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2025-01-02Ignore nullingrels when looking up statisticsRichard Guo
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
2024-12-28Exclude parallel workers from connection privilege/limit checks.Tom Lane
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
2024-12-28Reserve a PGPROC slot and semaphore for the slotsync worker process.Tom Lane
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
2024-12-21Update TransactionXmin when MyProc->xmin is updatedHeikki Linnakangas
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
2024-12-09Improve comment about dropped entries in pgstat.cMichael Paquier
pgstat_write_statsfile() discards any entries marked as dropped from being written to the stats file at shutdown, and also included an assertion based on the same condition. The intention of the assertion is to track that no pgstats entries should be left around as terminating backends should drop any entries they still hold references on before the stats file is written by the checkpointer, and it not worth taking down the server in this case if there is a bug making that possible. Let's improve the comment of this area to document clearly what's intended. Based on a discussion with Bertrand Drouvot and Anton A. Melnikov. Author: Bertrand Drouvot Discussion: https://postgr.es/m/a13e8cdf-b97a-4ecb-8f42-aaa367974e29@postgrespro.ru Backpatch-through: 15
2024-12-09Fix invalidation of local pgstats references for entry reinitializationMichael Paquier
818119afccd3 has introduced the "generation" concept in pgstats entries, incremented a counter when a pgstats entry is reinitialized, but it did not count on the fact that backends still holding local references to such entries need to be refreshed if the cache age is outdated. The previous logic only updated local references when an entry was dropped, but it needs also to consider entries that are reinitialized. This matters for replication slot stats (as well as custom pgstats kinds in 18~), where concurrent drops and creates of a slot could cause incorrect stats to be locally referenced. This would lead to an assertion failure at shutdown when writing out the stats file, as the backend holding an outdated local reference would not be able to drop during its shutdown sequence the stats entry that should be dropped, as the last process holding a reference to the stats entry. The checkpointer was then complaining about such an entry late in the shutdown sequence, after the shutdown checkpoint is finished with the control file updated, causing the stats file to not be generated. In non-assert builds, the entry would just be skipped with the stats file written. Note that only logical replication slots use statistics. A test case based on TAP is added to test_decoding, where a persistent connection peeking at a slot's data is kept with concurrent drops and creates of the same slot. This is based on the isolation test case that Anton has sent. As it requires a node shutdown with a check to make sure that the stats file is written with this specific sequence of events, TAP is used instead. Reported-by: Anton A. Melnikov Reviewed-by: Bertrand Drouvot Discussion: https://postgr.es/m/56bf8ff9-dd8c-47b2-872a-748ede82af99@postgrespro.ru Backpatch-through: 15
2024-12-07Fix is_digit labeling of to_timestamp's FFn format codes.Tom Lane
These format codes produce or consume strings of digits, so they should be labeled with is_digit = true, but they were not. This has effect in only one place, where is_next_separator() is checked to see if the preceding format code should slurp up all the available digits. Thus, with a format such as '...SSFF3' with remaining input '12345', the 'SS' code would consume all five digits (and then complain about seconds being out of range) when it should eat only two digits. Per report from Nick Davies. This bug goes back to d589f9446 where the FFn codes were introduced, so back-patch to v13. Discussion: https://postgr.es/m/AM8PR08MB6356AC979252CFEA78B56678B6312@AM8PR08MB6356.eurprd08.prod.outlook.com
2024-11-27Fix pg_get_constraintdef for NOT NULL constraints on domainsÁlvaro Herrera
We added pg_constraint rows for all not-null constraints, first for tables and later for domains; but while the ones for tables were reverted, the ones for domains were not. However, we did accidentally revert ruleutils.c support for the ones on domains in 6f8bb7c1e961, which breaks running pg_get_constraintdef() on them. Put that back. This is only needed in branch 17, because we've reinstated this code in branch master with commit 14e87ffa5c54. Add some new tests in both branches. I couldn't find anything else that needs de-reverting. Reported-by: Erki Eessaar <erki.eessaar@taltech.ee> Reviewed-by: Magnus Hagander <magnus@hagander.net> Discussion: https://postgr.es/m/AS8PR01MB75110350415AAB8BBABBA1ECFE222@AS8PR01MB7511.eurprd01.prod.exchangelabs.com
2024-11-26Clean up newlines following left parenthesesÁlvaro Herrera
Most came in during the 17 cycle, so backpatch there. Some (particularly reorderbuffer.h) are very old, but backpatching doesn't seem useful. Like commits c9d297751959, c4f113e8fef9.
