd8 made the logical walsender call
XLogFlush(GetXLogInsertRecPtr()) to ensure that all pending WAL is flushed,
fixing a publisher shutdown hang. However, if the last WAL record ends at
a page boundary, GetXLogInsertRecPtr() can return an LSN pointing past
the page header, which can cause XLogFlush() to report an error.
A similar issue previously existed in the GiST code. Commit b1f14c96720
introduced GetXLogInsertEndRecPtr(), which returns a safe WAL insertion end
location (returning the start of the page when the last record ends at a page
boundary), and updated the GiST code to use it with XLogFlush().
This commit fixes the issue by making the logical walsender use
XLogFlush(GetXLogInsertEndRecPtr()) when flushing pending WAL during shutdown.
Tomas Vondra [Sat, 14 Mar 2026 14:24:37 +0000 (15:24 +0100)]
Tighten asserts on ParallelWorkerNumber
The comment about ParallelWorkerNumbr in parallel.c says:
In parallel workers, it will be set to a value >= 0 and < the number
of workers before any user code is invoked; each parallel worker will
get a different parallel worker number.
However asserts in various places collecting instrumentation allowed
(ParallelWorkerNumber == num_workers). That would be a bug, as the value
is used as index into an array with num_workers entries.
Fixed by adjusting the asserts accordingly. Backpatch to all supported
versions.
Tomas Vondra [Fri, 13 Mar 2026 21:42:29 +0000 (22:42 +0100)]
Use GetXLogInsertEndRecPtr in gistGetFakeLSN
The function used GetXLogInsertRecPtr() to generate the fake LSN. Most
of the time this is the same as what XLogInsert() would return, and so
it works fine with the XLogFlush() call. But if the last record ends at
a page boundary, GetXLogInsertRecPtr() returns LSN pointing after the
page header. In such case XLogFlush() fails with errors like this:
ERROR: xlog flush request 0/01BD2018 is not satisfied --- flushed only to 0/01BD2000
Such failures are very hard to trigger, particularly outside aggressive
test scenarios.
Fixed by introducing GetXLogInsertEndRecPtr(), returning the correct LSN
without skipping the header. This is the same as GetXLogInsertRecPtr(),
except that it calls XLogBytePosToEndRecPtr().
Initial investigation by me, root cause identified by Andres Freund.
This is a long-standing bug in gistGetFakeLSN(), probably introduced by c6b92041d38 in PG13. Backpatch to all supported versions.
Reported-by: Peter Geoghegan <pg@bowt.ie> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/vf4hbwrotvhbgcnknrqmfbqlu75oyjkmausvy66ic7x7vuhafx@e4rvwavtjswo
Backpatch-through: 14
Michael Paquier [Fri, 13 Mar 2026 07:06:50 +0000 (16:06 +0900)]
xml2: Fix failure with xslt_process() under -fsanitize=undefined
The logic of xslt_process() has never considered the fact that
xsltSaveResultToString() would return NULL for an empty string (the
upstream code has always done so, with a string length of 0). This
would cause memcpy() to be called with a NULL pointer, something
forbidden by POSIX.
Like 46ab07ffda9d and similar fixes, this is backpatched down to all the
supported branches, with a test case to cover this scenario. An empty
string has been always returned in xml2 in this case, based on the
history of the module, so this is an old issue.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/c516a0d9-4406-47e3-9087-5ca5176ebcf9@gmail.com
Backpatch-through: 14
Fujii Masao [Mon, 9 Mar 2026 09:24:41 +0000 (18:24 +0900)]
doc: Document IF NOT EXISTS option for ALTER FOREIGN TABLE ADD COLUMN.
Commit 2cd40adb85d added the IF NOT EXISTS option to ALTER TABLE ADD COLUMN.
This also enabled IF NOT EXISTS for ALTER FOREIGN TABLE ADD COLUMN,
but the ALTER FOREIGN TABLE documentation was not updated to mention it.
This commit updates the documentation to describe the IF NOT EXISTS option for
ALTER FOREIGN TABLE ADD COLUMN.
While updating that section, also this commit clarifies that the COLUMN keyword
is optional in ALTER FOREIGN TABLE ADD/DROP COLUMN. Previously, part of
the documentation could be read as if COLUMN were required.
This commit adds regression tests covering these ALTER FOREIGN TABLE syntaxes.
Backpatch to all supported versions.
