Commit Graph

47779 Commits

Author SHA1 Message Date
Michael Paquier ddded779a7 Fix assertion failure with PL/Python exceptions
PLy_elog() was not able to handle correctly cases where a SPI called
failed, which would fill in a DETAIL string able to trigger an
assertion.  We may want to improve this infrastructure so as it is able
to provide any extra detail information provided by an error stack, but
this is left as a future improvement as it could impact existing error
stacks and any applications that depend on them.  For now, the assertion
is removed and a regression test is added to cover the case of a failure
with a detail string.

This problem exists since 2bd78eb8d5, so backpatch all the way down
with tweaks to the regression tests output added where required.

Author: Alexander Lakhin
Discussion: https://postgr.es/m/18070-ab9c171cbf4ebb0f@postgresql.org
Backpatch-through: 11
2023-09-19 08:31:31 +09:00
Tom Lane db00be6d78 Don't crash if cursor_to_xmlschema is used on a non-data-returning Portal.
cursor_to_xmlschema() assumed that any Portal must have a tupDesc,
which is not so.  Add a defensive check.

It's plausible that this mistake occurred because of the rather
poorly chosen name of the lookup function SPI_cursor_find(),
which in such cases is returning something that isn't very much
like a cursor.  Add some documentation to try to forestall future
errors of the same ilk.

Report and patch by Boyu Yang (docs changes by me).  Back-patch
to all supported branches.

Discussion: https://postgr.es/m/dd343010-c637-434c-a8cb-418f53bda3b8.yangboyu.yby@alibaba-inc.com
2023-09-18 14:27:47 -04:00
Tom Lane a374f6c616 Track nesting depth correctly when drilling down into RECORD Vars.
expandRecordVariable() failed to adjust the parse nesting structure
correctly when recursing to inspect an outer-level Var.  This could
result in assertion failures or core dumps in corner cases.

Likewise, get_name_for_var_field() failed to adjust the deparse
namespace stack correctly when recursing to inspect an outer-level
Var.  In this case the likely result was a "bogus varno" error
while deparsing a view.

Per bug #18077 from Jingzhou Fu.  Back-patch to all supported
branches.

Richard Guo, with some adjustments by me

Discussion: https://postgr.es/m/18077-b9db97c6e0ab45d8@postgresql.org
2023-09-15 17:01:26 -04:00
Tom Lane 479b99125d Fix get_expr_result_type() to find field names for RECORD Consts.
This is a back-patch of commit d57534740 ("Fix EXPLAIN of SEARCH
BREADTH FIRST with a constant initial value") into pre-v14 branches.
At the time I'd thought it was not needed in branches that lack the
SEARCH/CYCLE feature, but that was just a failure of imagination.
It's possible to demonstrate "record type has not been registered"
failures in older branches too, during deparsing of views that contain
references to fields of composite constants.

Back-patch only the code changes, as the test cases added by d57534740
all require SEARCH/CYCLE syntax.  A suitable test case will be added
in the upcoming fix for bug #18077.

Discussion: https://postgr.es/m/17644-3bd1f3036d6d7a16@postgresql.org
Discussion: https://postgr.es/m/3607145.1694803130@sss.pgh.pa.us
2023-09-15 16:39:27 -04:00
Tom Lane ece1154f4c Allow extracting fields from a ROW() expression in more cases.
Teach get_expr_result_type() to manufacture a tuple descriptor directly
from a RowExpr node.  If the RowExpr has type RECORD, this is the only
way to get a tupdesc for its result, since even if the rowtype has been
blessed, we don't have its typmod available at this point.  (If the
RowExpr has some named composite type, we continue to let the existing
code handle it, since the RowExpr might well not have the correct column
names embedded in it.)

This fixes assorted corner cases illustrated by the added regression
tests.

This is a back-patch of the v13-era commit 8b7a0f1d1 into previous
branches.  At the time I'd judged it not important enough to back-patch,
but the upcoming fix for bug #18077 includes a test case that depends
on this working correctly; and 8b7a0f1d1 has now aged long enough to
have good confidence that it won't break anything.

Discussion: https://postgr.es/m/10872.1572202006@sss.pgh.pa.us
Discussion: https://postgr.es/m/3607145.1694803130@sss.pgh.pa.us
2023-09-15 16:20:08 -04:00
Michael Paquier bddbbdf99b Revert "Improve error message on snapshot import in snapmgr.c"
This reverts commit a0d87bcd9b, following a remark from Andres Frend
that the new error can be triggered with an incorrect SET TRANSACTION
SNAPSHOT command without being really helpful for the user as it uses
the internal file name.