2024-11-25Avoid "you don't own a lock of type ExclusiveLock" in GRANT TABLESPACE.Noah Misch
This WARNING appeared because SearchSysCacheLocked1() read cc_relisshared before catcache initialization, when the field is false unconditionally. On the basis of reading false there, it constructed a locktag as though pg_tablespace weren't relisshared. Only shared catalogs could be affected, and only GRANT TABLESPACE was affected in practice. SearchSysCacheLocked1() callers use one other shared-relation syscache, DATABASEOID. DATABASEOID is initialized by the end of CheckMyDatabase(), making the problem unreachable for pg_database. Back-patch to v13 (all supported versions). This has no known impact before v16, where ExecGrant_common() first appeared. Earlier branches avoid trouble by having a separate ExecGrant_Tablespace() that doesn't use LOCKTAG_TUPLE. However, leaving this unfixed in v15 could ensnare a future back-patch of a SearchSysCacheLocked1() call. Reported by Aya Iwata. Discussion: https://postgr.es/m/OS7PR01MB11964507B5548245A7EE54E70EA212@OS7PR01MB11964.jpnprd01.prod.outlook.com
2024-11-20Avoid assertion failure if a setop leaf query contains setops.Tom Lane
Ordinarily transformSetOperationTree will collect all UNION/ INTERSECT/EXCEPT steps into the setOperations tree of the topmost Query, so that leaf queries do not contain any setOperations. However, it cannot thus flatten a subquery that also contains WITH, ORDER BY, FOR UPDATE, or LIMIT. I (tgl) forgot that in commit 07b4c48b6 and wrote an assertion in rule deparsing that a leaf's setOperations would always be empty. If it were nonempty then we would want to parenthesize the subquery to ensure that the output represents the setop nesting correctly (e.g. UNION below INTERSECT had better get parenthesized). So rather than just removing the faulty Assert, let's change it into an additional case to check to decide whether to add parens. We don't expect that the additional case will ever fire, but it's cheap insurance. Man Zeng and Tom Lane Discussion: https://postgr.es/m/tencent_7ABF9B1F23B0C77606FC5FE3@qq.com
2024-11-15Fix per-session activation of ALTER {ROLE|DATABASE} SET role.Noah Misch
After commit 5a2fed911a85ed6d8a015a6bafe3a0d9a69334ae, the catalog state resulting from these commands ceased to affect sessions. Restore the longstanding behavior, which is like beginning the session with a SET ROLE command. If cherry-picking the CVE-2024-10978 fixes, default to including this, too. (This fixes an unintended side effect of fixing CVE-2024-10978.) Back-patch to v12, like that commit. The release team decided to include v12, despite the original intent to halt v12 commits earlier this week. Tom Lane and Noah Misch. Reported by Etienne LAFARGE. Discussion: https://postgr.es/m/CADOZwSb0UsEr4_UTFXC5k7=fyyK8uKXekucd+-uuGjJsGBfxgw@mail.gmail.com
2024-11-15Fix race conditions with drop of reused pgstats entriesMichael Paquier
This fixes a set of race conditions with cumulative statistics where a shared stats entry could be dropped while it should still be valid in the event when it is reused: an entry may refer to a different object but requires the same hash key. This can happen with various stats kinds, like: - Replication slots that compute internally an index number, for different slot names. - Stats kinds that use an OID in the object key, where a wraparound causes the same key to be used if an OID is used for the same object. - As of PostgreSQL 18, custom pgstats kinds could also be an issue, depending on their implementation. This issue is fixed by introducing a counter called "generation" in the shared entries via PgStatShared_HashEntry, initialized at 0 when an entry is created and incremented when the same entry is reused, to avoid concurrent issues on drop because of other backends still holding a reference to it. This "generation" is copied to the local copy that a backend holds when looking at an object, then cross-checked with the shared entry to make sure that the entry is not dropped even if its "refcount" justifies that if it has been reused. This problem could show up when a backend shuts down and needs to discard any entries it still holds, causing statistics to be removed when they should not, or even an assertion failure. Another report involved a failure in a standby after an OID wraparound, where the startup process would FATAL on a "can only drop stats once", stopping recovery abruptly. The buildfarm has been sporadically complaining about the problem, as well, but the window is hard to reach with the in-core tests. Note that the issue can be reproduced easily by adding a sleep before dshash_find() in pgstat_release_entry_ref() to enlarge the problematic window while repeating test_decoding's isolation test oldest_xmin a couple of times, for example, as pointed out by Alexander Lakhin. Reported-by: Alexander Lakhin, Peter Smith Author: Kyotaro Horiguchi, Michael Paquier Reviewed-by: Bertrand Drouvot Discussion: https://postgr.es/m/CAA4eK1KxuMVyAryz_Vk5yq3ejgKYcL6F45Hj9ZnMNBS-g+PuZg@mail.gmail.com Discussion: https://postgr.es/m/17947-b9554521ad963c9c@postgresql.org Backpatch-through: 15
