This practice avoids possible problems caused by non-default psql
options, such as disabling AUTOCOMMIT.
Author: Shinya Kato <Shinya11.Kato@oss.nttdata.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Discussion: https://postgr.es/m/96ff23a5d858ff72ca8e823a014d16fe@oss.nttdata.com
Backpatch-through: 13
The sizeof() call should reference buffer.data, because that's the
buffer we're reading data into, not the whole PGAlignedBuffer union.
This was introduced by 44cac93464, which replaced the simple buffer
with a PGAlignedBuffer field.
It's benign, because the buffer is the largest field of the union, so
the sizes are the same. But it's easy to trip over this in a patch, so
fix and backpatch. Commit 44cac93464 went into 12, but that's EOL.
Backpatch-through: 13
Discussion: https://postgr.es/m/928bdab1-6567-449f-98c4-339cd2203b87@vondra.me
We thought that this condition was unreachable in ExitPostmaster,
but actually it's possible if you have both a misconfigured locale
setting and some other mistake that causes PostmasterMain to bail
out before reaching its own check of pthread_is_threaded_np().
Given the lack of other reports, let's not ask for bug reports if
this occurs; instead just give the same hint as in PostmasterMain.
Bug: #18783
Reported-by: anani191181515@gmail.com
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/18783-d1873b95a59b9103@postgresql.org
Discussion: https://postgr.es/m/206317.1737656533@sss.pgh.pa.us
Backpatch-through: 13
This patch fixes two distinct errors that both ultimately trace
to commit 71d60e2aa, which added the ats_modifiedcols field.
The more severe error is that ats_modifiedcols wasn't accounted for
in afterTriggerAddEvent's scanning loop that looks for a pre-existing
duplicate AfterTriggerSharedData. Thus, a new event could be
incorrectly matched to an AfterTriggerSharedData that has a different
value of ats_modifiedcols, resulting in the wrong tg_updatedcols
bitmap getting passed to the trigger whenever it finally gets fired.
We'd not noticed because (a) few triggers consult tg_updatedcols,
and (b) we had no tests exercising a case where such a trigger was
called as an AFTER trigger. In the test case added by this commit,
contrib/lo's trigger fails to remove a large object when expected
because (without this fix) it thinks the LO OID column hasn't changed.
The other problem was introduced by commit ce5aaea8c, which copied the
modified-columns bitmap into trigger-related storage. It made a copy
for every trigger event, whereas what we really want is to make a new
copy only when we make a new AfterTriggerSharedData entry. (We could
imagine adding extra logic to reduce the number of bitmap copies still
more, but it doesn't look worthwhile at the moment.) In a simple test
of an UPDATE of 10000000 rows with a single AFTER trigger, this thinko
roughly tripled the amount of memory consumed by the pending-triggers
data structures, from 160446744 to 480443440 bytes.
Fixing the first problem requires introducing a bms_equal() call into
afterTriggerAddEvent's scanning loop, which is slightly annoying from
a speed perspective. However, getting rid of the excessive bms_copy()
calls from the second problem balances that out; overall speed of
trigger operations is the same or slightly better, in my tests.
Discussion: https://postgr.es/m/3496294.1737501591@sss.pgh.pa.us
Backpatch-through: 13
Most were introduced in the 17 timeframe. The ones in wparser_def.c are
very old.
I also changed "JSON path expression for column \"%s\" should return
single item without wrapper" to "JSON path expression for column \"%s\"
must return single item when no wrapper is requested" to avoid
ambiguity.
Backpatch to 17.
Crickets: https://postgr.es/m/202501131819.26ors7oouafu@alvherre.pgsql
In common cases, foreign keys are defined on the toplevel partitioned
table; but if instead one is defined on a partition and references a
partitioned table, and the referencing partition is detached, we would
examine the pg_constraint row on the partition being detached, and fail
to realize that the sub-constraints must be left alone. This causes the
ALTER TABLE DETACH process to fail with
ERROR: could not find ON INSERT check triggers of foreign key constraint NNN
This is similar but not quite the same as what was fixed by
53af9491a043. This bug doesn't affect branches earlier than 15, because
the detach procedure was different there, so we only backpatch down to
15.
Fix by skipping such modifying constraints that are children of other
constraints being detached.
Author: Amul Sul <sulamul@gmail.com>
Diagnosys-by: Sami Imseih <samimseih@gmail.com>
Discussion: https://postgr.es/m/CAAJ_b97GuPh6wQPbxQS-Zpy16Oh+0aMv-w64QcGrLhCOZZ6p+g@mail.gmail.com
The freshly-released 2025a version of tzdata has a refined estimate
for the longitude of Manila, changing their value for LMT in
pre-standardized-timezone days. This changes the output of one of
our test cases. Since we need to be able to run with system tzdata
files that may or may not contain this update, we'd better stop
making that specific test.
