multirange_recv and BlockRefTableReaderNextRelation were incautious
about multiplying a possibly-large integer by a factor more than 1
and then using it as an allocation size. This is harmless on 64-bit
systems where we'd compute a size exceeding MaxAllocSize and then
fail, but on 32-bit systems we could overflow size_t leading to an
undersized allocation and buffer overrun.
Fix these places by using palloc_array() instead of a handwritten
multiplication. (In HEAD, some of them were fixed already, but
none of that work got back-patched at the time.)
In addition, BlockRefTableReaderNextRelation passes the same value
to BlockRefTableRead's "int length" parameter. If built for
64-bit frontend code, palloc_array() allows a larger array size
than it otherwise would, potentially allowing that parameter to
overflow. Add an explicit check to forestall that and keep the
behavior the same cross-platform.
Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us>
Backpatch-through: 14
Security: CVE-2026-6473
Some UTF8 characters decompose to more than a dozen codepoints.
It is possible for an input string that fits into well under
1GB to produce more than 4G decomposed codepoints, causing
unicode_normalize()'s decomp_size variable to wrap around to a
small positive value. This results in a small output buffer
allocation and subsequent buffer overrun.
To fix, test after each addition to see if we've overrun MaxAllocSize,
and break out of the loop early if so. In frontend code we want to
just return NULL for this failure (treating it like OOM). In the
backend, we can rely on the following palloc() call to throw error.
I also tightened things up in the calling functions in varlena.c,
using size_t rather than int and allocating the input workspace
with palloc_array(). These changes are probably unnecessary
given the knowledge that the original input and the normalized
output_chars array must fit into 1GB, but it's a lot easier to
believe the code is safe with these changes.
Reported-by: Xint Code
Reported-by: Bruce Dang <bruce@calif.io>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Co-authored-by: Heikki Linnakangas <hlinnaka@iki.fi>
Backpatch-through: 14
Security: CVE-2026-6473
The number of NFA states, number of NFA arcs, and number of colors
are all bounded to reasonably small values. However, there are
places where we try to allocate arrays sized by products of those
quantities, and those calculations could overflow, enabling
buffer-overrun attacks. In practice there's no problem on 64-bit
machines, but there are some live scenarios on 32-bit machines.
A related problem is that citerdissect() and creviterdissect()
allocate arrays based on the length of the input string, which
potentially could overflow.
To fix, invent MALLOC_ARRAY and REALLOC_ARRAY macros that rely on
palloc_array_extended and repalloc_array_extended with the NO_OOM
option, similarly to the existing MALLOC and REALLOC macros.
(Like those, they'll throw an error not return a NULL result for
oversize requests. This doesn't really fit into the regex code's
view of error handling, but it'll do for now. We can consider
whether to change that behavior in a non-security follow-up patch.)
I installed similar defenses in the colormap construction code.
It's not entirely clear whether integer overflow is possible
there, but analyzing the behavior in detail seems not worth
the trouble, as the risky spots are not in hot code paths.
I left a bunch of calls as-is after verifying that they can't
overflow given reasonable limits on nstates and narcs. Those
limits were enforced already via REG_MAX_COMPILE_SPACE, but
add commentary to document the interactions.
In passing, also fix a related edge case, which is that the
special color numbers used in LACON carcs could overflow the
"color" data type, if ncolors is close to MAX_COLOR.
In v14 and v15, the regex engine calls malloc() directly instead
of using palloc(), so MALLOC_ARRAY and REALLOC_ARRAY do likewise.
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
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
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.
Reported-by: Xint Code
Author: Michael Paquier <michael@paquier.xyz>
Backpatch-through: 14
Security: CVE-2026-6473
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 b1665bf01e. 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
Commit 16743db06 assumed that the CPUID instruction was always
available when the usual x86 symbols were defined. That is not the
case, so zero out the info rather than error out.
Reported-by: Jakob Egger <jakob@eggerapps.at>
Reported-by: Tobias Bussmann <t.bussmann@gmx.net>
Suggested-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/223EA201-A0E8-4A13-B220-EB903E8DF817@eggerapps.at
Commit 8d829f5a0 introduced a COALESCE wrapper around the
JSON_ARRAYAGG subquery so that JSON_ARRAY(query) returns '[]' rather
than NULL when the subquery yields no rows, per the SQL/JSON standard.