Discussion: https://postgr.es/m/20230914020724.hlks7vunitvtbbz4@awork3.anarazel.de
Backpatch-through: 11
2023-09-14 16:00:47 +09:00
Michael Paquier a4cef3384d Improve error message on snapshot import in snapmgr.c
When a snapshot file fails to be read in ImportSnapshot(), it would
issue an ERROR as "invalid snapshot identifier" when opening a stream
for it in read-only mode.  This error message is reworded to be the same
as all the other messages used in this case on failure, which is useful
when debugging this area.

Thinko introduced by bb446b689b where snapshot imports have been
added.  A backpatch down to 11 is done as this can improve any work
related to snapshot imports in older branches.

Author: Bharath Rupireddy
Reviewed-by: Daniel Gustafsson
Discussion: https://postgr.es/m/CALj2ACWmr=3KdxDkm8h7Zn1XxBoF6hdzq8WQyMn2y1OL5RYFrg@mail.gmail.com
Backpatch-through: 11
2023-09-14 10:30:37 +09:00
Thomas Munro 6ae57f190e Fix exception safety bug in typcache.c.
If an out-of-memory error was thrown at an unfortunate time,
ensure_record_cache_typmod_slot_exists() could leak memory and leave
behind a global state that produced an infinite loop on the next call.

Fix by merging RecordCacheArray and RecordIdentifierArray into a single
array.  With only one allocation or re-allocation, there is no
intermediate state.

Back-patch to all supported releases.

Reported-by: "James Pang (chaolpan)" <chaolpan@cisco.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/PH0PR11MB519113E738814BDDA702EDADD6EFA%40PH0PR11MB5191.namprd11.prod.outlook.com
2023-09-13 14:52:34 +12:00
Amit Kapila feb4e218e5 Fix uninitialized access to InitialRunningXacts during decoding after ERROR.
The transactions and subtransactions array that was allocated under
snapshot builder memory context and recorded during decoding was not
cleared in case of errors. This can result in an assertion failure if we
attempt to retry logical decoding within the same session. To address this
issue, we register a callback function under the snapshot builder memory
context to clear the recorded transactions and subtransactions array along
with the context.

This problem doesn't exist in PG16 and HEAD as instead of using
InitialRunningXacts, we added the list of transaction IDs and
sub-transaction IDs, that have modified catalogs and are running during
snapshot serialization, to the serialized snapshot (see commit 7f13ac8123).

Author: Hou Zhijie
Reviewed-by: Amit Kapila
Backpatch-through: 11
Discussion: http://postgr.es/m/18055-ab3beed9f4b7b7d6@postgresql.org
2023-09-12 09:36:56 +05:30
Bruce Momjian 0aeadb4f79 doc: remove mention of backslash doubling in strings
Reported-by: Laurenz Albe

Discussion: https://postgr.es/m/0b03f91a875fb44182f5bed9e1d404ed6d138066.camel@cybertec.at

Author: Laurenz Albe

Backpatch-through: 11
2023-09-08 17:25:14 -04:00
Michael Paquier dbd1a06c97 pg_basebackup: Generate valid temporary slot names under PQbackendPID()
pgbouncer can cause PQbackendPID() to return negative values due to it
filling be_pid with random bytes (even these days pid_max can only be
set up to 2^22 on 64b machines on Linux, for example, so this cannot
happen with normal PID numbers).  When this happens, pg_basebackup may
generate a temporary slot name that may not be accepted by the parser,
leading to spurious failures, like:
pg_basebackup: error: could not send replication command
ERROR:  replication slot name "pg_basebackup_-1201966863" contains
invalid character

This commit fixes that problem by formatting the result from
PQbackendPID() as an unsigned integer when creating the temporary
replication slot name, so as the invalid character is gone and the
command can be parsed.

Author: Jelte Fennema
Reviewed-by: Daniel Gustafsson, Nishant Sharma
Discussion: https://postgr.es/m/CAGECzQQOGvYfp8ziF4fWQ_o8s2K7ppaoWBQnTmdakn3s-4Z=5g@mail.gmail.com
Backpatch-through: 11
2023-09-07 14:12:36 +09:00
Bruce Momjian 69e22dd38f doc: mention that to_char() values are rounded
Reported-by: barsikdacat@gmail.com

Diagnosed-by: Laurenz Albe

Discussion: https://postgr.es/m/168991536429.626.9957835774751337210@wrigleys.postgresql.org

Author: Laurenz Albe

Backpatch-through: 11
2023-09-06 16:52:24 -04:00
Bruce Momjian 7a7526ab54 doc: mention libpq regression tests
Reported-by: Ryo Matsumura

Discussion: https://postgr.es/m/TYCPR01MB11316B3FB56EE54D70BF0CEF6E8E4A@TYCPR01MB11316.jpnprd01.prod.outlook.com

Backpatch-through: 11
2023-09-05 13:05:27 -04:00
Michael Paquier 358cd2b251 Fix out-of-bound read in gtsvector_picksplit()
This could lead to an imprecise choice when splitting an index page of a
GiST index on a tsvector, deciding which entries should remain on the
old page and which entries should move to a new page.