I switched it to use Asia/Singapore, which has a roughly similar UTC
offset. That LMT value hasn't changed in tzdb since 2003, so we can
hope that it's well established.
I also noticed that this set of make_timestamptz tests only exercises
zones east of Greenwich, which seems rather sad, and was not the
original intent AFAICS. (We've already changed these tests once
to stabilize their results across tzdata updates, cf 66b737cd9;
it looks like I failed to consider the UTC-offset-sign aspect then.)
To improve that, add a test with Pacific/Honolulu. That LMT offset
is also quite old in tzdb, so we'll cross our fingers that it doesn't
get improved.
Reported-by: Christoph Berg <cb@df7cb.de>
Discussion: https://postgr.es/m/Z46inkznCxesvDEb@msg.df7cb.de
Backpatch-through: 13
If a WaitEventSetWait() caller asks for multiple events, an already set
latch would previously prevent other events from being reported at the
same time. Now, we'll also poll the kernel for other events that would
fit in the caller's output buffer with a zero wait time. This policy
change doesn't affect callers that ask for only one event.
The main caller affected is the postmaster. If its latch is set
extremely frequently by backends launching workers and workers exiting,
we don't want it to handle only those jobs and ignore incoming client
connections.
Back-patch to 16 where the postmaster began using the API. The
fast-return policy changed here is older than that, but doesn't cause
any known problems in earlier releases.
Reported-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://postgr.es/m/Z1n5UpAiGDmFcMmd%40nathan
XLogPageRead() checks immediately for an invalid WAL record header on a
standby, to be able to handle the case of continuation records that need
to be read across two different sources. As written, the check was too
generic, applying to any target LSN. Based on an analysis by Kyotaro
Horiguchi, what really matters is to make sure that the page header is
checked when attempting to read a LSN at the boundary of a segment, to
handle the case of a continuation record that spawns across multiple
pages when dealing with multiple segments, as WAL receivers are spawned
they request WAL from the beginning of a segment. This fix has been
proposed by Kyotaro Horiguchi.
This could cause standbys to loop infinitely when dealing with a
continuation record during a timeline jump, in the case where the
contents of the record in the follow-up page are invalid.
Some regression tests are added to check such scenarios, able to
reproduce the original problem. In the test, the contents of a
continuation record are overwritten with junk zeros on its follow-up
page, and replayed on standbys. This is inspired by 039_end_of_wal.pl,
and is enough to show how standbys should react on promotion by not
being stuck. Without the fix, the test would fail with a timeout. The
test to reproduce the problem has been written by Alexander Kukushkin.
The original check has been introduced in 066871980183, for a similar
problem.
Author: Kyotaro Horiguchi, Alexander Kukushkin
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/CAFh8B=mozC+e1wGJq0H=0O65goZju+6ab5AU7DEWCSUA2OtwDg@mail.gmail.com
Backpatch-through: 13
This commit reverts 8f67f994e8ea (down to v13) and c3de0f9eed38 (down to
v17), as these are proving to not be completely correct regarding two
aspects:
- In v17 and newer branches, c3de0f9eed38's check for epoch handling is
incorrect, and does not correctly handle frozen epochs. A logic closer
to widen_snapshot_xid() should be used. The 2PC code should try to
integrate deeper with FullTransactionIds, 5a1dfde8334b being not enough.
- In v13 and newer branches, 8f67f994e8ea is a workaround for the real
issue, which is that we should not attempt CLOG lookups without reaching
consistency. This exists since 728bd991c3c4, and this is reachable with
ProcessTwoPhaseBuffer() called by restoreTwoPhaseData() at the beginning
of recovery.
Per discussion with Noah Misch.
Discussion: https://postgr.es/m/20250116010051.f3.nmisch@google.com
Backpatch-through: 13
We should run the expression subtrees of PartitionedRelPruneInfo
structs through fix_scan_expr. Failure to do so means that
AlternativeSubPlans within those expressions won't be cleaned up
properly, resulting in "unrecognized node type" errors since v14.
It seems fairly likely that at least some of the other steps done
by fix_scan_expr are important here as well, resulting in as-yet-
undetected bugs. Therefore, I've chosen to back-patch this to
all supported branches including v13, even though the known
symptom doesn't manifest in v13.
Per bug #18778 from Alexander Lakhin.
Discussion: https://postgr.es/m/18778-24cd399df6c806af@postgresql.org
These facilities were originally in the recovery TAP test
039_end_of_wal.pl. A follow-up bug fix with a TAP test doing similar
WAL manipulations requires them, and all these had better not be
duplicated due to their complexity. The routine names are tweaked to
use "wal" more consistently, similarly to the existing "advance_wal".