The empty-array Const used as the COALESCE fallback was, however,
built with typmod -1 and the type input function was likewise invoked
with typmod -1. As a result, any length restriction from the
RETURNING clause was silently bypassed on the empty-set path, while
the non-empty path enforced it via the JSON_ARRAYAGG coercion.
Build the empty-array Const using the typmod of the COALESCE's
non-empty argument, and pass that typmod to OidInputFunctionCall as
well so the value is length-checked at parse time. This makes the
empty-set and non-empty-set paths behave consistently.
Reported-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Author: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CAJTYsWXPYqa58YXrU+SQMVonsAhjLS46HNUMU=wO5zm9MgY3_g@mail.gmail.com
Error messages in check_publication_add_relation() previously reported
only the relation name when a table in an EXCEPT clause could not be
processed, which is ambiguous when the same name exists in multiple
schemas. Use schema-qualified names instead, consistent with other error
messages that reference relation names.
Author: Dilip Kumar <dilipbalaut@gmail.com>
Author: vignesh C <vignesh21@gmail.com>
Reviewed-by: shveta malik <shveta.malik@gmail.com>
Reviewed-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Discussion: https://postgr.es/m/CAFiTN-scG7b11Jsp+VoDRT8ZFE84eSKLcDsSB18dZ8AaP=R-mw@mail.gmail.com
When importing remote stats for a foreign table backed by a pre-v17
remote server, the query built/executed in this function has three NULL
placeholders for the range stats supported in v17 at the end of the
SELECT list. Previously, it included a trailing comma after the last
NULL, like "SELECT ..., NULL, NULL, NULL, FROM pg_catalog.pg_stats ...",
causing a syntax error on the remote server. Fix by removing the comma.
Oversight in commit 28972b6fc.
Author: Satya Narlapuram <satyanarlapuram@gmail.com>
Discussion: https://postgr.es/m/CAHg%2BQDdEE7wp1S60Fn9Kmna8KfdMo5Tu6dROLpMn_-EOUBKmWQ%40mail.gmail.com
remove_useless_groupby_columns() uses a relation's unique indexes to
prove that some GROUP BY columns are functionally dependent on others,
and so can be dropped from the GROUP BY clause. The match between
index columns and GROUP BY columns was done by attno alone, ignoring
two equality-relation issues.
A type may belong to multiple btree opfamilies whose notions of
equality differ. The record type, for instance, has record_ops
(per-field equality) and record_image_ops (bytewise equality). A
unique index under one opfamily does not prove uniqueness under the
equality used by GROUP BY when the SortGroupClause's eqop comes from a
different opfamily.
Likewise, since nondeterministic collations were introduced in PG 12,
two collations may disagree on equality, and a unique index under one
collation does not prove uniqueness under another.
In either case, rows that the index considers distinct can collapse
into a single GROUP BY group, taking ungrouped columns of differing
values with them, so the planner drops a column that is not in fact
functionally dependent and produces wrong results.
Fix by requiring, for each unique-index key column, that some GROUP BY
item on the same column has an eqop in the index's opfamily and a
collation that agrees on equality with the index's collation. This
mirrors the combined check relation_has_unique_index_for() applies to
join clauses.
This is a v18 regression: commit bd10ec529 extended
remove_useless_groupby_columns() from primary-key constraints to
arbitrary unique indexes. Before that, the function consulted only
primary keys, whose enforcement index is required by parse_utilcmd.c
to use the default opclass and the column's declared collation, so
neither mismatch could arise. Back-patch to v18 only.
Author: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: https://postgr.es/m/CAMbWs49t6uArWoTT-cHY+nhsi23nJJKcF9Xb9cYGzaZ9kNJ98g@mail.gmail.com
Backpatch-through: 18
Commit f76686ce7 added a walker that detects when a HAVING clause uses
a collation that conflicts with the GROUP BY's nondeterministic
collation, keeping such clauses in HAVING. The walker uses
exprInputCollation() to identify each ancestor's comparison collation,
but missed the simple-CASE case: parse analysis builds each WHEN as
OpExpr(CaseTestExpr op val), where CaseTestExpr is a placeholder for
the arg, while the actual arg expression sits at cexpr->arg, outside
the OpExpr that carries the comparison's inputcollid. A GROUP Var at
cexpr->arg was therefore visited with the WHEN's inputcollid absent
from the ancestor stack, the conflict went undetected, and the clause
was wrongly pushed to WHERE.