This is wrong since tsearch2 has been moved into core with commit
140d4ebcb4, so backpatch all the way down.  This error has been
spotted by valgrind.

Author: Alexander Lakhin
Discussion: https://postgr.es/m/17950-6c80a8d2b94ec695@postgresql.org
Backpatch-through: 11
2023-09-04 14:55:58 +09:00
Etsuro Fujita eafe9c9181 postgres_fdw: Fix test for parameterized foreign scan.
Commit e4106b252 should have updated this test, but did not; back-patch
to all supported branches.

Reviewed by Richard Guo.

Discussion: http://postgr.es/m/CAPmGK15nR0NXLSCKQAcqbZbTzrzd5MozowWnTnGfPkayndF43Q%40mail.gmail.com
2023-08-30 17:15:10 +09:00
Andrew Dunstan dd9779141e Silence compiler warning in release 11 and 12 branches
The offending code is not present in later branches.

Discussion: https://postgr.es/m/ba2150c1-8485-6597-fafe-4fcd39e49c28@dunslane.net
2023-08-27 07:03:53 -04:00
Andrew Dunstan b915bf495f Include header file inadvertently missed in commit 2d13dab048
per gripe from Tom Lane.
2023-08-24 16:14:26 -04:00
Tom Lane 9c59f3862b Avoid unnecessary plancache revalidation of utility statements.
Revalidation of a plancache entry (after a cache invalidation event)
requires acquiring a snapshot.  Normally that is harmless, but not
if the cached statement is one that needs to run without acquiring a
snapshot.  We were already aware of that for TransactionStmts,
but for some reason hadn't extrapolated to the other statements that
PlannedStmtRequiresSnapshot() knows mustn't set a snapshot.  This can
lead to unexpected failures of commands such as SET TRANSACTION
ISOLATION LEVEL.  We can fix it in the same way, by excluding those
command types from revalidation.

However, we can do even better than that: there is no need to
revalidate for any statement type for which parse analysis, rewrite,
and plan steps do nothing interesting, which is nearly all utility
commands.  To mechanize this, invent a parser function
stmt_requires_parse_analysis() that tells whether parse analysis does
anything beyond wrapping a CMD_UTILITY Query around the raw parse
tree.  If that's what it does, then rewrite and plan will just
skip the Query, so that it is not possible for the same raw parse
tree to produce a different plan tree after cache invalidation.

stmt_requires_parse_analysis() is basically equivalent to the
existing function analyze_requires_snapshot(), except that for
obscure reasons that function omits ReturnStmt and CallStmt.
It is unclear whether those were oversights or intentional.
I have not been able to demonstrate a bug from not acquiring a
snapshot while analyzing these commands, but at best it seems mighty
fragile.  It seems safer to acquire a snapshot for parse analysis of
these commands too, which allows making stmt_requires_parse_analysis
and analyze_requires_snapshot equivalent.

In passing this fixes a second bug, which is that ResetPlanCache
would exclude ReturnStmts and CallStmts from revalidation.
That's surely *not* safe, since they contain parsable expressions.

Per bug #18059 from Pavel Kulakov.  Back-patch to all supported
branches.

Discussion: https://postgr.es/m/18059-79c692f036b25346@postgresql.org
2023-08-24 12:02:40 -04:00
Andrew Dunstan 2d13dab048 Cache by-reference missing values in a long lived context
Attribute missing values might be needed past the lifetime of the tuple
descriptors from which they are extracted. To avoid possibly using
pointers for by-reference values which might thus be left dangling, we
cache a datumCopy'd version of the datum in the TopMemoryContext. Since
we first search for the value this only needs to be done once per
session for any such value.

Original complaint from Tom Lane, idea for mitigation by Andrew Dunstan,
tweaked by Tom Lane.

Backpatch to version 11 where missing values were introduced.

Discussion: https://postgr.es/m/1306569.1687978174@sss.pgh.pa.us
2023-08-23 17:22:16 -04:00
Daniel Gustafsson c176d97895 doc: Replace list of drivers and PLs with wiki link
The list of external language drivers and procedural languages was
never complete or exhaustive, and rather than attempting to manage
it the content has migrated to the wiki.  This replaces the tables
altogether with links to the wiki as we regularly get requests for
adding various projects,  which we reject without any clear policy
for why or how the content should be managed.

