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Author	SHA1	Message	Date
Andrew Dunstan	9577dd523b	Document strange jsonb sort order for empty top level arrays ... Slightly faulty logic in the original jsonb code (commit d9134d0a35) 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	12 months ago
Bruce Momjian	6a2440167a	Update copyright for 2025 ... Backpatch-through: 13	12 months ago
Michael Paquier	58626e24a9	Fix handling of orphaned 2PC files in the future at recovery ... Before 728bd991c3, 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	12 months ago
Tom Lane	c58b0c43d3	Exclude parallel workers from connection privilege/limit checks. ... 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	1 year ago
Noah Misch	536acda0bc	In REASSIGN OWNED of a database, lock the tuple as mandated. ... Commit aac2c9b4fd 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	1 year ago
Michael Paquier	cfd6cbcf9b	Fix memory leak in pgoutput with publication list cache ... 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 f0c569d715 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	1 year ago
Heikki Linnakangas	41eafbb494	Update TransactionXmin when MyProc->xmin is updated ... 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	1 year ago
Thomas Munro	23c743b645	Fix corruption when relation truncation fails. ... 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	1 year ago
Michael Paquier	1f95181b44	Replace durable_rename_excl() by durable_rename(), take two ... durable_rename_excl() attempts to avoid overwriting any existing files by using link() and unlink(), and it falls back to rename() on some platforms (aka WIN32), which offers no such overwrite protection. Most callers use durable_rename_excl() just in case there is an existing file, but in practice there shouldn't be one (see below for more details). Furthermore, failures during durable_rename_excl() can result in multiple hard links to the same file. As per Nathan's tests, it is possible to end up with two links to the same file in pg_wal after a crash just before unlink() during WAL recycling. Specifically, the test produced links to the same file for the current WAL file and the next one because the half-recycled WAL file was re-recycled upon restarting, leading to WAL corruption. This change replaces all the calls of durable_rename_excl() to durable_rename(). This removes the protection against accidentally overwriting an existing file, but some platforms are already living without it and ordinarily there shouldn't be one. The function itself is left around in case any extensions are using it. It will be removed on HEAD via a follow-up commit. Here is a summary of the existing callers of durable_rename_excl() (see second discussion link at the bottom), replaced by this commit. First, basic_archive used it to avoid overwriting an archive concurrently created by another server, but as mentioned above, it will still overwrite files on some platforms. Second, xlog.c uses it to recycle past WAL segments, where an overwrite should not happen (origin of the change at f0e37a8) because there are protections about the WAL segment to select when recycling an entry. The third and last area is related to the write of timeline history files. writeTimeLineHistory() will write a new timeline history file at the end of recovery on promotion, so there should be no such files for the same timeline. What remains is writeTimeLineHistoryFile(), that can be used in parallel by a WAL receiver and the startup process, and some digging of the buildfarm shows that EEXIST from a WAL receiver can happen with an error of "could not link file \"pg_wal/xlogtemp.NN\" to \"pg_wal/MM.history\", which would cause an automatic restart of the WAL receiver as it is promoted to FATAL, hence this should improve the stability of the WAL receiver as rename() would overwrite an existing TLI history file already fetched by the startup process at recovery. This is the second time this change is attempted, ccfbd92 being the first one, but this time no assertions are added for the case of a TLI history file written concurrently by the WAL receiver or the startup process because we can expect one to exist (some of the TAP tests are able to trigger with a proper timing). This commit has been originally applied on v16~ as of dac1ff3090, and we have received more reports of this issue, where clusters can become corrupted at replay in older stable branches with multiple links pointing to the same physical WAL segment file. This backpatch addresses the problem for the v13~v15 range. Author: Nathan Bossart Reviewed-by: Robert Haas, Kyotaro Horiguchi, Michael Paquier Discussion: https://postgr.es/m/20220407182954.GA1231544@nathanxps13 Discussion: https://postgr.es/m/Ym6GZbqQdlalSKSG@paquier.xyz Discussion: https://postgr.es/m/CAJhEC04tBkYPF4q2uS_rCytauvNEVqdBAzasBEokfceFhF=KDQ@mail.gmail.com	1 year ago