In v14 and v13, the new routines are moved to PostgresNode.pm.
039_end_of_wal.pl is updated to use the refactored routines, without
changing its coverage.
Reviewed-by: Alexander Kukushkin
Discussion: https://postgr.es/m/CAFh8B=mozC+e1wGJq0H=0O65goZju+6ab5AU7DEWCSUA2OtwDg@mail.gmail.com
Backpatch-through: 13
In the name of ABI stability (that is, to avoid a library major
version bump for libpq), libpq still exports a version of pqsignal()
that we no longer want to use ourselves. However, since that has
the same link name as the function exported by src/port/pqsignal.c,
there is a link ordering dependency determining which version will
actually get used by code that uses libpq as well as libpgport.a.
It now emerges that the wrong version has been used by pgbench and
psql since commit 06843df4a rearranged their link commands. This
can result in odd failures in pgbench with the -T switch, since its
SIGALRM handler will now not be marked SA_RESTART. psql may have
some edge-case problems in \watch, too.
Since we don't want to depend on link ordering effects anymore,
let's fix this in the same spirit as b6c7cfac8: use macros to change
the actual link names of the competing functions. We cannot change
legacy-pqsignal.c's exported name of course, so the victim has to be
src/port/pqsignal.c.
In master, rename its exported name to be pqsignal_fe in frontend or
pqsignal_be in backend. (We could perhaps have gotten away with using
the same symbol in both cases, but since the FE and BE versions now
work a little differently, it seems advisable to use different names.)
In back branches, rename to pqsignal_fe in frontend but keep it as
pqsignal in backend. The frontend change could affect third-party
code that is calling pqsignal from libpgport.a or libpgport_shlib.a,
but only if the code is compiled against port.h from a different minor
release than libpgport. Since we don't support using libpgport as a
shared library, it seems unlikely that there will be such a problem.
I left the backend symbol unchanged to avoid an ABI break for
extensions. This means that the link ordering hazard still exists
for any extension that links against libpq. However, none of our own
extensions use both pqsignal() and libpq, and we're not making things
any worse for third-party extensions that do.
Report from Andy Fan, diagnosis by Fujii Masao, patch by me.
Back-patch to all supported branches, as 06843df4a was.
Discussion: https://postgr.es/m/87msfz5qv2.fsf@163.com
The ecpg command includes code to warn about unsupported COPY FROM STDIN
statements in input files. However, since commit 3d009e45bd,
this functionality has been broken due to a bug introduced in that commit,
causing ecpg to fail to detect the statement.
This commit resolves the issue, restoring ecpg's ability to detect
COPY FROM STDIN and issue a warning as intended.
Back-patch to all supported versions.
Author: Ryo Kanbayashi
Reviewed-by: Hayato Kuroda, Tom Lane
Discussion: https://postgr.es/m/CANOn0Ez_t5uDCUEV8c1YORMisJiU5wu681eEVZzgKwOeiKhkqQ@mail.gmail.com
If a new catalog tuple is inserted that belongs to a catcache list
entry, and cache invalidation happens while the list entry is being
built, the list entry might miss the newly inserted tuple.
To fix, change the way we detect concurrent invalidations while a
catcache entry is being built. Keep a stack of entries that are being
built, and apply cache invalidation to those entries in addition to
the real catcache entries. This is similar to the in-progress list in
relcache.c.
Back-patch to all supported versions.
Reviewed-by: Noah Misch
Discussion: https://www.postgresql.org/message-id/2234dc98-06fe-42ed-b5db-ac17384dc880@iki.fi
This function expects an "int64" as result and stores the number of
pages to add to the index scan bitmap as an "int", multiplying its final
result by 10. For a relation large enough, this can theoretically
overflow if counting more than (INT32_MAX / 10) pages, knowing that the
number of pages is upper-bounded by MaxBlockNumber.
To avoid the overflow, this commit redefines "totalpages", used to
calculate the result, to be an "int64" rather than an "int".
Reported-by: Evgeniy Gorbanyov
Author: James Hunter
Discussion: https://www.postgresql.org/message-id/07704817-6fa0-460c-b1cf-cd18f7647041@basealt.ru
Backpatch-through: 13
Commit 27a1f8d108 missed updating the max HBA option count to
account for the new option added. Fix by bumping the counter
and adjust the relevant comment to match. Backpatch down to
all supported branches like the erroneous commit.
Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/286764.1736697356@sss.pgh.pa.us
Backpatch-through: v13
When deparsing a JsonExpr, variable names in the PASSING clause were
not quoted. However, since they are parsed as ColLabel tokens, some
variable names require double quotes to ensure that they are properly
interpreted. Fix by using quote_identifier() in the deparsing code.