The threads linked to below are the most recent discussions about
this, the archives contain many more.

Backpatch to all supported branches since the list on the wiki
applies to all branches.

Author: Jonathan Katz <jkatz@postgresql.org>
Discussion: https://postgr.es/m/169165415312.635.10247434927885764880@wrigleys.postgresql.org
Discussion: https://postgr.es/m/169177958824.635.11087800083040275266@wrigleys.postgresql.org
Backpatch-through: v11
2023-08-23 14:13:07 +02:00
Jeff Davis ae12692950 Remove test from commit fa2e874946.
The fix itself is fine, but the test revealed other problems related
to parallel query that are not easily fixable. Remove the test for
now to fix the buildfarm.

Discussion: https://postgr.es/m/88825.1691665432@sss.pgh.pa.us
Backpatch-through: 11
2023-08-10 10:27:24 -07:00
Jeff Davis 43ba5105a8 Recalculate search_path after ALTER ROLE.
Renaming a role can affect the meaning of the special string $user, so
must cause search_path to be recalculated.

Discussion: https://postgr.es/m/186761d32c0255debbdf50b6310b581b9c973e6c.camel@j-davis.com
Reviewed-by: Nathan Bossart, Michael Paquier
Backpatch-through: 11
2023-08-07 15:09:11 -07:00
Tom Lane a2cbee74b0 Stamp 11.21. 2023-08-07 16:15:30 -04:00
Tom Lane 023fa8f326 Last-minute updates for release notes.
Security: CVE-2023-39417, CVE-2023-39418
2023-08-07 12:50:15 -04:00
Noah Misch 919ebb023e Reject substituting extension schemas or owners matching ["$'\].
Substituting such values in extension scripts facilitated SQL injection
when @extowner@, @extschema@, or @extschema:...@ appeared inside a
quoting construct (dollar quoting, '', or "").  No bundled extension was
vulnerable.  Vulnerable uses do appear in a documentation example and in
non-bundled extensions.  Hence, the attack prerequisite was an
administrator having installed files of a vulnerable, trusted,
non-bundled extension.  Subject to that prerequisite, this enabled an
attacker having database-level CREATE privilege to execute arbitrary
code as the bootstrap superuser.  By blocking this attack in the core
server, there's no need to modify individual extensions.  Back-patch to
v11 (all supported versions).

Reported by Micah Gate, Valerie Woolard, Tim Carey-Smith, and Christoph
Berg.

Security: CVE-2023-39417
2023-08-07 06:06:01 -07:00
Peter Eisentraut 94abb95e3c Translation updates
Source-Git-URL: https://git.postgresql.org/git/pgtranslation/messages.git
Source-Git-Hash: f6a99caeb18f1106ee1c619801b6eb5f3fef10a4
2023-08-07 12:38:17 +02:00
Tom Lane 1e392aa5a3 Release notes for 15.4, 14.9, 13.12, 12.16, 11.21. 2023-08-05 16:47:05 -04:00
Etsuro Fujita 0a1ff1d724 Doc: update documentation for creating custom scan paths.
Commit f49842d1e added a new callback for custom scan paths, but missed
updating the documentation.

Back-patch to all supported branches.

Discussion: https://postgr.es/m/CAPmGK15ODkN%2B%3DhkBCufj1HBW0x5OTb65Xuy7ryXchMdiCMpx_g%40mail.gmail.com
2023-08-03 17:45:09 +09:00
Etsuro Fujita db395e2239 Update comments on CustomPath struct.
Commit e7cb7ee14 allowed custom scan providers to create CustomPath
paths for join relations as well, but missed updating the comments.

Back-patch to all supported branches.

Discussion: https://postgr.es/m/CAPmGK15ODkN%2B%3DhkBCufj1HBW0x5OTb65Xuy7ryXchMdiCMpx_g%40mail.gmail.com
2023-08-03 17:15:09 +09:00
Etsuro Fujita db01f26968 Disallow replacing joins with scans in problematic cases.
Commit e7cb7ee14, which introduced the infrastructure for FDWs and
custom scan providers to replace joins with scans, failed to add support
handling of pseudoconstant quals assigned to replaced joins in
createplan.c, leading to an incorrect plan without a gating Result node
when postgres_fdw replaced a join with such a qual.

To fix, we could add the support by 1) modifying the ForeignPath and
CustomPath structs to store the list of RestrictInfo nodes to apply to
the join, as in JoinPaths, if they represent foreign and custom scans
replacing a join with a scan, and by 2) modifying create_scan_plan() in
createplan.c to use that list in that case, instead of the
baserestrictinfo list, to get pseudoconstant quals assigned to the join;
but #1 would cause an ABI break.  So fix by modifying the infrastructure
to just disallow replacing joins with such quals.