Suggested-by: Fujii Masao <masao.fujii@gmail.com>
Author: Chao Li <lic@highgo.com> Reviewed-by: Robert Treat <rob@xzilla.net> Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/CAHGQGwFk=rrhrwGwPtQxBesbT4DzSZ86Q3ftcwCu3AR5bOiXLw@mail.gmail.com
Backpatch-through: 14
Michael Paquier [Mon, 9 Mar 2026 04:46:37 +0000 (13:46 +0900)]
Fix size underestimation of DSA pagemap for odd-sized segments
When make_new_segment() creates an odd-sized segment, the pagemap was
only sized based on a number of usable_pages entries, forgetting that a
segment also contains metadata pages, and that the FreePageManager uses
absolute page indices that cover the entire segment. This
miscalculation could cause accesses to pagemap entries to be out of
bounds. During subsequent reuse of the allocated segment, allocations
landing on pages with indices higher than usable_pages could cause
out-of-bounds pagemap reads and/or writes. On write, 'span' pointers
are stored into the data area, corrupting the allocated objects. On
read (aka during a dsa_free), garbage is interpreted as a span pointer,
typically crashing the server in dsa_get_address().
The normal geometric path correctly sizes the pagemap for all pages in
the segment. The odd-sized path needs to do the same, but it works
forward from usable_pages rather than backward from total_size.
This commit fixes the sizing of the odd-sized case by adding pagemap
entries for the metadata pages after the initial metadata_bytes
calculation, using an integer ceiling division to compute the exact
number of additional entries needed in one go, avoiding any iteration in
the calculation.
An assertion is added in the code path for odd-sized segments, ensuring
that the pagemap includes the metadata area, and that the result is
appropriately sized.
This problem would show up depending on the size requested for the
allocation of a DSA segment. The reporter has noticed this issue when a
parallel hash join makes a DSA allocation large enough to trigger the
odd-sized segment path, but it could happen for anything that does a DSA
allocation.
A regression test is added to test_dsa, down to v17 where the test
module has been introduced. This adds a set of cheap tests to check the
problem, the new assertion being useful for this purpose. Sami has
proposed a test that took a longer time than what I have done here; the
test committed is faster and good enough to check the odd-sized
allocation path.
Author: Paul Bunn <paul.bunn@icloud.com> Reviewed-by: Sami Imseih <samimseih@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/044401dcabac$fe432490$fac96db0$@icloud.com
Backpatch-through: 14
Fujii Masao [Fri, 6 Mar 2026 07:43:40 +0000 (16:43 +0900)]
Fix publisher shutdown hang caused by logical walsender busy loop.
Previously, when logical replication was running, shutting down
the publisher could cause the logical walsender to enter a busy loop
and prevent the publisher from completing shutdown.
During shutdown, the logical walsender waits for all pending WAL
to be written out. However, some WAL records could remain unflushed,
causing the walsender to wait indefinitely.
The issue occurred because the walsender used XLogBackgroundFlush() to
flush pending WAL. This function does not guarantee that all WAL is written.
For example, WAL generated by a transaction without an assigned
transaction ID that aborts might not be flushed.
This commit fixes the bug by making the logical walsender call XLogFlush()
instead, ensuring that all pending WAL is written and preventing
the busy loop during shutdown.
Tom Lane [Thu, 5 Mar 2026 19:43:21 +0000 (14:43 -0500)]
Exit after fatal errors in client-side compression code.
It looks like whoever wrote the astreamer (nee bbstreamer) code
thought that pg_log_error() is equivalent to elog(ERROR), but
it's not; it just prints a message. So all these places tried to
continue on after a compression or decompression error return,
with the inevitable result being garbage output and possibly
cascading error messages. We should use pg_fatal() instead.
These error conditions are probably pretty unlikely in practice,
which no doubt accounts for the lack of field complaints.
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/1531718.1772644615@sss.pgh.pa.us
Backpatch-through: 15
Fix handling of updated tuples in the MERGE statement
This branch missed the IsolationUsesXactSnapshot() check. That led to EPQ on
repeatable read and serializable isolation levels. This commit fixes the
issue and provides a simple isolation check for that. Backpatch through v15
where MERGE statement was introduced.