2024-11-13Fix comment in injection_point.cMichael Paquier
InjectionPointEntry->name was described as a hash key, which was fine when introduced in d86d20f0ba79, but it is not now. Oversight in 86db52a5062a, that has changed the way injection points are stored in shared memory from a hash table to an array. Backpatch-through: 17
2024-11-11Parallel workers use AuthenticatedUserId for connection privilege checks.Tom Lane
Commit 5a2fed911 had an unexpected side-effect: the parallel worker launched for the new test case would fail if it couldn't use a superuser-reserved connection slot. The reason that test failed while all our pre-existing ones worked is that the connection privilege tests in InitPostgres had been based on the superuserness of the leader's AuthenticatedUserId, but after the rearrangements of 5a2fed911 we were testing the superuserness of CurrentUserId, which the new test case deliberately made to be a non-superuser. This all seems very accidental and probably not the behavior we really want, but a security patch is no time to be redesigning things. Pending some discussion about desirable semantics, hack it so that InitPostgres continues to pay attention to the superuserness of AuthenticatedUserId when starting a parallel worker. Nathan Bossart and Tom Lane, per buildfarm member sawshark. Security: CVE-2024-10978
2024-11-11Fix improper interactions between session_authorization and role.Tom Lane
The SQL spec mandates that SET SESSION AUTHORIZATION implies SET ROLE NONE. We tried to implement that within the lowest-level functions that manipulate these settings, but that was a bad idea. In particular, guc.c assumes that it doesn't matter in what order it applies GUC variable updates, but that was not the case for these two variables. This problem, compounded by some hackish attempts to work around it, led to some security-grade issues: * Rolling back a transaction that had done SET SESSION AUTHORIZATION would revert to SET ROLE NONE, even if that had not been the previous state, so that the effective user ID might now be different from what it had been. * The same for SET SESSION AUTHORIZATION in a function SET clause. * If a parallel worker inspected current_setting('role'), it saw "none" even when it should see something else. Also, although the parallel worker startup code intended to cope with the current role's pg_authid row having disappeared, its implementation of that was incomplete so it would still fail. Fix by fully separating the miscinit.c functions that assign session_authorization from those that assign role. To implement the spec's requirement, teach set_config_option itself to perform "SET ROLE NONE" when it sets session_authorization. (This is undoubtedly ugly, but the alternatives seem worse. In particular, there's no way to do it within assign_session_authorization without incompatible changes in the API for GUC assign hooks.) Also, improve ParallelWorkerMain to directly set all the relevant user-ID variables instead of relying on some of them to get set indirectly. That allows us to survive not finding the pg_authid row during worker startup. In v16 and earlier, this includes back-patching 9987a7bf3 which fixed a violation of GUC coding rules: SetSessionAuthorization is not an appropriate place to be throwing errors from. Security: CVE-2024-10978
2024-11-06Fix lc_collate_is_c() when LC_COLLATE != LC_CTYPE.Jeff Davis
An unfortunate typo in commit 2d819a08a1 can cause wrong results when the default collation provider is libc, LC_CTYPE=C, and LC_COLLATE is a real locale. Users with this combination of settings must REINDEX all affected indexes. The same typo can also cause performance degradation when LC_COLLATE=C and LC_CTYPE is a real locale. Problem does not exist in master (due to refactoring), so fix only in version 17. Reported-by: Drew Callahan Discussion: https://postgr.es/m/d5081a7f4f6d425c28dd69d1e09b2e78f149e726.camel@j-davis.com
2024-11-05Clear padding of PgStat_HashKey when handling pgstats entriesMichael Paquier
PgStat_HashKey is currently initialized in a way that could result in random data if the structure has any padding bytes. The structure has no padding bytes currently, fortunately, but it could become a problem should the structure change at some point in the future. The code is changed to use some memset(0) so as any padding would be handled properly, as it would be surprising to see random failures in the pgstats entry lookups. PgStat_HashKey is a structure internal to pgstats, and an ABI change could be possible in the scope of a bug fix, so backpatch down to 15 where this has been introduced. Author: Bertrand Drouvot Reviewed-by: Jelte Fennema-Nio, Michael Paquier Discussion: https://postgr.es/m/Zyb7RW1y9dVfO0UH@ip-10-97-1-34.eu-west-3.compute.internal Backpatch-through: 15
2024-11-02Revert "For inplace update, send nontransactional invalidations."Noah Misch