Back-patch to all supported branches.

Reported by Nishant Sharma.  Patch by me, reviewed by Nishant Sharma and
Richard Guo.

Discussion: https://postgr.es/m/CADrsxdbcN1vejBaf8a%2BQhrZY5PXL-04mCd4GDu6qm6FigDZd6Q%40mail.gmail.com
2023-07-28 15:45:09 +09:00
Tom Lane 1d031ad54d Raise fixed token-length limit in hba.c.
Historically, hba.c limited tokens in the authentication configuration
files (pg_hba.conf and pg_ident.conf) to less than 256 bytes.  We have
seen a few reports of this limit causing problems; notably, for
moderately-complex LDAP configurations.  Increase the limit to 10240
bytes as a low-risk stop-gap solution.

In v13 and earlier, this also requires raising MAX_LINE, the limit
on overall line length.  I'm hesitant to make this code consume
too much stack space, so I only raised that to 20480 bytes.

Discussion: https://postgr.es/m/1588937.1690221208@sss.pgh.pa.us
2023-07-27 12:07:48 -04:00
Tom Lane fd7c944690 Doc: improve description of IN and row-constructor comparisons.
IN and NOT IN work fine on records and arrays, so just say that
they accept "expressions" not "scalar expressions".  I think that
that phrasing was meant to say that they don't work on set-returning
expressions, but that's not the common meaning of "scalar".

Revise the description of row-constructor comparisons to make it
perhaps a bit less confusing.  (This partially reverts some
dubious wording changes made by commit f56651519.)

Per gripe from Ilya Nenashev.  Back-patch to supported branches.
In HEAD and v16, also drop a NOTE about pre-8.2 behavior, which
is hopefully no longer of interest to anybody.

Discussion: https://postgr.es/m/168968062460.632.14303906825812821399@wrigleys.postgresql.org
2023-07-19 11:00:34 -04:00
Tom Lane df73e8bad6 Doc: fix out-of-date example of SPI usage.
The "count" argument of SPI_exec() only limits execution when
the query is actually returning rows.  This was not the case
before PG 9.0, so this example was correct when written; but
we missed updating it in commit 2ddc600f8.  Extend the example
to show the behavior both with and without RETURNING.

While here, improve the commentary and markup for the rest
of the example.

David G. Johnston and Tom Lane, per report from Curt Kolovson.
Back-patch to all supported branches.

Discussion: https://postgr.es/m/CANhYJV6HWtgz_qjx_APfK0PAgLUzY-2vjLuj7i_o=TZF1LAQew@mail.gmail.com
2023-07-18 11:59:39 -04:00
Michael Paquier 6c7bffc096 Fix indentation in twophase.c
This has been missed in cb0cca1, noticed before buildfarm member koel
has been able to complain while poking at a different patch.  Like the
other commit, backpatch all the way down to limit the odds of merge
conflicts.

Backpatch-through: 11
2023-07-18 14:04:54 +09:00
Michael Paquier bc0581f8fb Fix recovery of 2PC transaction during crash recovery
A crash in the middle of a checkpoint with some two-phase state data
already flushed to disk by this checkpoint could cause a follow-up crash
recovery to recover twice the same transaction, once from what has been
found in pg_twophase/ at the beginning of recovery and a second time
when replaying its corresponding record.

This would lead to FATAL failures in the startup process during
recovery, where the same transaction would have a state recovered twice
instead of once:
LOG:  recovering prepared transaction 731 from shared memory
LOG:  recovering prepared transaction 731 from shared memory
FATAL:  lock ExclusiveLock on object 731/0/0 is already held

This issue is fixed by skipping the addition of any 2PC state coming
from a record whose equivalent 2PC state file has already been loaded in
TwoPhaseState at the beginning of recovery by restoreTwoPhaseData(),
which is OK as long as the system has not reached a consistent state.

The timing to get a messed up recovery processing is very racy, and
would very unlikely happen.  The thread that has reported the issue has
demonstrated the bug using injection points to force a PANIC in the
middle of a checkpoint.

Issue introduced in 728bd99, so backpatch all the way down.

Reported-by: "suyu.cmj" <mengjuan.cmj@alibaba-inc.com>
Author: "suyu.cmj" <mengjuan.cmj@alibaba-inc.com>
Author: Michael Paquier
Discussion: https://postgr.es/m/109e6994-b971-48cb-84f6-829646f18b4c.mengjuan.cmj@alibaba-inc.com
Backpatch-through: 11
2023-07-18 13:44:35 +09:00
Michael Paquier db9813819f Add indisreplident to fields refreshed by RelationReloadIndexInfo()
RelationReloadIndexInfo() is a fast-path used for index reloads in the
relation cache, and it has always forgotten about updating
indisreplident, which is something that would happen after an index is
selected for a replica identity.  This can lead to incorrect cache
information provided when executing a command in a transaction context
that updates indisreplident.