David Rowley	bdb07d2411	Fix Assert failure in WITH RECURSIVE UNION queries ... If the non-recursive part of a recursive CTE ended up using TTSOpsBufferHeapTuple as the table slot type, then a duplicate value could cause an Assert failure in CheckOpSlotCompatibility() when checking the hash table for the duplicate value. The expected slot type for the deform step was TTSOpsMinimalTuple so the Assert failed when the TTSOpsBufferHeapTuple slot was used. This is a long-standing bug which we likely didn't notice because it seems much more likely that the non-recursive term would have required projection and used a TTSOpsVirtual slot, which CheckOpSlotCompatibility is ok with. There doesn't seem to be any harm done here other than the Assert failure. Both TTSOpsMinimalTuple and TTSOpsBufferHeapTuple slot types require tuple deformation, so the EEOP_*_FETCHSOME ExprState step would have properly existed in the ExprState. The solution is to pass NULL for the ExecBuildGroupingEqual's 'lops' parameter. This means the ExprState's EEOP_*_FETCHSOME step won't expect a fixed slot type. This makes CheckOpSlotCompatibility() happy as no checking is performed when the ExprEvalStep is not expecting a fixed slot type. Reported-by: Richard Guo Reviewed-by: Tom Lane Discussion: https://postgr.es/m/CAMbWs4-8U9q2LAtf8+ghV11zeUReA3AmrYkxzBEv0vKnDxwkKA@mail.gmail.com Backpatch-through: 13, all supported versions	1 year ago
Nathan Bossart	84dc1303c9	Accommodate very large dshash tables. ... If a dshash table grows very large (e.g., the dshash table for cumulative statistics when there are millions of tables), resizing it may fail with an error like: ERROR: invalid DSA memory alloc request size 1073741824 To fix, permit dshash resizing to allocate more than 1 GB by providing the DSA_ALLOC_HUGE flag. Reported-by: Andreas Scherbaum Author: Matthias van de Meent Reviewed-by: Cédric Villemain, Michael Paquier, Andres Freund Discussion: https://postgr.es/m/80a12d59-0d5e-4c54-866c-e69cd6536471%40pgug.de Backpatch-through: 13	1 year ago
Heikki Linnakangas	f5f5e7b473	Make 009_twophase.pl test pass with recovery_min_apply_delay set ... The test failed if you ran the regression tests with TEMP_CONFIG with recovery_min_apply_delay = '500ms'. Fix the race condition by waiting for transaction to be applied in the replica, like in a few other tests. The failing test was introduced in commit cbfbda7841. Backpatch to all supported versions like that commit (except v12, which is no longer supported). Reported-by: Alexander Lakhin Discussion: https://www.postgresql.org/message-id/09e2a70a-a6c2-4b5c-aeae-040a7449c9f2@gmail.com	1 year ago
Tom Lane	2a23dbcf35	pgbench: fix misprocessing of some nested \if constructs. ... An \if command appearing within a false (not-to-be-executed) \if branch was incorrectly treated the same as \elif. This could allow statements within the inner \if to be executed when they should not be. Also the missing inner \if stack entry would result in an assertion failure (in assert-enabled builds) when the final \endif is reached. Report and patch by Michail Nikolaev. Back-patch to all supported branches. Discussion: https://postgr.es/m/CANtu0oiA1ke=SP6tauhNqkUdv5QFsJtS1p=aOOf_iU+EhyKkjQ@mail.gmail.com	1 year ago
Tom Lane	c7f3c414fd	Fix possible crash in pg_dump with identity sequences. ... If an owned sequence is considered interesting, force its owning table to be marked interesting too. This ensures, in particular, that we'll fetch the owning table's column names so we have the data needed for ALTER TABLE ... ADD GENERATED. Previously there were edge cases where pg_dump could get SIGSEGV due to not having filled in the column names. (The known case is where the owning table has been made part of an extension while its identity sequence is not a member; but there may be others.) Also, if it's an identity sequence, force its dumped-components mask to exactly match the owning table: dump definition only if we're dumping the table's definition, dump data only if we're dumping the table's data, etc. This generalizes the code introduced in commit b965f2617 that set the sequence's dump mask to NONE if the owning table's mask is NONE. That's insufficient to prevent failures, because for example the table's mask might only request dumping ACLs, which would lead us to still emit ALTER TABLE ADD GENERATED even though we didn't create the table. It seems better to treat an identity sequence as though it were an inseparable aspect of the table, matching the treatment used in the backend's dependency logic. Perhaps this policy needs additional refinement, but let's wait to see some field use-cases before changing it further. While here, add a comment in pg_dump.h warning against writing tests like "if (dobj->dump == DUMP_COMPONENT_NONE)", which was a bug in this case. There is one other example in getPublicationNamespaces, which if it's not a bug is at least remarkably unclear and under-documented. Changing that requires a separate discussion, however. Per report from Artur Zakirov. Back-patch to all supported branches. Discussion: https://postgr.es/m/CAKNkYnwXFBf136=u9UqUxFUVagevLQJ=zGd5BsLhCsatDvQsKQ@mail.gmail.com	1 year ago