Reported-by: Tender Wang <tndrwang@gmail.com>
Discussion: https://postgr.es/m/CAPpHfdvzZSaNYdj5ac-tYRi6MuuZnYHiUkZ3D-AoY-ny8v%2BS%2Bw%40mail.gmail.com
Author: Tender Wang <tndrwang@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Backpatch-through: 15
Fujii Masao [Thu, 5 Mar 2026 03:57:52 +0000 (12:57 +0900)]
doc: Clarify that COLUMN is optional in ALTER TABLE ... ADD/DROP COLUMN.
In ALTER TABLE ... ADD/DROP COLUMN, the COLUMN keyword is optional. However,
part of the documentation could be read as if COLUMN were required, which may
mislead users about the command syntax.
This commit updates the ALTER TABLE documentation to clearly state that
COLUMN is optional for ADD and DROP.
Also this commit adds regression tests covering ALTER TABLE ... ADD/DROP
without the COLUMN keyword.
Backpatch to all supported versions.
Author: Chao Li <lic@highgo.com> Reviewed-by: Robert Treat <rob@xzilla.net> Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/CAEoWx2n6ShLMOnjOtf63TjjgGbgiTVT5OMsSOFmbjGb6Xue1Bw@mail.gmail.com
Backpatch-through: 14
Michael Paquier [Thu, 5 Mar 2026 01:06:06 +0000 (10:06 +0900)]
Fix rare instability in recovery TAP test 004_timeline_switch
This fixes a problem similar to ad8c86d22cbd. In this case, the test
could fail under the following circumstances:
- The primary is stopped with teardown_node(), meaning that it may not
be able to send all its WAL records to standby_1 and standby_2.
- If standby_2 receives more records than standby_1, attempting to
reconnect standby_2 to the promoted standby_1 would fail because of a
timeline fork.
This race condition is fixed with a simple trick: instead of tearing
down the primary, it is stopped cleanly so as all the WAL records of the
primary are received and flushed by both standby_1 and standby_2. Once
we do that, there is no need for a wait_for_catchup() before stopping
the node. The test wants to check that a timeline jump can be achieved
when reconnecting a standby to a promoted standby in the same cluster,
hence an immediate stop of the primary is not required.
This failure is harder to reach than the previous instability of
009_twophase, still the buildfarm has been able to detect this failure
at least once. I have tried Alexander Lakhin's test trick with the
bgwriter and very aggressive standby snapshots, but I could not
reproduce it directly. It is reachable, as the buildfarm has proved.
Backpatch down to all supported branches, and this problem can lead to
spurious failures in the buildfarm.
Tom Lane [Wed, 4 Mar 2026 17:08:37 +0000 (12:08 -0500)]
Fix yet another bug in archive streamer with LZ4 decompression.
The code path in astreamer_lz4_decompressor_content() that updated
the output pointers when the output buffer isn't full was wrong.
It advanced next_out by bytes_written, which could include previous
decompression output not just that of the current cycle. The
correct amount to advance is out_size. While at it, make the
output pointer updates look more like the input pointer updates.
This bug is pretty hard to reach, as it requires consecutive
compression frames that are too small to fill the output buffer.
pg_dump could have produced such data before 66ec01dc4, but
I'm unsure whether any files we use astreamer with would be
likely to contain problematic data.
Author: Chao Li <lic@highgo.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/0594CC79-1544-45DD-8AA4-26270DE777A7@gmail.com
Backpatch-through: 15
Michael Paquier [Wed, 4 Mar 2026 07:31:03 +0000 (16:31 +0900)]
Fix rare instability in recovery TAP test 009_twophase
The phase of the test where we want to check that 2PC transactions
prepared on a primary can be committed on a promoted standby relied on
an immediate stop of the primary. This logic has a race condition: it
could be possible that some records (most likely standby snapshot
records) are generated on the primary before it finishes its shutdown,
without the promoted standby know about them. When the primary is
recycled as new standby, the test could fail because of a timeline fork
as an effect of these extra records.
This fix takes care of the instability by doing a clean stop of the
primary instead of a teardown (aka immediate stop), so as all records
generated on the primary are sent to the promoted standby and flushed
there. There is no need for a teardown of the primary in this test
scenario: the commit of 2PC transactions on a promoted standby do not
care about the state of the primary, only of the standby.
This race is very hard to hit in practice, even slow buildfarm members
like skink have a very low rate of reproduction. Alexander Lakhin has
come up with a recipe to improve the reproduction rate a lot:
- Enable -DWAL_DEBUG.
- Patch the bgwriter so as standby snapshots are generated every
milliseconds.