None of the code paths currently on HEAD that need to check upon
pg_index.indisreplident fetch its value from the relation cache, always
relying on a fresh copy on the syscache.  Unfortunately, this may not be
the case of out-of-core code, that could see out-of-date value.

Author: Shruthi Gowda
Reviewed-by: Robert Haas, Dilip Kumar, Michael Paquier
Discussion: https://postgr.es/m/CAASxf_PBcxax0wW-3gErUyftZ0XrCs3Lrpuhq4-Z3Fak1DoW7Q@mail.gmail.com
Backpatch-through: 11
2023-07-14 11:16:13 +09:00
Michael Paquier ed2b58c153 Fix updates of indisvalid for partitioned indexes
indisvalid is switched to true for partitioned indexes when all its
partitions have valid indexes when attaching a new partition, up to the
top-most parent if all its leaves are themselves valid when dealing with
multiple layers of partitions.

The copy of the tuple from pg_index used to switch indisvalid to true
came from the relation cache, which is incorrect.  Particularly, in the
case reported by Shruthi Gowda, executing a series of commands in a
single transaction would cause the validation of partitioned indexes to
use an incorrect version of a pg_index tuple, as indexes are reloaded
after an invalidation request with RelationReloadIndexInfo(), a much
faster version than a full index cache rebuild.  In this case, the
limited information updated in the cache leads to an incorrect version
of the tuple used.  One of the symptoms reported was the following
error, with a replica identity update, for instance:
"ERROR: attempted to update invisible tuple"

This is incorrect since 8b08f7d, so backpatch all the way down.

Reported-by: Shruthi Gowda
Author: Michael Paquier
Reviewed-by: Shruthi Gowda, Dilip Kumar
Discussion: https://postgr.es/m/CAASxf_PBcxax0wW-3gErUyftZ0XrCs3Lrpuhq4-Z3Fak1DoW7Q@mail.gmail.com
Backpatch-through: 11
2023-07-14 10:13:22 +09:00
Andres Freund 1c38e7ae17 Handle DROP DATABASE getting interrupted
Until now, when DROP DATABASE got interrupted in the wrong moment, the removal
of the pg_database row would also roll back, even though some irreversible
steps have already been taken. E.g. DropDatabaseBuffers() might have thrown
out dirty buffers, or files could have been unlinked. But we continued to
allow connections to such a corrupted database.

To fix this, mark databases invalid with an in-place update, just before
starting to perform irreversible steps. As we can't add a new column in the
back branches, we use pg_database.datconnlimit = -2 for this purpose.

An invalid database cannot be connected to anymore, but can still be
dropped.

Unfortunately we can't easily add output to psql's \l to indicate that some
database is invalid, it doesn't fit in any of the existing columns.

Add tests verifying that a interrupted DROP DATABASE is handled correctly in
the backend and in various tools.

Reported-by: Evgeny Morozov <postgresql3@realityexists.net>
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/20230509004637.cgvmfwrbht7xm7p6@awork3.anarazel.de
Discussion: https://postgr.es/m/20230314174521.74jl6ffqsee5mtug@awork3.anarazel.de
Backpatch: 11-, bug present in all supported versions
2023-07-13 13:03:37 -07:00
Andres Freund 1386f09871 Release lock after encountering bogs row in vac_truncate_clog()
When vac_truncate_clog() encounters bogus datfrozenxid / datminmxid values, it
returns early. Unfortunately, until now, it did not release
WrapLimitsVacuumLock. If the backend later tries to acquire
WrapLimitsVacuumLock, the session / autovacuum worker hangs in an
uncancellable way. Similarly, other sessions will hang waiting for the
lock. However, if the backend holding the lock exited or errored out for some
reason, the lock was released.

The bug was introduced as a side effect of 566372b3d6.

It is interesting that there are no production reports of this problem. That
is likely due to a mix of bugs leading to bogus values having gotten less
common, process exit releasing locks and instances of hangs being hard to
debug for "normal" users.