Fix by handling simple CASE explicitly: before walking cexpr->arg,
push every WHEN's inputcollid onto the ancestor stack so a GROUP Var
at the arg is checked against the same collations the WHEN comparisons
would apply. Then walk the WHEN bodies and defresult under the
unchanged stack, where their own collation contexts are picked up by
the default path.
Back-patch to v18 only; this fix extends the walker added by commit
f76686ce7 and inherits its dependency on the v18 RTE_GROUP mechanism.
Author: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CAHg+QDcqPdd=2V0PQ_oNYj50OUeqSqznqFaYtP3RdokLBDXBqw@mail.gmail.com
Backpatch-through: 18
afterTriggerInvokeEvents() may repalloc afterTriggers.query_stack
while firing trigger events, leaving any precomputed entry pointer
dangling. The loop body in AfterTriggerEndQuery() recomputes qs
after each afterTriggerInvokeEvents() call for that reason, but the
"all fired" break path exits without the recompute, and the
subsequent FireAfterTriggerBatchCallbacks(qs->batch_callbacks)
dereferences the freed pointer.
Fix by recomputing qs immediately before
FireAfterTriggerBatchCallbacks(), as the loop body already does
after each afterTriggerInvokeEvents() call.
The hazard was introduced in 34a3078629, which added the
qs->batch_callbacks dereference at this site.
Reported-by: Amul Sul <sulamul@gmail.com>
Author: Amul Sul <sulamul@gmail.com>
Reviewed-by: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/CAAJ_b95p6-qiVpE2Gpr=bUsNAqTcejD_rPgLnfjx9m=fo3Rf3Q@mail.gmail.com
Previously, InitializeProcessXLogLogicalInfo() was called before
ProcSignalInit(). This created a window where a process could miss a
signal barrier if it was issued between these two calls. As a result,
the process could fail to update its local XLogLogicalInfo cache,
leading to an inconsistent logical decoding state.
This commit fixes this by moving InitializeProcessXLogLogicalInfo()
after ProcSignalInit(). This ensures that the process is registered to
participate in signal barriers before its state is initialized,
preventing it from missing any state changes propagated during the
startup sequence.
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAD21AoBzdeSyLSSPM5E6ysN1r8qzp8u_BRmnLvuAp_S8QxS_fQ@mail.gmail.com
Discussion: https://postgr.es/m/CAD21AoBj+zKvgw_Q8gjr4YbKccW_uMe3OFQ5+KT246FHUuNXSQ@mail.gmail.com
The regression tests had a copy of the full error, detail, and hint
text in comments above each failing statement in the .sql files. This
is a maintenance hazard, so simplify to "-- ERROR", in line with
other tests.
Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/CANWCAZap26BRLwtd+A7GFDSD6-+C3F0NVdUGUAu2LUfvpOTy=w@mail.gmail.com
Fix spelling and grammar, turn an accidental duplicate errmsg into
errdetail, and remove an errposition that was not pointing at anything
relevant to the error.
Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Yuchen Li <liyuchen_xyz@163.com> (earlier version)
Discussion: https://postgr.es/m/CAJTYsWUvMT5uKOasPnm6-o9CrdXbRONiAYHTKJb7wx66LB8S1A@mail.gmail.com
Property graph element labels and label properties relied on a direct
systable scan when retrieving their object descriptions. These can be
simplified with get_catalog_object_by_oid(). This offers the benefit to
do a direct syscache lookup, if available.
The same logic will be used in a follow-up patch when retrieving the
object identity parts, applying the same rule across the board for these
object types.
Extracted from a larger patch by the author.
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Alex Guo <guo.alex.hengchen@gmail.com>
Discussion: https://postgr.es/m/aej1DkLwhyZWmtxJ@bdtpg
WAIT FOR LSN registers the current backend in shared memory before entering an
interruptible wait loop. Top-level abort and backend exit already call
WaitLSNCleanup(), but subtransaction abort did not. If an interrupt, such as
statement_timeout, occurred while waiting inside a savepoint, rolling back to
the savepoint left the backend marked as present in the WAIT FOR LSN heap.
Clean up WAIT FOR LSN state from AbortSubTransaction() as well, and add
a TAP test covering reuse of WAIT FOR LSN after a savepoint rollback.