- Run 009_twophase tests under heavy parallelism.
With this method, the failure appears after a couple of iterations.
With the fix in place, I have been able to run more than 50 iterations
of the parallel test sequence, without seeing a failure.
Issue introduced in 30820982b295, due to a copy-pasto coming from the
surrounding tests. Thanks also to Hayato Kuroda for digging into the
details of the failure. He has proposed a fix different than the one of
this commit. Unfortunately, it relied on injection points, feature only
available in v17. The solution of this commit is simpler, and can be
applied to v14~v16.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/b0102688-6d6c-c86a-db79-e0e91d245b1a@gmail.com
Backpatch-through: 14
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
Michael Paquier [Mon, 2 Mar 2026 02:10:39 +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
Michael Paquier [Mon, 2 Mar 2026 00:38:46 +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
Jeff Davis [Thu, 26 Feb 2026 20:26:13 +0000 (12:26 -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().
Tom Lane [Thu, 26 Feb 2026 17:26:52 +0000 (12:26 -0500)]
Fix Solution.pm for change in pg_config.h contents.
In commits 1d97e4788 et al, I forgot that pre-v17 branches
require updating Solution.pm when changing the set of
symbols generated in pg_config.h. Per buildfarm.
Tom Lane [Thu, 26 Feb 2026 17:06:58 +0000 (12:06 -0500)]
Use CXXFLAGS instead of CFLAGS for linking C++ code
Otherwise, this would break if using C and C++ compilers from
different families and they understand different options. It already
used the right flags for compiling, this is only for linking. Also,
the meson setup already did this correctly.
Back-patch of v18 commit 365b5a345 into older supported branches.
At the time we were only aware of trouble in v18, but as shown
by buildfarm member siren, older branches can hit the problem too.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Author: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://www.postgresql.org/message-id/228700.1722717983@sss.pgh.pa.us
Discussion: https://postgr.es/m/3109540.1771698685@sss.pgh.pa.us
Backpatch-through: 14-17
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 00:02:53 +0000 (09:02 +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 16:57:26 +0000 (11:57 -0500)]
Allow PG_PRINTF_ATTRIBUTE to be different in C and C++ code.
Although clang claims to be compatible with gcc's printf format
archetypes, this appears to be a falsehood: it likes __syslog__
(which gcc does not, on most platforms) and doesn't accept
gnu_printf. This means that if you try to use gcc with clang++
or clang with g++, you get compiler warnings when compiling
printf-like calls in our C++ code. This has been true for quite
awhile, but it's gotten more annoying with the recent appearance
of several buildfarm members that are configured like this.
To fix, run separate probes for the format archetype to use with the
C and C++ compilers, and conditionally define PG_PRINTF_ATTRIBUTE
depending on __cplusplus.
(We could alternatively insist that you not mix-and-match C and
C++ compilers; but if the case works otherwise, this is a poor
reason to insist on that.)
This commit back-patches 0909380e4 into supported branches.
Tom Lane [Wed, 25 Feb 2026 16:19:50 +0000 (11:19 -0500)]
Fix some cases of indirectly casting away const.
Newest versions of gcc+glibc are able to detect cases where code
implicitly casts away const by assigning the result of strchr() or
a similar function applied to a "const char *" value to a target
variable that's just "char *". This of course creates a hazard of
not getting a compiler warning about scribbling on a string one was
not supposed to, so fixing up such cases is good.
This patch fixes a dozen or so places where we were doing that.
Most are trivial additions of "const" to the target variable,
since no actually-hazardous change was occurring.
Thanks to Bertrand Drouvot for finding a couple more spots than
I had.
This commit back-patches relevant portions of 8f1791c61 and 9f7565c6c into supported branches. However, there are two
places in ecpg (in v18 only) where a proper fix is more
complicated than seems appropriate for a back-patch. I opted
to silence those two warnings by adding casts.
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/1324889.1764886170@sss.pgh.pa.us
Discussion: https://postgr.es/m/3988414.1771950285@sss.pgh.pa.us
Backpatch-through: 14-18
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
Jacob Champion [Tue, 24 Feb 2026 22:01:54 +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
Thomas Munro [Tue, 17 Feb 2026 00:53:32 +0000 (13:53 +1300)]
Fix test_valid_server_encoding helper function.