This reverts commit 95c5acb3fc261067ab65ddc0b2dca8e162f09442 (v17) and counterparts in each other non-master branch. If released, that commit would have caused a worst-in-years minor release regression, via undetected LWLock self-deadlock. This commit and its self-deadlock fix warrant more bake time in the master branch. Reported by Alexander Lakhin. Discussion: https://postgr.es/m/10ec0bc3-5933-1189-6bb8-5dec4114558e@gmail.com
2024-10-25For inplace update, send nontransactional invalidations.Noah Misch
The inplace update survives ROLLBACK. The inval didn't, so another backend's DDL could then update the row without incorporating the inplace update. In the test this fixes, a mix of CREATE INDEX and ALTER TABLE resulted in a table with an index, yet relhasindex=f. That is a source of index corruption. Back-patch to v12 (all supported versions). The back branch versions don't change WAL, because those branches just added end-of-recovery SIResetAll(). All branches change the ABI of extern function PrepareToInvalidateCacheTuple(). No PGXN extension calls that, and there's no apparent use case in extensions. Reviewed by Nitin Motiani and (in earlier versions) Andres Freund. Discussion: https://postgr.es/m/20240523000548.58.nmisch@google.com
2024-10-11Fix missed case for builtin collation provider.Jeff Davis
A missed check for the builtin collation provider could result in falling through to call isalpha(). This does not appear to have practical consequences because it only happens for characters in the ASCII range. Regardless, the builtin provider should not be calling libc functions, so backpatch. Discussion: https://postgr.es/m/1bd5a0a5192f82c22ee7527e825b18ab0028b2c7.camel@j-davis.com Backpatch-through: 17
2024-10-09Avoid crash in estimate_array_length with null root pointer.Tom Lane
Commit 9391f7152 added a "PlannerInfo *root" parameter to estimate_array_length, but failed to consider the possibility that NULL would be passed for that, leading to a null pointer dereference. We could rectify the particular case shown in the bug report by fixing simplify_function/inline_function to pass through the root pointer. However, as long as eval_const_expressions is documented to accept NULL for root, similar hazards would remain. For now, let's just do the narrow fix of hardening estimate_array_length to not crash. Its behavior with NULL root will be the same as it was before 9391f7152, so this is not too awful. Per report from Fredrik Widlert (via Paul Ramsey). Back-patch to v17 where 9391f7152 came in. Discussion: https://postgr.es/m/518339E7-173E-45EC-A0FF-9A4A62AA4F40@cleverelephant.ca
2024-10-07Fix Y2038 issues with MyStartTime.Nathan Bossart
Several places treat MyStartTime as a "long", which is only 32 bits wide on some platforms. In reality, MyStartTime is a pg_time_t, i.e., a signed 64-bit integer. This will lead to interesting bugs on the aforementioned systems in 2038 when signed 32-bit integers are no longer sufficient to store Unix time (e.g., "pg_ctl start" hanging). To fix, ensure that MyStartTime is handled as a 64-bit value everywhere. (Of course, users will need to ensure that time_t is 64 bits wide on their system, too.) Co-authored-by: Max Johnson Discussion: https://postgr.es/m/CO1PR07MB905262E8AC270FAAACED66008D682%40CO1PR07MB9052.namprd07.prod.outlook.com Backpatch-through: 12
2024-10-06Ignore not-yet-defined Portals in pg_cursors view.Tom Lane
pg_cursor() supposed that any Portal it finds in the hash table must have sourceText set up, but there's an edge case where that is not so. A newly-created Portal has sourceText = NULL, and that doesn't change until PortalDefineQuery is called. In SPI_cursor_open_internal, we perform GetCachedPlan between CreatePortal and PortalDefineQuery, and it's possible for user-defined code to execute during that planning and cause a fetch from the pg_cursors view, resulting in a null-pointer-dereference crash. (It looks like the same could happen in exec_bind_message, but I've not tried to provoke a failure there.) I considered trying to fix this by setting sourceText sooner, but there may be instances of this same calling pattern in extensions, and we couldn't be sure they'd get the memo promptly. It seems better to redefine pg_cursor as not showing Portals that have not yet had PortalDefineQuery called on them, which we can do by just skipping them if sourceText is still NULL. (Before a1c692358, pg_cursor would instead return a row with NULL in the statement column. We could revert to that behavior but it doesn't really seem like a better definition, especially since our documentation doesn't suggest that the column could be NULL.) Per report from PetSerAl. Back-patch to all supported branches. Discussion: https://postgr.es/m/CAKygsHTBXLXjwV43kpZa+Cs+XTiaeeJiZdL4cPBm9f4MTdw7wg@mail.gmail.com
2024-10-05Reject non-ASCII locale names.Thomas Munro