Reported-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: https://postgr.es/m/CAJTYsWXDRwo-RVRaQgwxVcXgURVFeX8BKnijQrPiPcSCkDDX9A%40mail.gmail.com
Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Author: Xuneng Zhou <xunengzhou@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
The test for finding page verification failures in the logfiles
were missing the /m modifier to make sure it anchors to every
newline in the search space buffer, and not just the last one.
Spotted while adding a test for the recently reported issue with
excessive WAL for unlogged relations.
Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Reviewed-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: https://postgr.es/m/CAHg+QDeGrpZbNZdLjd_T4b43xKEEXZN0HGhkFm-1bkBdyzK7AQ@mail.gmail.com
The DataChecksumsWorker accepts cost_delay and cost_limit parameters
from pg_enable_data_checksums() so users can throttle the I/O caused
by enabling checksums. Due to the API for setting the cost parameters
changing between when the code was written, and when it was committed
the new cost update function call was omitted and thus the parameters
were silently ignored.
Fix by calling VacuumUpdateCosts() after assigning the parameters
(both during worker startup and on the runtime cost-update path), and
by leaving the page-cost weights at their GUC-controlled defaults.
Author: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: https://postgr.es/m/CAHg+QDeevH6aTyWdXYBJW0wOmfoZy66gDi5TfinK_dXeCrHQLg@mail.gmail.com
ProcessSingleRelationFork() unconditionally generated an FPI WAL
record for every page of every relation when enabling checksums.
Unlogged relations, which by definition never generate WAL for
data changes, were not exempt which generated excessive WAL to
be emitted.
Fix by guarding the FPI WAL record call with RelationNeedsWAL()
to avoid emitting WAL for unlogged main forks. Unlogged pages
are still dirtied to ensure the checksum is written to disk at
the next checkpoint. The init fork remains WAL-logged even for
unlogged relations, as it's needed on the standby to materialize
the relation after promotion (see ResetUnloggedRelations()).
Skipping init-fork WAL would leave the standby with a stale init
fork that, once copied to the main fork on promotion, would fail
checksum verification on every read of the unlogged relation.
A test which creates an unlogged table with an index, enables
checksums, promotes the standby, and verifies that the unlogged
relation and its indexes are still readable post-promotion has
been added.
Author: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: https://postgr.es/m/CAHg+QDeGrpZbNZdLjd_T4b43xKEEXZN0HGhkFm-1bkBdyzK7AQ@mail.gmail.com
Commit b3cf461b3c renamed --wal-directory to --wal-path but retained
the former as a silent alias. Per project policy, all options,
including deprecated ones, should be documented to assist users
transitioning between versions.
This patch restores --wal-directory to the documentation and --help
output.
Author: Amul Sul <sulamul@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/E1w3fZp-000gje-31%40gemulon.postgresql.org
get_tables_to_repack() and get_all_vacuum_rels() were including other
sessions' temporary tables in their output work list, causing REPACK,
CLUSTER and VACUUM FULL (when executed without a table list) to attempt
to acquire AccessExclusiveLock on them, potentially blocking for an
extended time. Fix by skipping other-session temp tables early, before
they are added to the list.
This issue is ancient, but there have been no complaints about it that I
know of, so I'm opting for not backpatching at present.
Author: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Discussion: https://postgr.es/m/0b555318-2bf2-46df-9377-09629a2a59db@uni-muenster.de
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.
Oversight in commit 8bf58c0d9.
Reported-by: Zhibai Song <songzhibai1234@gmail.com>
Diagnosed-by: Zhibai Song <songzhibai1234@gmail.com>
Author: Etsuro Fujita <etsuro.fujita@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Discussion: https://postgr.es/m/CAPmGK176y6JP017-Cn%2BhS9CEJx_6iVhRoYbAqzuLU4d8-XPPNg%40mail.gmail.com
Backpatch-through: 14
Commit 28d534e2ae introduced reform_tuple() with a fast path that
returns the source tuple verbatim when no dropped columns require fixing
up. I (Álvaro) failed to realize that this broke handling of columns
with a 'missingval' defined: after a VACUUM FULL, CLUSTER, or REPACK
operation, the catalogued missingval is thrown away, so the tuples are
no longer correct.
Fix by forcing the rewrite when the tuple is shorter than the tuple
descriptor.