Commit c67bef3f325 introduced this test helper function for use by
src/test/regress/sql/encoding.sql, but its logic was incorrect. It
confused an encoding ID for a boolean so it gave the wrong results for
some inputs, and also forgot the usual return macro. The mistake didn't
affect values actually used in the test, so there is no change in
behavior.
Also drop it and another missed function at the end of the test, for
consistency.
Noah Misch [Tue, 17 Feb 2026 02:04:58 +0000 (18:04 -0800)]
Suppress new "may be used uninitialized" warning.
Various buildfarm members, having compilers like gcc 8.5 and 6.3, fail
to deduce that text_substring() variable "E" is initialized if
slice_size!=-1. This suppression approach quiets gcc 8.5; I did not
reproduce the warning elsewhere. Back-patch to v14, like commit 9f4fd119b2cbb9a41ec0c19a8d6ec9b59b92c125.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1157953.1771266105@sss.pgh.pa.us
Backpatch-through: 14
Michael Paquier [Mon, 16 Feb 2026 23:41:35 +0000 (08:41 +0900)]
hstore: Fix NULL pointer dereference with receive function
The receive function of hstore was not able to handle correctly
duplicate key values when a new duplicate links to a NULL value, where a
pfree() could be attempted on a NULL pointer, crashing due to a pointer
dereference.
This problem would happen for a COPY BINARY, when stacking values like
that:
aa => 5
aa => null
The second key/value pair is discarded and pfree() calls are attempted
on its key and its value, leading to a pointer dereference for the value
part as the value is NULL. The first key/value pair takes priority when
a duplicate is found.
Don't reset 'latest_page_number' when replaying multixid truncation
'latest_page_number' is set to the correct value, according to
nextOffset, early at system startup. Contrary to the comment, it hence
should be set up correctly by the time we get to WAL replay.
This fixes a failure to replay WAL generated on older minor versions,
before commit 789d65364c (18.2, 17.8, 16.12, 15.16, 14.21). The
failure occurs after a truncation record has been replayed and looks
like this:
FATAL: could not access status of transaction 858112
DETAIL: Could not read from file "pg_multixact/offsets/000D" at offset 24576: read too few bytes.
CONTEXT: WAL redo at 3/2A3AB408 for MultiXact/CREATE_ID: 858111 offset 6695072 nmembers 5: 1048228 (sh) 1048271 (keysh) 1048316 (sh) 1048344 (keysh) 1048370 (sh)
Michael Paquier [Mon, 16 Feb 2026 03:18:33 +0000 (12:18 +0900)]
pgcrypto: Tweak error message for incorrect session key length
The error message added in 379695d3cc70 referred to the public key being
too long. This is confusing as it is in fact the session key included
in a PGP message which is too long. This is harmless, but let's be
precise about what is wrong.
Noah Misch [Sat, 14 Feb 2026 20:16:16 +0000 (12:16 -0800)]
Fix SUBSTRING() for toasted multibyte characters.
Commit 1e7fe06c10c0a8da9dd6261a6be8d405dc17c728 changed
pg_mbstrlen_with_len() to ereport(ERROR) if the input ends in an
incomplete character. Most callers want that. text_substring() does
not. It detoasts the most bytes it could possibly need to get the
requested number of characters. For example, to extract up to 2 chars
from UTF8, it needs to detoast 8 bytes. In a string of 3-byte UTF8
chars, 8 bytes spans 2 complete chars and 1 partial char.
Fix this by replacing this pg_mbstrlen_with_len() call with a string
traversal that differs by stopping upon finding as many chars as the
substring could need. This also makes SUBSTRING() stop raising an
encoding error if the incomplete char is past the end of the substring.
This is consistent with the general philosophy of the above commit,
which was to raise errors on a just-in-time basis. Before the above
commit, SUBSTRING() never raised an encoding error.
SUBSTRING() has long been detoasting enough for one more char than
needed, because it did not distinguish exclusive and inclusive end
position. For avoidance of doubt, stop detoasting extra.
Back-patch to v14, like the above commit. For applications using
SUBSTRING() on non-ASCII column values, consider applying this to your
copy of any of the February 12, 2026 releases.
Noah Misch [Sat, 14 Feb 2026 20:16:16 +0000 (12:16 -0800)]
pg_mblen_range, pg_mblen_with_len: Valgrind after encoding ereport.