Commit bf03cfd1 started scanning all available BCP 47 locale names on Windows. This caused an abort/crash in the Windows runtime library if the default locale name contained non-ASCII characters, because of our use of the setlocale() save/restore pattern with "char" strings. After switching to another locale with a different encoding, the saved name could no longer be understood, and setlocale() would abort. "Turkish_Türkiye.1254" is the example from recent reports, but there are other examples of countries and languages with non-ASCII characters in their names, and they appear in Windows' (old style) locale names. To defend against this: 1. In initdb, reject non-ASCII locale names given explicity on the command line, or returned by the operating system environment with setlocale(..., ""), or "canonicalized" by the operating system when we set it. 2. In initdb only, perform the save-and-restore with Windows' non-standard wchar_t variant of setlocale(), so that it is not subject to round trip failures stemming from char string encoding confusion. 3. In the backend, we don't have to worry about the save-and-restore problem because we have already vetted the defaults, so we just have to make sure that CREATE DATABASE also rejects non-ASCII names in any new databases. SET lc_XXX doesn't suffer from the problem, but the ban applies to it too because it uses check_locale(). CREATE COLLATION doesn't suffer from the problem either, but it doesn't use check_locale() so it is not included in the new ban for now, to minimize the change. Anyone who encounters the new error message should either create a new duplicated locale with an ASCII-only name using Windows Locale Builder, or consider using BCP 47 names like "tr-TR". Users already couldn't initialize a cluster with "Turkish_Türkiye.1254" on PostgreSQL 16+, but the new failure mode is an error message that explains why, instead of a crash. Back-patch to 16, where bf03cfd1 landed. Older versions are affected in theory too, but only 16 and later are causing crash reports. Reviewed-by: Andrew Dunstan <andrew@dunslane.net> (the idea, not the patch) Reported-by: Haifang Wang (Centific Technologies Inc) <v-haiwang@microsoft.com> Discussion: https://postgr.es/m/PH8PR21MB3902F334A3174C54058F792CE5182%40PH8PR21MB3902.namprd21.prod.outlook.com
2024-09-24For inplace update durability, make heap_update() callers wait.Noah Misch
The previous commit fixed some ways of losing an inplace update. It remained possible to lose one when a backend working toward a heap_update() copied a tuple into memory just before inplace update of that tuple. In catalogs eligible for inplace update, use LOCKTAG_TUPLE to govern admission to the steps of copying an old tuple, modifying it, and issuing heap_update(). This includes MERGE commands. To avoid changing most of the pg_class DDL, don't require LOCKTAG_TUPLE when holding a relation lock sufficient to exclude inplace updaters. Back-patch to v12 (all supported versions). In v13 and v12, "UPDATE pg_class" or "UPDATE pg_database" can still lose an inplace update. The v14+ UPDATE fix needs commit 86dc90056dfdbd9d1b891718d2e5614e3e432f35, and it wasn't worth reimplementing that fix without such infrastructure. Reviewed by Nitin Motiani and (in earlier versions) Heikki Linnakangas. Discussion: https://postgr.es/m/20231027214946.79.nmisch@google.com
2024-09-15Replace usages of xmlXPathCompile() with xmlXPathCtxtCompile().Tom Lane
In existing releases of libxml2, xmlXPathCompile can be driven to stack overflow because it fails to protect itself against too-deeply-nested input. While there is an upstream fix as of yesterday, it will take years for that to propagate into all shipping versions. In the meantime, we can protect our own usages basically for free by calling xmlXPathCtxtCompile instead. (The actual bug is that libxml2 keeps its nesting counter in the xmlXPathContext, and its parsing code was willing to just skip counting nesting levels if it didn't have a context. So if we supply a context, all is well. It seems odd actually that it works at all to not supply a context, because this means that XPath parsing does not have access to XML namespace info. Apparently libxml2 never checks namespaces until runtime? Anyway, this seems like good future-proofing even if its only immediate effect is to dodge a bug.) Sadly, this hack only offers protection with libxml2 2.9.11 and newer. Before that there are multiple similar problems, so if you are processing untrusted XML it behooves you to get a newer version. But we have some pretty old libxml2 in the buildfarm, so it seems impractical to add a regression test to verify this fix. Per bug #18617 from Jingzhou Fu. Back-patch to all supported versions. Discussion: https://postgr.es/m/18617-1cee4d2ed1f4e7ae@postgresql.org Discussion: https://gitlab.gnome.org/GNOME/libxml2/-/issues/799
2024-09-12Make jsonpath .string() be immutable for datetimes.Tom Lane
Discussion of commit ed055d249 revealed that we don't actually want jsonpath's .string() method to depend on DateStyle, nor TimeZone either, because the non-"_tz" jsonpath functions are supposed to be immutable. Potentially we could allow a TimeZone dependency in the "_tz" variants, but it seems better to just uniformly define this method as returning the same string that jsonb text output would do. That's easier to implement too, saving a couple dozen lines. Patch by me, per complaint from Peter Eisentraut. Back-patch to v17 where this feature came in (in 66ea94e8e). Also back-patch ed055d249 to provide test cases. Discussion: https://postgr.es/m/5e8879d0-a3c8-4be2-950f-d83aa2af953a@eisentraut.org