Author: Satya Narlapuram <satyanarlapuram@gmail.com>
Discussion: https://postgr.es/m/CAHg+QDeoccU5CudrJpmSKZfKZ1gRMNY=5BxSC=JpHgkonzgcOw@mail.gmail.com
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
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
This function returns some value of enum HostsFileLoadResult,
but for reasons lost in the development process was declared to
return "int". Fix that, for clarity and so that our typedefs
collection tooling sees the typedef as used. Also fix the
variable that the sole call assigns into. Move the typedef
to the header file that declares load_hosts() to avoid creating
header dependency problems.
Discussion: https://postgr.es/m/359138.1777922557@sss.pgh.pa.us
expression_tree_mutator_impl() did not handle T_GraphPattern,
T_GraphElementPattern, and T_GraphPropertyRef. The corresponding
expression_tree_walker_impl() already handles all three node types.
This causes an "unrecognized node type" error whenever a GRAPH_TABLE
appeared in an expression tree.
While at it, also update raw_expression_tree_walker() and
expression_tree_walker() to handle missing nodes that may appear in
GraphPattern expression trees. When raw_expression_tree_walker() is
called, GraphElementPattern::labelexpr contains ColumnRefs instead of
GraphLabelRefs. Hence those are not handled in
raw_expression_tree_walker().
Author: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAHg%2BQDc97WFTSkXg%3Dg_ZAH8GnY2gJrvq72cs%2BYjqEAuZgXnkAQ%40mail.gmail.com
append_tuple_value_detail() constructed user-visible messages using
separately translated fragments such as ": ", ", ", and ".",. This
makes correct translation difficult or impossible in some languages.
Refactor append_tuple_value_detail() to move all punctuation and
sentence construction to the callers, which now use a single
translatable string with a %s placeholder for the tuple data.
Reported-by: David Rowley <dgrowleyml@gmail.com>
Author: vignesh C <vignesh21@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Zhijie Hou <houzj.fnst@fujitsu.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Discussion: https://postgr.es/m/227279.1775956328%40sss.pgh.pa.us#8f3a5f50543556c60cc5a13270cb7ba4
Discussion: https://postgr.es/m/CAApHDvohYOdrvhVxXzCJNX_GYMSWBfjTTtB6hgDauEtZ8Nar2A@mail.gmail.com
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.
Discussion: https://postgr.es/m/596c4f1c-f966-4512-b9c9-dd8fbcaf0928%40postgrespro.ru
Author: Alexey Makhmutov <a.makhmutov@postgrespro.ru>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
WAIT FOR LSN compares only the numeric LSN and has no notion of which
timeline a WAL record belongs to. There are many possible scenarios when
timeline-switching can break read-your-writes consistency. The proper
analysis and timeline support is possible in the next major release. Yet
just document the current behaviour.
Reported-by: Xuneng Zhou <xunengzhou@gmail.com>
Author: Alexander Korotkov <aekorotkov@gmail.com>
Add regression coverage for several WAIT FOR LSN edge cases.
First, cover fresh walreceiver shared-memory initialization after a
standby restart. Restart the standby while its upstream is down, so
RequestXLogStreaming() seeds writtenUpto/flushedUpto to the
segment-aligned receiveStart and the walreceiver cannot immediately
advance them. Verify that the seeded flush position is segment-aligned,
that replay can be ahead of it, and that standby_write/standby_flush
still succeed for an already-replayed LSN via the replay-position floor
in GetCurrentLSNForWaitType().
Second, add fencepost checks for the target <= currentLSN predicate.
With replay paused and walreceiver stopped, verify exact boundaries for
standby_replay using pg_last_wal_replay_lsn(), and for standby_flush
using pg_last_wal_receive_lsn(). Also verify that a waiter for
current + 1 sleeps while replay is paused and wakes with success once
new WAL is delivered and replay advances.
Finally, add a cascading-standby timeline-switch test. Start a waiter
on the downstream standby, promote its upstream, generate WAL on the new
timeline, and verify that the cascade follows the new timeline and the
wait completes successfully once replay reaches the target LSN.
Reported-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/1957514.1775526774%40sss.pgh.pa.us
Author: Alexander Korotkov <aekorotkov@gmail.com>
Author: Xuneng Zhou <xunengzhou@gmail.com>