The prior order caused spurious Valgrind errors. They're spurious
because the ereport(ERROR) non-local exit discards the pointer in
question. pg_mblen_cstr() ordered the checks correctly, but these other
two did not. Back-patch to v14, like commit 1e7fe06c10c0a8da9dd6261a6be8d405dc17c728.
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/20260214053821.fa.noahmisch@microsoft.com
Backpatch-through: 14
Tom Lane [Wed, 11 Feb 2026 21:53:14 +0000 (16:53 -0500)]
Fix plpgsql's handling of "return simple_record_variable".
If the variable's value is null, exec_stmt_return() missed filling
in estate->rettype. This is a pretty old bug, but we'd managed not
to notice because that value isn't consulted for a null result ...
unless we have to cast it to a domain. That case led to a failure
with "cache lookup failed for type 0".
The correct way to assign the data type is known by exec_eval_datum.
While we could copy-and-paste that logic, it seems like a better
idea to just invoke exec_eval_datum, as the ROW case already does.
Reported-by: Pavel Stehule <pavel.stehule@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAFj8pRBT_ahexDf-zT-cyH8bMR_qcySKM8D5nv5MvTWPiatYGA@mail.gmail.com
Backpatch-through: 14
Fix pg_stat_get_backend_wait_event() for aux processes
The pg_stat_activity view shows information for aux processes, but the
pg_stat_get_backend_wait_event() and
pg_stat_get_backend_wait_event_type() functions did not. To fix, call
AuxiliaryPidGetProc(pid) if BackendPidGetProc(pid) returns NULL, like
we do in pg_stat_get_activity().
In version 17 and above, it's a little silly to use those functions
when we already have the ProcNumber at hand, but it was necessary
before v17 because the backend ID was different from ProcNumber. I
have other plans for wait_event_info on master, so it doesn't seem
worth applying a different fix on different versions now.
Reviewed-by: Sami Imseih <samimseih@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://www.postgresql.org/message-id/c0320e04-6e85-4c49-80c5-27cfb3a58108@iki.fi
Backpatch-through: 14
Tom Lane [Wed, 11 Feb 2026 16:03:01 +0000 (11:03 -0500)]
Further stabilize a postgres_fdw test case.
The buildfarm occasionally shows a variant row order in the output
of this UPDATE ... RETURNING, implying that the preceding INSERT
dropped one of the rows into some free space within the table rather
than appending them all at the end. It's not entirely clear why that
happens some times and not other times, but we have established that
it's affected by concurrent activity in other databases of the
cluster. In any case, the behavior is not wrong; the test is at fault
for presuming that a seqscan will give deterministic row ordering.
Add an ORDER BY atop the update to stop the buildfarm noise.
The buildfarm seems to have shown this only in v18 and master
branches, but just in case the cause is older, back-patch to
all supported branches.
Dean Rasheed [Wed, 11 Feb 2026 10:53:01 +0000 (10:53 +0000)]
doc: Mention all SELECT privileges required by INSERT ... ON CONFLICT.
On the INSERT page, mention that SELECT privileges are also required
for any columns mentioned in the arbiter clause, including those
referred to by the constraint, and clarify that this applies to all
forms of ON CONFLICT, not just ON CONFLICT DO UPDATE.
Author: Dean Rasheed <dean.a.rasheed@gmail.com> Reviewed-by: Viktor Holmberg <v@viktorh.net>
Discussion: https://postgr.es/m/CAEZATCXGwMQ+x00YY9XYG46T0kCajH=21QaYL9Xatz0dLKii+g@mail.gmail.com
Backpatch-through: 14
Dean Rasheed [Wed, 11 Feb 2026 10:25:08 +0000 (10:25 +0000)]
doc: Clarify RLS policies applied for ON CONFLICT DO NOTHING.
On the CREATE POLICY page, the description of per-command policies
stated that SELECT policies are applied when an INSERT has an ON
CONFLICT DO NOTHING clause. However, that is only the case if it
includes an arbiter clause, so clarify that.
While at it, also clarify the comment in the regression tests that
cover this.
Author: Dean Rasheed <dean.a.rasheed@gmail.com> Reviewed-by: Viktor Holmberg <v@viktorh.net>
Discussion: https://postgr.es/m/CAEZATCXGwMQ+x00YY9XYG46T0kCajH=21QaYL9Xatz0dLKii+g@mail.gmail.com
Backpatch-through: 14
Tom Lane [Mon, 9 Feb 2026 15:14:22 +0000 (10:14 -0500)]
Harden _int_matchsel() against being attached to the wrong operator.