Discussion: https://postgr.es/m/20230621221208.vhsqgduwfpzwxnpg@awork3.anarazel.de
2023-07-13 13:03:37 -07:00
Tom Lane 9f70f6d4c5 Remove unnecessary pfree() in g_intbig_compress().
GiST compress functions (like all GiST opclass functions) are
supposed to be called in short-lived memory contexts, so that
minor memory leaks in them are not of concern, and indeed
explicit pfree's are likely slightly counterproductive.
But this one in g_intbig_compress() is more than
slightly counterproductive, because it's guarded by
"if (in != DatumGetArrayTypeP(entry->key))" which means
that if this test succeeds, we've detoasted the datum twice.
(And to add insult to injury, the extra detoast result is
leaked.)  Let's just drop the whole stanza, relying on the
GiST temporary context mechanism to clean up in good time.

The analogous bit in g_int_compress() is
       if (r != (ArrayType *) DatumGetPointer(entry->key))
           pfree(r);
which doesn't have the gratuitous-detoast problem so
I left it alone.  Perhaps there is a case for removing
unnecessary pfree's more widely, but I'm not sure if it's
worth the code churn.

The potential extra decompress seems expensive enough to
justify calling this a (minor) performance bug and
back-patching.

Konstantin Knizhnik, Matthias van de Meent, Tom Lane

Discussion: https://postgr.es/m/CAEze2Wi86=DxErfvf+SCB2UKmU2amKOF60BKuJOX=w-RojRn0A@mail.gmail.com
2023-07-13 13:08:40 -04:00
Tom Lane 671bf1cf27 Be more rigorous about local variables in PostgresMain().
Since PostgresMain calls sigsetjmp, any local variables that are not
marked "volatile" have a risk of unspecified behavior.  In practice
this means that when control returns via longjmp, such variables might
get reset to their values as of the time of sigsetjmp, depending on
whether the compiler chose to put them in registers or on the stack.
We were careful about this for "send_ready_for_query", but not the
other local variables.

In the case of the timeout_enabled flags, resetting them to
their initial "false" states is actually good, since we do
"disable_all_timeouts()" in the longjmp cleanup code path.  If that
does not happen, we risk uselessly calling "disable_timeout()" later,
which is harmless but a little bit expensive.  Let's explicitly reset
these flags so that the behavior is correct and platform-independent.
(This change means that we really don't need the new "volatile"
markings after all, but let's install them anyway since any change
in this logic could re-introduce a problem.)

There is no issue for "firstchar" and "input_message" because those
are explicitly reinitialized each time through the query processing
loop.  To make that clearer, move them to be declared inside the loop.
That leaves us with all the function-lifespan locals except the
sigjmp_buf itself marked as volatile, which seems like a good policy
to have going forward.

Because of the possibility of extra disable_timeout() calls, this
seems worth back-patching.

Sergey Shinderuk and Tom Lane

Discussion: https://postgr.es/m/2eda015b-7dff-47fd-d5e2-f1a9899b90a6@postgrespro.ru
2023-07-10 12:14:34 -04:00
Michael Paquier 914e72e6e8 Fix ALTER EXTENSION SET SCHEMA with objects outside an extension's schema
As coded, the code would use as a base comparison the namespace OID from
the first object scanned in pg_depend when switching its namespace
dependency entry to the new one, and use it as a base of comparison for
any follow-up checks.  It would also be used as the old namespace OID to
switch *from* for the extension's pg_depend entry.  Hence, if the first
object scanned has a namespace different than the one stored in the
extension, we would finish by:
- Not checking that the extension objects map with the extension's
schema.
- Not switching the extension -> namespace dependency entry to the new
namespace provided by the user, making ALTER EXTENSION ineffective.

This issue exists since this command has been introduced in d9572c4 for
relocatable extension, so backpatch all the way down to 11.  The test
case has been provided by Heikki, that I have tweaked a bit to show the
effects on pg_depend for the extension.

Reported-by: Heikki Linnakangas
Author: Michael Paquier, Heikki Linnakangas
Discussion: https://postgr.es/m/20eea594-a05b-4c31-491b-007b6fceef28@iki.fi
Backpatch-through: 11
2023-07-10 09:40:24 +09:00
Andres Freund 6143602eba Fix type of iterator variable in SH_START_ITERATE
Also add comment to make the reasoning behind the Assert() more explicit (per
Tom).

Reported-by: Ranier Vilela
Discussion: https://postgr.es/m/CAEudQAocXNJ6s1VLz+hMamLAQAiewRoW17OJ6-+9GACKfj6iPQ@mail.gmail.com
Backpatch: 11-
2023-07-06 09:57:33 -07:00
Andrew Dunstan 2e99ce68bc Skip pg_baseback long filename test if path too long on Windows
On Windows, it's sometimes difficult to create a file with a path longer
than 255 chars, and if it can be created it might not be seen by the
archiver. This can be triggered by the test for tar backups with
filenames greater than 100 bytes. So we skip that test if the path would
exceed 255.