This oversight was limited to the SQL/JSON query functions
JSON_EXISTS(), JSON_QUERY(), and JSON_VALUE().
Back-patch to v17, where these functions were added.
Dean Rasheed, reviewed by Tom Lane.
Discussion: https://postgr.es/m/CAEZATCXTpAS%3DncfLNTZ7YS6O5puHeLg_SUYAit%2Bcs7wsrd9Msg%40mail.gmail.com
When deparsing an XMLTABLE() expression, XML namespace names were not
quoted. However, since they are parsed as ColLabel tokens, some names
require double quotes to ensure that they are properly interpreted.
Fix by using quote_identifier() in the deparsing code.
Back-patch to all supported versions.
Dean Rasheed, reviewed by Tom Lane.
Discussion: https://postgr.es/m/CAEZATCXTpAS%3DncfLNTZ7YS6O5puHeLg_SUYAit%2Bcs7wsrd9Msg%40mail.gmail.com
PLy_spi_execute_plan (PLyPlan.execute) and PLy_cursor_plan
(plpy.cursor) use PLy_output_convert to convert Python values
into Datums that can be passed to the query-to-execute. But they
failed to pay much attention to its warning that it can leave "cruft
generated along the way" behind. Repeated use of these methods can
result in a substantial memory leak for the duration of the calling
plpython function.
To fix, make a temporary memory context to invoke PLy_output_convert
in. This also lets us get rid of the rather fragile code that was
here for retail pfree's of the converted Datums. Indeed, we don't
need the PLyPlanObject.values field anymore at all, though I left it
in place in the back branches in the name of ABI stability.
Mat Arye and Tom Lane, per report from Mat Arye. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/CADsUR0DvVgnZYWwnmKRK65MZg7YLUSTDLV61qdnrwtrAJgU6xw@mail.gmail.com
The ldapscheme option was missed when inspecing the HbaLine for
assembling rows for the pg_hba_file_rules function. Backpatch
to all supported versions.
Author: Laurenz Albe <laurenz.albe@cybertec.at>
Reported-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Bug: 18769
Discussion: https://postgr.es/m/18769-dd8610cbc0405172@postgresql.org
Backpatch-through: v13
66c0185a3 gave the planner the ability to have union child queries
provide the union planner with pre-sorted input so that UNION queries
could be more efficiently implemented using Merge Append.
That commit overlooked checking that the UNION target list and the union
child target list's types all match. In some corner cases, this could
result in the planner producing sorts using the sort operator of the
top-level UNION's target list type rather than of the union child's
target list's type. The implications of this range from silently
working correctly, despite using the wrong sort operator all the way up
to a segmentation fault.
Here we fix by adjusting the planner so it makes no attempt to have the
subquery produce pre-sorted results when the data type of the UNION
target list and the types from the subquery target list don't match
exactly.
Backpatch to 17, where 66c0185a3 was introduced.
Reported-by: Jason Smith <dqetool@126.com>
Diagnosed-by: Tom Lane <tgl@sss.pgh.pa.us>
Bug: 18764
Discussion: https://postgr.es/m/18764-63ad667ea26e877a%40postgresql.org
Backpatch-through: 17
This error message stated the privileges required to add a member
to a group even if the user was trying to drop a member:
postgres=> alter group a drop user b;
ERROR: permission denied to alter role
DETAIL: Only roles with the ADMIN option on role "a" may add members.
Since the required privileges for both operations are the same, we
can fix this by modifying the message to mention both adding and
dropping members:
postgres=> alter group a drop user b;
ERROR: permission denied to alter role
DETAIL: Only roles with the ADMIN option on role "a" may add or drop members.
Author: ChangAo Chen
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/tencent_FAA0D00E3514AAF0BBB6322542A6094FEF05%40qq.com
Backpatch-through: 16
The originally submitted code (using bit masking) was correct when the
number of slots was restricted to be a power of two -- but that
limitation was removed during development that led to commit
53c2a97a9266, which made the bank selection code incorrect. This led to
always using a smaller number of banks than available. Change said code
to use integer modulo instead, which works correctly with an arbitrary
number of banks.
It's likely that we could improve on this to avoid runtime use of
integer division. But with this change we're, at least, not wasting
memory on unused banks, and more banks mean less contention, which is
likely to have a much higher performance impact than a single
instruction's latency.
Author: Yura Sokolov <y.sokolov@postgrespro.ru>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/9444dc46-ca47-43ed-9058-89c456316306@postgrespro.ru
walmethods.c used off_t to navigate around a pg_wal.tar file that could
exceed 2GB, which doesn't work on Windows and would fail with misleading
errors. Use pgoff_t instead.
Back-patch to all supported branches.