While the preceding commit prevented such attachments from occurring
in future, this one aims to prevent further abuse of any already-
created operator that exposes _int_matchsel to the wrong data types.
(No other contrib module has a vulnerable selectivity estimator.)
We need only check that the Const we've found in the query is indeed
of the type we expect (query_int), but there's a difficulty: as an
extension type, query_int doesn't have a fixed OID that we could
hard-code into the estimator.
Therefore, the bulk of this patch consists of infrastructure to let
an extension function securely look up the OID of a datatype
belonging to the same extension. (Extension authors have requested
such functionality before, so we anticipate that this code will
have additional non-security uses, and may soon be extended to allow
looking up other kinds of SQL objects.)
This is done by first finding the extension that owns the calling
function (there can be only one), and then thumbing through the
objects owned by that extension to find a type that has the desired
name. This is relatively expensive, especially for large extensions,
so a simple cache is put in front of these lookups.
Reported-by: Daniel Firer as part of zeroday.cloud
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Noah Misch <noah@leadboat.com>
Security: CVE-2026-2004
Backpatch-through: 14
Tom Lane [Mon, 9 Feb 2026 15:07:31 +0000 (10:07 -0500)]
Require superuser to install a non-built-in selectivity estimator.
Selectivity estimators come in two flavors: those that make specific
assumptions about the data types they are working with, and those
that don't. Most of the built-in estimators are of the latter kind
and are meant to be safely attachable to any operator. If the
operator does not behave as the estimator expects, you might get a
poor estimate, but it won't crash.
However, estimators that do make datatype assumptions can malfunction
if they are attached to the wrong operator, since then the data they
get from pg_statistic may not be of the type they expect. This can
rise to the level of a security problem, even permitting arbitrary
code execution by a user who has the ability to create SQL objects.
To close this hole, establish a rule that built-in estimators are
required to protect themselves against being called on the wrong type
of data. It does not seem practical however to expect estimators in
extensions to reach a similar level of security, at least not in the
near term. Therefore, also establish a rule that superuser privilege
is required to attach a non-built-in estimator to an operator.
We expect that this restriction will have little negative impact on
extensions, since estimators generally have to be written in C and
thus superuser privilege is required to create them in the first
place.
This commit changes the privilege checks in CREATE/ALTER OPERATOR
to enforce the rule about superuser privilege, and fixes a couple
of built-in estimators that were making datatype assumptions without
sufficiently checking that they're valid.
Reported-by: Daniel Firer as part of zeroday.cloud
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Noah Misch <noah@leadboat.com>
Security: CVE-2026-2004
Backpatch-through: 14
Tom Lane [Mon, 9 Feb 2026 15:02:23 +0000 (10:02 -0500)]
Add a syscache on pg_extension.oid.
An upcoming patch requires this cache so that it can track updates
in the pg_extension catalog. So far though, the EXTENSIONOID cache
only exists in v18 and up (see 490f869d9). We can add it in older
branches without an ABI break, if we are careful not to disturb the
numbering of existing syscache IDs.
In v16 and before, that just requires adding the new ID at the end
of the hand-assigned enum list, ignoring our convention about
alphabetizing the IDs. But in v17, genbki.pl enforces alphabetical
order of the IDs listed in MAKE_SYSCACHE macros. We can fake it
out by calling the new cache ZEXTENSIONOID.
Note that adding a syscache does change the required contents of the
relcache init file (pg_internal.init). But that isn't problematic
since we blow those away at postmaster start for other reasons.
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Noah Misch <noah@leadboat.com>
Security: CVE-2026-2004
Backpatch-through: 14-17
Tom Lane [Mon, 9 Feb 2026 14:57:44 +0000 (09:57 -0500)]
Guard against unexpected dimensions of oidvector/int2vector.
These data types are represented like full-fledged arrays, but
functions that deal specifically with these types assume that the
array is 1-dimensional and contains no nulls. However, there are
cast pathways that allow general oid[] or int2[] arrays to be cast
to these types, allowing these expectations to be violated. This
can be exploited to cause server memory disclosure or SIGSEGV.
Fix by installing explicit checks in functions that accept these
types.
Reported-by: Altan Birler <altan.birler@tum.de>
Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Noah Misch <noah@leadboat.com>
Security: CVE-2026-2003
Backpatch-through: 14
projects / thirdparty / postgresql.git / log