2024-09-12SQL/JSON: Fix JSON_QUERY(... WITH CONDITIONAL WRAPPER)Amit Langote
Currently, when WITH CONDITIONAL WRAPPER is specified, array wrappers are applied even to a single SQL/JSON item if it is a scalar JSON value, but this behavior does not comply with the standard. To fix, apply wrappers only when there are multiple SQL/JSON items in the result. Reported-by: Peter Eisentraut <peter@eisentraut.org> Author: Peter Eisentraut <peter@eisentraut.org> Author: Amit Langote <amitlangote09@gmail.com> Reviewed-by: Andrew Dunstan <andrew@dunslane.net> Discussion: https://postgr.es/m/8022e067-818b-45d3-8fab-6e0d94d03626%40eisentraut.org Backpatch-through: 17
2024-09-11Fix unique key checks in JSON object constructorsTomas Vondra
When building a JSON object, the code builds a hash table of keys, to allow checking if the keys are unique. The uniqueness check and adding the new key happens in json_unique_check_key(), but this assumes the pointer to the key remains valid. Unfortunately, two places passed pointers to keys in a buffer, while also appending more data (additional key/value pairs) to the buffer. With enough data the buffer is resized by enlargeStringInfo(), which calls repalloc(), invalidating the earlier key pointers. Due to this the uniqueness check may fail with both false negatives and false positives, producing JSON objects with duplicate keys or failing to produce a perfectly valid JSON object. This affects multiple functions that enforce uniqueness of keys, all introduced in PG16 with the new SQL/JSON: - json_object_agg_unique / jsonb_object_agg_unique - json_object / jsonb_objectagg Existing regression tests did not detect the issue, simply because the initial buffer size is 1024 and the objects were small enough not to require the repalloc. With a sufficiently large object, AddressSanitizer reported the access to invalid memory immediately. So would valgrind, of course. Fixed by copying the key into the hash table memory context, and adding regression tests with enough data to repalloc the buffer. Backpatch to 16, where the functions were introduced. Reported by Alexander Lakhin. Investigation and initial fix by Junwang Zhao, with various improvements and tests by me. Reported-by: Alexander Lakhin Author: Junwang Zhao, Tomas Vondra Backpatch-through: 16 Discussion: https://postgr.es/m/18598-3279ed972a2347c7@postgresql.org Discussion: https://postgr.es/m/CAEG8a3JjH0ReJF2_O7-8LuEbO69BxPhYeXs95_x7+H9AMWF1gw@mail.gmail.com
2024-09-10Fix some whitespace issues in XMLSERIALIZE(... INDENT).Tom Lane
We must drop whitespace while parsing the input, else libxml2 will include "blank" nodes that interfere with the desired indentation behavior. The end result is that we didn't indent nodes separated by whitespace. Also, it seems that libxml2 may add a trailing newline when working in DOCUMENT mode. This is semantically insignificant, so strip it. This is in the gray area between being a bug fix and a definition change. However, the INDENT option is still pretty new (since v16), so I think we can get away with changing this in stable branches. Hence, back-patch to v16. Jim Jones Discussion: https://postgr.es/m/872865a8-548b-48e1-bfcd-4e38e672c1e4@uni-muenster.de
2024-09-06Fix incorrect pg_stat_io output on 32-bit machines.Tom Lane
pg_stat_get_io() applied TimestampTzGetDatum twice to the stat_reset_timestamp value. On 64-bit builds that's harmless because TimestampTzGetDatum is a no-op, but on 32-bit builds it results in displaying garbage in the stats_reset column of the pg_stat_io view. Bug dates to commit a9c70b46d which introduced pg_stat_io, so back-patch to v16 where that came in. Bertrand Drouvot Discussion: https://postgr.es/m/Ztrd+XcPTz1zorkg@ip-10-97-1-34.eu-west-3.compute.internal
2024-09-06SQL/JSON: Fix default ON ERROR behavior for JSON_TABLEAmit Langote
Use EMPTY ARRAY instead of EMPTY. This change does not affect the runtime behavior of JSON_TABLE(), which continues to return an empty relation ON ERROR. It only alters whether the default ON ERROR behavior is shown in the deparsed output. Reported-by: Jian He <jian.universality@gmail.com> Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com Backpatch-through: 17
2024-09-06SQL/JSON: Fix JSON_TABLE() column deparsingAmit Langote
The deparsing code in get_json_expr_options() unnecessarily emitted the default column-specific ON ERROR / EMPTY behavior when the top-level ON ERROR behavior in JSON_TABLE was set to ERROR. Fix that by not overriding the column-specific default, determined based on the column's JsonExprOp in get_json_table_columns(), with JSON_BEHAVIOR_ERROR when that is the top-level ON ERROR behavior. Note that this only removes redundancy; the current deparsing output is not incorrect, just redundant. Reviewed-by: Jian He <jian.universality@gmail.com> Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com Backpatch-through: 17
2024-09-06Revert recent SQL/JSON related commitsAmit Langote
Reverts c88ce386c4d, 5067c230b8e, and e4e27976a68, because a few BF animals didn't like one or all of them.