Author: Davinder Singh <davinder.singh@enterprisedb.com>
Reported-by: Jakub Wartak <jakub.wartak@enterprisedb.com>
Discussion: https://postgr.es/m/CAKZiRmyM4YnokK6Oenw5JKwAQ3rhP0YTz2T-tiw5dAQjGRXE3Q%40mail.gmail.com
Change our ftruncate() macro to use the 64-bit variant of chsize(), and
add a new macro to redirect lseek() to _lseeki64().
Back-patch to all supported releases, in preparation for a bug fix.
Tested-by: Davinder Singh <davinder.singh@enterprisedb.com>
Discussion: https://postgr.es/m/CAKZiRmyM4YnokK6Oenw5JKwAQ3rhP0YTz2T-tiw5dAQjGRXE3Q%40mail.gmail.com
Commit 66aaabe7 (branches 13 - 17 only) was not acceptable to the Oracle
Developer Studio compiler on build farm animal wrasse. It accidentally
used a C++ style return statement to wrap a void function. None of the
usual compilers complained, but it is right, that is not allowed in C.
Fix.
Reported-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/Z33vgfVgvOnbFLN9%40paquier.xyz
It's possible that external code is calling smgrtruncate(). Any
external callers might like to consider the recent changes to
RelationTruncate(), but commit 38c579b0 should not have changed the
function prototype in the back-branches, per ABI stability policy.
Restore smgrtruncate()'s traditional argument list in the back-branches,
but make it a wrapper for a new function smgrtruncate2(). The three
callers in core can use smgrtruncate2() directly. In master (18-to-be),
smgrtruncate2() is effectively renamed to smgrtruncate(), so this wart
is cleaned up.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKG%2BThae6x6%2BjmQiuALQBT2Ae1ChjMh1%3DkMvJ8y_SBJZrvA%40mail.gmail.com
Slightly faulty logic in the original jsonb code (commit d9134d0a355)
results in an empty top level array sorting less than a json null. We
can't change the sort order now since it would affect btree indexes over
jsonb, so document the anomaly.
Backpatch to all live branches (13 .. 17)
In master, also add a code comment noting the anomaly.
Reported-by: Yan Chengpen
Reviewed-by: Jian He
Discussion: https://postgr.es/m/OSBPR01MB45199DD8DA2D1CECD50518188E272@OSBPR01MB4519.jpnprd01.prod.outlook.com
When looking up statistical data about an expression, we do not need
to concern ourselves with the outer joins that could null the
Vars/PHVs contained in the expression. Accounting for nullingrels in
the expression could cause estimate_num_groups to count the same Var
multiple times if it's marked with different nullingrels. This is
incorrect, and could lead to "ERROR: corrupt MVNDistinct entry" when
searching for multivariate n-distinct.
Furthermore, the nullingrels could prevent us from matching an
expression to expressional index columns or to the expressions in
extended statistics, leading to inaccurate estimates.
To fix, strip out all the nullingrels from the expression before we
look up statistical data about it. There is one ensuing plan change
in the regression tests, but it looks reasonable and does not
compromise its original purpose.
This patch could result in plan changes, but it fixes an actual bug,
so back-patch to v16 where the outer-join-aware-Var infrastructure was
introduced.
Author: Richard Guo
Discussion: https://postgr.es/m/CAMbWs4-2Z4k+nFTiZe0Qbu5n8juUWenDAtMzi98bAZQtwHx0-w@mail.gmail.com
pgoutput caches the attribute map of a relation, that is free()'d only
when validating a RelationSyncEntry. However, this code path is not
taken when calling any of the SQL functions able to do some logical
decoding, like pg_logical_slot_{get,peek}_changes(), leaking some memory
into CacheMemoryContext on repeated calls.
To address this, a relation's attribute map is allocated in
PGOutputData's cachectx, free()'d at the end of the execution of these
SQL functions when logical decoding ends. This is available down to 15.
v13 and v14 have a similar leak, which will be dealt with later.
Reported-by: Masahiko Sawada
Author: Vignesh C
Reviewed-by: Hou Zhijie
Discussion: https://postgr.es/m/CAD21AoDkAhQVSukOfH3_reuF-j4EU0-HxMqU3dU+bSTxsqT14Q@mail.gmail.com
Discussion: https://postgr.es/m/CALDaNm1hewNAsZ_e6FF52a=9drmkRJxtEPrzCB6-9mkJyeBBqA@mail.gmail.com
Backpatch-through: 15
At the beginning of recovery, an orphaned two-phase file in an epoch
different than the one defined in the checkpoint record could not be
removed based on the assumptions that AdjustToFullTransactionId() relies
on, assuming that all files would be either from the current epoch or
from the previous epoch.