Backpatch to all live branches.

Reviewed by Daniel Gustafsson

Discussion: https://postgr.es/m/666ac55b-3400-fb2c-2cea-0281bf36a53c@dunslane.net
2023-07-06 12:34:54 -04:00
Heikki Linnakangas 988719b88d WAL-log the creation of the init fork of unlogged indexes.
We create a file, so we better WAL-log it. In practice, all the
built-in index AMs and all extensions that I'm aware of write a
metapage to the init fork, which is WAL-logged, and replay of the
metapage implicitly creates the fork too. But if ambuildempty() didn't
write any page, we would miss it.

This can be seen with dummy_index_am. Set up replication, create a
'dummy_index_am' index on an unlogged table, and look at the files
created in the replica: the init fork is not created on the
replica. Dummy_index_am doesn't do anything with the relation files,
however, so it doesn't lead to any user-visible errors.

Backpatch to all supported versions.

Reviewed-by: Robert Haas
Discussion: https://www.postgresql.org/message-id/6e5bbc08-cdfc-b2b3-9e23-1a914b9850a9%40iki.fi
2023-07-06 17:29:16 +03:00
Heikki Linnakangas 2316ff1ae5 Fix leak of LLVM "fatal-on-oom" section counter.
llvm_release_context() called llvm_enter_fatal_on_oom(), but was missing
the corresponding llvm_leave_fatal_on_oom() call. As a result, if JIT was
used at all, we were almost always in the "fatal-on-oom" state.

It only makes a difference if you use an extension written in C++, and
run out of memory in a C++ 'new' call. In that case, you would get a
PostgreSQL FATAL error, instead of the default behavior of throwing a
C++ exception.

Back-patch to all supported versions.

Reviewed-by: Daniel Gustafsson
Discussion: https://www.postgresql.org/message-id/54b78cca-bc84-dad8-4a7e-5b56f764fab5@iki.fi
2023-07-05 13:14:33 +03:00
Heikki Linnakangas 6377f705ca Ensure that creation of an empty relfile is fsync'd at checkpoint.
If you create a table and don't insert any data into it, the relation file
is never fsync'd. You don't lose data, because an empty table doesn't have
any data to begin with, but if you crash and lose the file, subsequent
operations on the table will fail with "could not open file" error.

To fix, register an fsync request in mdcreate(), like we do for mdwrite().

Per discussion, we probably should also fsync the containing directory
after creating a new file. But that's a separate and much wider issue.

Backpatch to all supported versions.

Reviewed-by: Andres Freund, Thomas Munro
Discussion: https://www.postgresql.org/message-id/d47d8122-415e-425c-d0a2-e0160829702d%40iki.fi
2023-07-04 18:08:40 +03:00
Peter Eisentraut c2cff443b0 Adjust kerberos and ldap tests for Homebrew on ARM
The Homebrew package manager changed its default installation prefix
for the new architecture, so a couple of tests need tweaks to find
binaries.

This is a partial backpatch of dc513bc654.
2023-07-04 11:30:40 +02:00
Thomas Munro 1605623ec6 Re-bin segment when memory pages are freed.
It's OK to be lazy about re-binning memory segments when allocating,
because that can only leave segments in a bin that's too high.  We'll
search higher bins if necessary while allocating next time, and
also eventually re-bin, so no memory can become unreachable that way.

However, when freeing memory, the largest contiguous range of free pages
might go up, so we should re-bin eagerly to make sure we don't leave the
segment in a bin that is too low for get_best_segment() to find.

The re-binning code is moved into a function of its own, so it can be
called whenever free pages are returned to the segment's free page map.

Back-patch to all supported releases.

Author: Dongming Liu <ldming101@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier version)
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CAL1p7e8LzB2LSeAXo2pXCW4%2BRya9s0sJ3G_ReKOU%3DAjSUWjHWQ%40mail.gmail.com
2023-07-04 16:13:12 +12:00
Thomas Munro 13f127800f Fix race in SSI interaction with gin fast path.
The ginfast.c code previously checked for conflicts in before locking
the relevant buffer, leaving a window where a RW conflict could be
missed.  Re-order.

There was also a place where buffer ID and block number were confused
while trying to predicate-lock a page, noted by visual inspection.

Back-patch to all supported releases.  Fixes one more problem discovered
with the reproducer from bug #17949, in this case when Dmitry tried
other index types.

Reported-by: Artem Anisimov <artem.anisimov.255@gmail.com>
Reported-by: Dmitry Dolgov <9erthalion6@gmail.com>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/17949-a0f17035294a55e2%40postgresql.org
2023-07-04 09:40:30 +12:00