2024-09-06SQL/JSON: Fix default ON ERROR behavior for JSON_TABLEAmit Langote
Use EMPTY ARRAY instead of EMPTY. This change does not affect the runtime behavior of JSON_TABLE(), which continues to return an empty relation ON ERROR. It only alters whether the default ON ERROR behavior is shown in the deparsed output. Reported-by: Jian He <jian.universality@gmail.com> Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com Backpatch-through: 17
2024-09-06SQL/JSON: Fix JSON_TABLE() column deparsingAmit Langote
The deparsing code in get_json_expr_options() unnecessarily emitted the default column-specific ON ERROR / EMPTY behavior when the top-level ON ERROR behavior in JSON_TABLE was set to ERROR. Fix that by not overriding the column-specific default, determined based on the column's JsonExprOp in get_json_table_columns(), with JSON_BEHAVIOR_ERROR when that is the top-level ON ERROR behavior. Note that this only removes redundancy; the current deparsing output is not incorrect, just redundant. Reviewed-by: Jian He <jian.universality@gmail.com> Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com Backpatch-through: 17
2024-08-30Clarify restrict_nonsystem_relation_kind description.Masahiko Sawada
This change improves the description of the restrict_nonsystem_relation_kind parameter in guc_table.c and the documentation for better clarity. Backpatch to 12, where this GUC parameter was introduced. Reviewed-by: Peter Eisentraut Discussion: https://postgr.es/m/6a96f1af-22b4-4a80-8161-1f26606b9ee2%40eisentraut.org Backpatch-through: 12
2024-08-29Fix mis-deparsing of ORDER BY lists when there is a name conflict.Tom Lane
If an ORDER BY item in SELECT is a bare identifier, the parser first seeks it as an output column name of the SELECT (for SQL92 compatibility). However, ruleutils.c is expecting the SQL99 interpretation where such a name is an input column name. So it's possible to produce an incorrect display of a view in the (admittedly pretty ill-advised) case where some other column is renamed in the SELECT output list to match an ORDER BY column. This can be fixed by table-qualifying such names in the dumped view text. To avoid cluttering less-ill-advised queries, we'd like to do so only when there's an actual name conflict. That requires passing the current get_query_def call's resultDesc parameter down to get_variable, so that it can determine what the output column names are. In hopes of reducing rather than increasing notational clutter in ruleutils.c, I moved that value into the deparse_context struct and removed it from the parameter lists of get_query_def's other subroutines. I made a few other cosmetic changes while at it: * Likewise move the colNamesVisible parameter into deparse_context. * Rename deparse_context's windowTList field to targetList, since it's no longer used only in connection with WINDOW clauses. * Replace the special_exprkind field with a bool inGroupBy, since that was all it was being used for, and the apparent flexibility of storing a ParseExprKind proved to be illusory. (We need a separate varInOrderBy field to make this patch work.) * Remove useless save/restore logic in get_select_query_def. In principle, this bug is quite old. However, it seems unreachable before 1b4d280ea, because before that the presence of "new" and "old" entries in a view's rangetable caused us to always table-qualify every Var reference in dumped views. Hence, back-patch to v16 where that came in. Per bug #18589 from Quynh Tran. Discussion: https://postgr.es/m/18589-70091cb81db1a3f1@postgresql.org
2024-08-29Message style improvementsPeter Eisentraut
2024-08-24Revert support for ALTER TABLE ... MERGE/SPLIT PARTITION(S) commandsAlexander Korotkov
This commit reverts 1adf16b8fb, 87c21bb941, and subsequent fixes and improvements including df64c81ca9, c99ef1811a, 9dfcac8e15, 885742b9f8, 842c9b2705, fcf80c5d5f, 96c7381c4c, f4fc7cb54b, 60ae37a8bc, 259c96fa8f, 449cdcd486, 3ca43dbbb6, 2a679ae94e, 3a82c689fd, fbd4321fd5, d53a4286d7, c086896625, 4e5d6c4091, 04158e7fa3. The reason for reverting is security issues related to repeatable name lookups (CVE-2014-0062). Even though 04158e7fa3 solved part of the problem, there are still remaining issues, which aren't feasible to even carefully analyze before the RC deadline. Reported-by: Noah Misch, Robert Haas Discussion: https://postgr.es/m/20240808171351.a9.nmisch%40google.com Backpatch-through: 17
2024-08-22Fix attach of a previously-detached injection point.Noah Misch
It's normal for the name in a free slot to match the new name. The max_inuse mechanism kept simple cases from reaching the problem. The problem could appear when index 0 was the previously-detached entry and index 1 is in use. Back-patch to v17, where this code first appeared.
2024-08-21Don't advance origin during apply failure.Amit Kapila
We advance origin progress during abort on successful streaming and application of ROLLBACK in parallel streaming mode. But the origin shouldn't be advanced during an error or unsuccessful apply due to shutdown. Otherwise, it will result in a transaction loss as such a transaction won't be sent again by the server. Reported-by: Hou Zhijie Author: Hayato Kuroda and Shveta Malik Reviewed-by: Amit Kapila Backpatch-through: 16 Discussion: https://postgr.es/m/TYAPR01MB5692FAC23BE40C69DA8ED4AFF5B92@TYAPR01MB5692.jpnprd01.prod.outlook.com
2024-08-20Fix a couple of wait event descriptions.Nathan Bossart
The descriptions for ProcArrayGroupUpdate and XactGroupUpdate claim that these events mean we are waiting for the group leader "at end of a parallel operation," but neither pertains to parallel operations. This commit reverts these descriptions to their wording before commit 3048898e73, i.e., "end of a parallel operation" is changed to "transaction end." Author: Sameer Kumar Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CAGPeHmh6UMrKQHKCmX%2B5vV5TH9P%3DKw9en3k68qEem6J%3DyrZPUA%40mail.gmail.com Backpatch-through: 13
2024-08-19Fix harmless LC_COLLATE[_MASK] confusion.Thomas Munro
Commit ca051d8b101 called newlocale(LC_COLLATE, ...) instead of newlocale(LC_COLLATE_MASK, ...), in code reached only on FreeBSD. They have the same value on that OS, explaining why it worked. Fix. Back-patch to 14, where ca051d8b101 landed.