If the checkpoint epoch was 0 while the 2PC file was orphaned and in the
future, AdjustToFullTransactionId() would underflow the epoch used to
build the 2PC file path. In non-assert builds, this would create a
WARNING message referring to a 2PC file with an epoch of "FFFFFFFF" (or
UINT32_MAX), as an effect of the underflow calculation, leaving the
orphaned file around.
Some tests are added with dummy 2PC files in the past and the future,
checking that these are properly removed.
Issue introduced by 5a1dfde8334b, that has switched two-phase state
files to use FullTransactionIds.
Reported-by: Vitaly Davydov
Author: Michael Paquier
Reviewed-by: Vitaly Davydov
Discussion: https://postgr.es/m/13b5b6-676c3080-4d-531db900@47931709
Backpatch-through: 17
Before 728bd991c3c4, that has improved the support for 2PC files during
recovery, the initial logic scanning files in pg_twophase was done so as
files in the future of the transaction ID horizon were checked first,
followed by a check if a transaction ID is aborted or committed which
could involve a pg_xact lookup. After this commit, these checks have
been done in reverse order.
Files detected as in the future do not have a state that can be checked
in pg_xact, hence this caused recovery to fail abruptly should an
orphaned 2PC file in the future of the transaction ID horizon exist in
pg_twophase at the beginning of recovery.
A test is added to check for this scenario, using an empty 2PC with a
transaction ID large enough to be in the future when running the test.
This test is added in 16 and older versions for now. 17 and newer
versions are impacted by a second bug caused by the addition of the
epoch in the 2PC file names. An equivalent test will be added in these
branches in a follow-up commit, once the second set of issues reported
are fixed.
Author: Vitaly Davydov, Michael Paquier
Discussion: https://postgr.es/m/11e597-676ab680-8d-374f23c0@145466129
Backpatch-through: 13
Cause parallel workers to not check datallowconn, rolcanlogin, and
ACL_CONNECT privileges. The leader already checked these things
(except for rolcanlogin which might have been checked for a different
role). Re-checking can accomplish little except to induce unexpected
failures in applications that might not even be aware that their query
has been parallelized. We already had the principle that parallel
workers rely on their leader to pass a valid set of authorization
information, so this change just extends that a bit further.
Also, modify the ReservedConnections, datconnlimit and rolconnlimit
logic so that these limits are only enforced against regular backends,
and only regular backends are counted while checking if the limits
were already reached. Previously, background processes that had an
assigned database or role were subject to these limits (with rather
random exclusions for autovac workers and walsenders), and the set of
existing processes that counted against each limit was quite haphazard
as well. The point of these limits, AFAICS, is to ensure the
availability of PGPROC slots for regular backends. Since all other
types of processes have their own separate pools of PGPROC slots, it
makes no sense either to enforce these limits against them or to count
them while enforcing the limit.
While edge-case failures of these sorts have been possible for a
long time, the problem got a good deal worse with commit 5a2fed911
(CVE-2024-10978), which caused parallel workers to make some of these
checks using the leader's current role where before we had used its
AuthenticatedUserId, thus allowing parallel queries to fail after
SET ROLE. The previous behavior was fairly accidental and I have
no desire to return to it.
This patch includes reverting 73c9f91a1, which was an emergency hack
to suppress these same checks in some cases. It wasn't complete,
as shown by a recent bug report from Laurenz Albe. We can also revert
fd4d93d26 and 492217301, which hacked around the same problems in one
regression test.
In passing, remove the special case for autovac workers in
CheckMyDatabase; it seems cleaner to have AutoVacWorkerMain pass
the INIT_PG_OVERRIDE_ALLOW_CONNS flag, now that that does what's
needed.
Like 5a2fed911, back-patch to supported branches (which sadly no
longer includes v12).
Discussion: https://postgr.es/m/1808397.1735156190@sss.pgh.pa.us
The need for this was missed in commit 93db6cbda, with the result
being that if we launch a slotsync worker it would consume one of
the PGPROCs in the max_connections pool. That could lead to inability
to launch the worker, or to subsequent failures of connection requests
that should have succeeded according to the configured settings.
Rather than create some one-off infrastructure to support this,
let's group the slotsync worker with the existing autovac launcher
in a new category of "special worker" processes. These are kind of
like auxiliary processes, but they cannot use that infrastructure
because they need to be able to run transactions.
For the moment, make these processes share the PGPROC freelist
used for autovac workers (which previously supplied the autovac
launcher too). This is partly to avoid an ABI change in v17,
and partly because it seems silly to have a freelist with
at most two members. This might be worth revisiting if we grow
enough workers in this category.
Tom Lane and Hou Zhijie. Back-patch to v17.
Discussion: https://postgr.es/m/1808397.1735156190@sss.pgh.pa.us
These two platforms have a remarkably tight default limit on the
number of SysV semaphores in the system: SEMMNS is only 60
out-of-the-box. Unless manual action is taken to raise that,
we'll only be able to allocate 3 sets of 16 usable semaphores
each, leading to initdb setting max_connections to just 20.
That's problematic because the core regression tests expect
to be able to launch 20 concurrent sessions, leaving us with
no headroom. This seems to be the cause of intermittent
buildfarm failures on some machines.
While there's no getting around the fact that you'd better raise
SEMMNS for production use on these platforms, it does seem desirable
for "make check" to pass reliably without that. We can make that
happen, at least for awhile longer, with two small changes:
* Change sysv_sema.c's SEMAS_PER_SET to 19, so that we can eat up
all of the available semas not just most of them.
* Change initdb to make the smallest max_connections value it will
consider be 25 not 20.
This is a back-patch of recent HEAD commit 38da05346 into v17.
The motivation for doing this now is that an upcoming bug-fix
patch will give the new-in-17 slotsync worker process its own
reserved PGPROC and hence also semaphore. With that patch but
without this change, v17 would fail to start at all under the
default SEMMNS on these platforms.
Discussion: https://postgr.es/m/db2773a2-aca0-43d0-99c1-060efcd9954e@gmail.com
Discussion: https://postgr.es/m/1808397.1735156190@sss.pgh.pa.us
Commit aac2c9b4fde889d13f859c233c2523345e72d32b mandated such locking
and attempted to fulfill that mandate, but it missed REASSIGN OWNED.
Hence, it remained possible to lose VACUUM's inplace update of
datfrozenxid if a REASSIGN OWNED processed that database at the same
time. This didn't affect the other inplace-updated catalog, pg_class.
For pg_class, REASSIGN OWNED calls ATExecChangeOwner() instead of the
generic AlterObjectOwner_internal(), and ATExecChangeOwner() fulfills
the locking mandate.
Like in GRANT, implement this by following the locking protocol for any
catalog subject to the generic AlterObjectOwner_internal(). It would
suffice to do this for IsInplaceUpdateOid() catalogs only. Back-patch
to v13 (all supported versions).
Kirill Reshke. Reported by Alexander Kukushkin.
Discussion: https://postgr.es/m/CAFh8B=mpKjAy4Cuun-HP-f_vRzh2HSvYFG3rhVfYbfEBUhBAGg@mail.gmail.com
This fixes "unresolved external symbol" errors with extensions that
use functions from libpgport that need special CFLAGS to
compile. Currently, that includes the CRC-32 functions.
Commit 2571c1d5cc did this for libcommon, but I missed that libpqport
has the same issue.
Reported-by: Tom Lane
Backpatch-through: 16, where Meson was introduced
Discussion: https://www.postgresql.org/message-id/CAOdR5yF0krWrxycA04rgUKCgKugRvGWzzGLAhDZ9bzNv8g0Lag@mail.gmail.com
Despite the best efforts of commit 0e5c82380, we're still seeing
occasional failures of postgres_fdw's query_cancel test in the
buildfarm. Investigation suggests that its 100ms timeout is
still not enough to reliably ensure that the remote side starts
the query before receiving the cancel request --- and if it
hasn't, it will just discard the request because it's idle.
We discussed allowing a cancel request to kill the next-received
query, but that would have wide and perhaps unpleasant side-effects.
What seems safer is to make postgres_fdw do what a human user would
likely do, which is issue another cancel request if the first one
didn't seem to do anything. We'll keep the same overall 30 second
grace period before concluding things are broken, but issue additional
cancel requests after 1 second, then 2 more seconds, then 4, then 8.
(The next one in series is 16 seconds, but we'll hit the 30 second
timeout before that.)
Having done that, revert the timeout in query_cancel.sql to 10 ms.
That will still be enough on most machines, most of the time, for
the remote query to start; but now we're intentionally risking the
race condition occurring sometimes in the buildfarm, so that the
repeat-cancel code path will get some testing.
As before, back-patch to v17. We might eventually contemplate
back-patching this further, and/or adding similar logic to dblink.
But given the lack of field complaints to date, this feels like
mostly an exercise in test case stabilization, so v17 is enough.
Discussion: https://postgr.es/m/colnv3lzzmc53iu5qoawynr6qq7etn47lmggqr65ddtpjliq5d@glkveb4m6nop
The pgoutput module caches publication names in a list and frees it upon
invalidation. However, the code forgot to free the actual publication
names within the list elements, as publication names are pstrdup()'d in
GetPublication(). This would cause memory to leak in
CacheMemoryContext, bloating it over time as this context is not
cleaned.