2024-08-11Suppress Coverity warnings about Asserts in get_name_for_var_field.Tom Lane
Coverity thinks dpns->plan could be null at these points. That shouldn't really be possible, but it's easy enough to modify the Asserts so they'd not core-dump if it were true. These are new in b919a97a6. Back-patch to v13; the v12 version of the patch didn't have these Asserts.
2024-08-10Allow adjusting session_authorization and role in parallel workers.Tom Lane
The code intends to allow GUCs to be set within parallel workers via function SET clauses, but not otherwise. However, doing so fails for "session_authorization" and "role", because the assign hooks for those attempt to set the subsidiary "is_superuser" GUC, and that call falls foul of the "not otherwise" prohibition. We can't switch to using GUC_ACTION_SAVE for this, so instead add a new GUC variable flag GUC_ALLOW_IN_PARALLEL to mark is_superuser as being safe to set anyway. (This is okay because is_superuser has context PGC_INTERNAL and thus only hard-wired calls can change it. We'd need more thought before applying the flag to other GUCs; but maybe there are other use-cases.) This isn't the prettiest fix perhaps, but other alternatives we thought of would be much more invasive. While here, correct a thinko in commit 059de3ca4: when rejecting a GUC setting within a parallel worker, we should return 0 not -1 if the ereport doesn't longjmp. (This seems to have no consequences right now because no caller cares, but it's inconsistent.) Improve the comments to try to forestall future confusion of the same kind. Despite the lack of field complaints, this seems worth back-patching. Thanks to Nathan Bossart for the idea to invent a new flag, and for review. Discussion: https://postgr.es/m/2833457.1723229039@sss.pgh.pa.us
2024-08-10Lower minimum maintenance_work_mem to 64kBJohn Naylor
Since the introduction of TID store, vacuum uses far less memory in the common case than in versions 16 and earlier. Invoking multiple rounds of index vacuuming in turn requires a much larger table. It'd be a good idea anyway to cover this case in regression testing, and a lower limit is less painful for slow buildfarm animals. The reason to do it now is to re-enable coverage of the bugfix in commit 83c39a1f7f. For consistency, give autovacuum_work_mem the same treatment. Suggested by Andres Freund Tested by Melanie Plageman Backpatch to v17, where TID store was introduced Discussion: https://postgr.es/m/20240516205458.ohvlzis5b5tvejru@awork3.anarazel.de Discussion: https://postgr.es/m/20240722164745.fvaoh6g6zprisqgp%40awork3.anarazel.de
2024-08-09Fix "failed to find plan for subquery/CTE" errors in EXPLAIN.Tom Lane
To deparse a reference to a field of a RECORD-type output of a subquery, EXPLAIN normally digs down into the subquery's plan to try to discover exactly which anonymous RECORD type is meant. However, this can fail if the subquery has been optimized out of the plan altogether on the grounds that no rows could pass the WHERE quals, which has been possible at least since 3fc6e2d7f. There isn't anything remaining in the plan tree that would help us, so fall back to printing the field name as "fN" for the N'th column of the record. (This will actually be the right thing some of the time, since it matches the column names we assign to RowExprs.) In passing, fix a comment typo in create_projection_plan, which I noticed while experimenting with an alternative fix for this. Per bug #18576 from Vasya B. Back-patch to all supported branches. Richard Guo and Tom Lane Discussion: https://postgr.es/m/18576-9feac34e132fea9e@postgresql.org
2024-08-05Restrict accesses to non-system views and foreign tables during pg_dump.Masahiko Sawada
When pg_dump retrieves the list of database objects and performs the data dump, there was possibility that objects are replaced with others of the same name, such as views, and access them. This vulnerability could result in code execution with superuser privileges during the pg_dump process. This issue can arise when dumping data of sequences, foreign tables (only 13 or later), or tables registered with a WHERE clause in the extension configuration table. To address this, pg_dump now utilizes the newly introduced restrict_nonsystem_relation_kind GUC parameter to restrict the accesses to non-system views and foreign tables during the dump process. This new GUC parameter is added to back branches too, but these changes do not require cluster recreation. Back-patch to all supported branches. Reviewed-by: Noah Misch Security: CVE-2024-7348 Backpatch-through: 12