This is a problem for WAL senders running for a long time, as an
accumulation of invalidation requests would bloat its cache memory
usage. A second case, where this leak is easier to see, involves a
backend calling SQL functions like pg_logical_slot_{get,peek}_changes()
which create a new decoding context with each execution. More
publications create more bloat.
To address this, this commit adds a new memory context within the
logical decoding context and resets it each time the publication names
cache is invalidated, based on a suggestion from Amit Kapila. This
ensures that the lifespan of the publication names aligns with that of
the logical decoding context.
Contrary to the HEAD-only commit f0c569d71515 that has changed
PGOutputData to track this new child memory context, the context is
tracked with a static variable whose state is reset with a MemoryContext
reset callback attached to PGOutputData->context, so as ABI
compatibility is preserved in stable branches. This approach is based
on an suggestion from Amit Kapila.
Analyzed-by: Michael Paquier, Jeff Davis
Author: Masahiko Sawada
Reviewed-by: Amit Kapila, Michael Paquier, Euler Taveira, Hou Zhijie
Discussion: https://postgr.es/m/Z0khf9EVMVLOc_YY@paquier.xyz
Backpatch-through: 13
GetSnapshotData() set TransactionXmin = MyProc->xmin, but when
SnapshotResetXmin() advanced MyProc->xmin, it did not advance
TransactionXmin correspondingly. That meant that TransactionXmin could
be older than MyProc->xmin, and XIDs between than TransactionXmin and
the real MyProc->xmin could be vacuumed away. One known consequence is
in pg_subtrans lookups: we might try to look up the status of an XID
that was already truncated away.
Back-patch to all supported versions.
Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/d27a046d-a1e4-47d1-a95c-fbabe41debb4@iki.fi
RelationTruncate() does three things, while holding an
AccessExclusiveLock and preventing checkpoints:
1. Logs the truncation.
2. Drops buffers, even if they're dirty.
3. Truncates some number of files.
Step 2 could previously be canceled if it had to wait for I/O, and step
3 could and still can fail in file APIs. All orderings of these
operations have data corruption hazards if interrupted, so we can't give
up until the whole operation is done. When dirty pages were discarded
but the corresponding blocks were left on disk due to ERROR, old page
versions could come back from disk, reviving deleted data (see
pgsql-bugs #18146 and several like it). When primary and standby were
allowed to disagree on relation size, standbys could panic (see
pgsql-bugs #18426) or revive data unknown to visibility management on
the primary (theorized).
Changes:
* WAL is now unconditionally flushed first
* smgrtruncate() is now called in a critical section, preventing
interrupts and causing PANIC on file API failure
* smgrtruncate() has a new parameter for existing fork sizes,
because it can't call smgrnblocks() itself inside a critical section
The changes apply to RelationTruncate(), smgr_redo() and
pg_truncate_visibility_map(). That last is also brought up to date with
other evolutions of the truncation protocol.
The VACUUM FileTruncate() failure mode had been discussed in older
reports than the ones referenced below, with independent analysis from
many people, but earlier theories on how to fix it were too complicated
to back-patch. The more recently invented cancellation bug was
diagnosed by Alexander Lakhin. Other corruption scenarios were spotted
by me while iterating on this patch and earlier commit 75818b3a.
Back-patch to all supported releases.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reported-by: rootcause000@gmail.com
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/18146-04e908c662113ad5%40postgresql.org
Discussion: https://postgr.es/m/18426-2d18da6586f152d6%40postgresql.org
Consistently reset so->scanBehind at the beginning of nbtree array
advancement, even during sktrig_required=false calls (calls where array
advancement is triggered by an unsatisfied non-required array scan key).
Otherwise, it's possible for queries to fail to return all relevant
tuples to the scan given a low-order required scan key that was
previously deemed "satisfied" by a truncated high key attribute value.
This only happened at the point where a later non-required array scan
key needed to be "advanced" once on the next leaf page (that is, once
the right sibling of the truncated high key page was reached).
The underlying issue was that later code within _bt_advance_array_keys
assumed that the so->scanBehind flag must have been set using the
current page's high key (not the previous page's high key). Any later
successful recheck call to _bt_check_compare would therefore spuriously
be prevented from making _bt_advance_array_keys return true, based on
the faulty belief that the truncated attribute must be from the scan's
current tuple (i.e. the non-pivot tuple at the start of the next page).
_bt_advance_array_keys would return false for the tuple, ultimately
resulting in _bt_checkkeys failing to return a matching tuple.
Oversight in commit 5bf748b8, which enhanced nbtree ScalarArrayOp
execution.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WzkJKncfqyAUTeuB5GgRhT1vhsWO2q11dbZNqKmvjopP_g@mail.gmail.com
Backpatch: 17-, where commit 5bf748b8 first appears.