Álvaro Herrera	4abf615cc8	Backpatch critical performance fixes to pgarch.c ... This backpatches commits beb4e9ba16 and 1fb17b1903 (originally appearing in previously in REL_15_STABLE) to REL_14_STABLE. Performance of the WAL archiver can become pretty critical at times, and reports exist of users getting in serious trouble (hours of downtime, loss of replicas) because of lack of this optimization. We'd like to backpatch these to REL_13_STABLE too, but because of the very invasive changes made by commit d75288fb27 in the 14 timeframe, we deem it too risky :-( Original commit messages appear below. Discussion: https://postgr.es/m/202411131605.m66syq5i5ucl@alvherre.pgsql commit beb4e9ba16 Author: Robert Haas <rhaas@postgresql.org> AuthorDate: Thu Nov 11 15:02:53 2021 -0500 Improve performance of pgarch_readyXlog() with many status files. Presently, the archive_status directory was scanned for each file to archive. When there are many status files, say because archive_command has been failing for a long time, these directory scans can get very slow. With this change, the archiver remembers several files to archive during each directory scan, speeding things up. To ensure timeline history files are archived as quickly as possible, XLogArchiveNotify() forces the archiver to do a new directory scan as soon as the .ready file for one is created. Nathan Bossart, per a long discussion involving many people. It is not clear to me exactly who out of all those people reviewed this particular patch. Discussion: http://postgr.es/m/CA+TgmobhAbs2yabTuTRkJTq_kkC80-+jw=pfpypdOJ7+gAbQbw@mail.gmail.com Discussion: http://postgr.es/m/620F3CE1-0255-4D66-9D87-0EADE866985A@amazon.com commit 1fb17b1903 Author: Tom Lane <tgl@sss.pgh.pa.us> AuthorDate: Wed Dec 29 17:02:50 2021 -0500 Fix issues in pgarch's new directory-scanning logic. The arch_filenames[] array elements were one byte too small, so that a maximum-length filename would get corrupted if another entry were made after it. (Noted by Thomas Munro, fix by Nathan Bossart.) Move these arrays into a palloc'd struct, so that we aren't wasting a few kilobytes of static data in each non-archiver process. Add a binaryheap_reset() call to make it plain that we start the directory scan with an empty heap. I don't think there's any live bug of that sort, but it seems fragile, and this is very cheap insurance. Cleanup for commit beb4e9ba1, so no back-patch needed. Discussion: https://postgr.es/m/CA+hUKGLHAjHuKuwtzsW7uMJF4BVPcQRL-UMZG_HM-g0y7yLkUg@mail.gmail.com	1 year ago
Noah Misch	315264d701	Fix elog(FATAL) before PostmasterMain() or just after fork(). ... Since commit 97550c0711, these failed with "PANIC: proc_exit() called in child process" due to uninitialized or stale MyProcPid. That was reachable if close() failed in ClosePostmasterPorts() or setlocale(category, "C") failed, both unlikely. Back-patch to v13 (all supported versions). Discussion: https://postgr.es/m/20241208034614.45.nmisch@google.com	1 year ago
David Rowley	4922ede979	Doc: fix incorrect EXPLAIN ANALYZE output for bloom indexes ... It looks like the example case was once modified to increase the number of rows but the EXPLAIN ANALYZE output wasn't updated to reflect that. Also adjust the text which discusses the index sizes. With the example table size, the bloom index isn't quite 8 times more space efficient than the btree indexes. Discussion: https://postgr.es/m/CAApHDvovx8kQ0=HTt85gFDAwmTJHpCgiSvRmQZ_6u_g-vQYM_w@mail.gmail.com Backpatch-through: 13, all supported versions	1 year ago
Tom Lane	8a95ad3b20	Simplify executor's determination of whether to use parallelism. ... Our parallel-mode code only works when we are executing a query in full, so ExecutePlan must disable parallel mode when it is asked to do partial execution. The previous logic for this involved passing down a flag (variously named execute_once or run_once) from callers of ExecutorRun or PortalRun. This is overcomplicated, and unsurprisingly some of the callers didn't get it right, since it requires keeping state that not all of them have handy; not to mention that the requirements for it were undocumented. That led to assertion failures in some corner cases. The only state we really need for this is the existing QueryDesc.already_executed flag, so let's just put all the responsibility in ExecutePlan. (It could have been done in ExecutorRun too, leading to a slightly shorter patch -- but if there's ever more than one caller of ExecutePlan, it seems better to have this logic in the subroutine than the callers.) This makes those ExecutorRun/PortalRun parameters unnecessary. In master it seems okay to just remove them, returning the API for those functions to what it was before parallelism. Such an API break is clearly not okay in stable branches, but for them we can just leave the parameters in place after documenting that they do nothing. Per report from Yugo Nagata, who also reviewed and tested this patch. Back-patch to all supported branches. Discussion: https://postgr.es/m/20241206062549.710dc01cf91224809dd6c0e1@sraoss.co.jp	1 year ago
Tom Lane	1a34cf0f48	Ensure that pg_amop/amproc entries depend on their lefttype/righttype. ... Usually an entry in pg_amop or pg_amproc does not need a dependency on its amoplefttype/amoprighttype/amproclefttype/amprocrighttype types, because there is an indirect dependency via the argument types of its referenced operator or procedure, or via the opclass it belongs to. However, for some support procedures in some index AMs, the argument types of the support procedure might not mention the column data type at all. Also, the amop/amproc entry might be treated as "loose" in the opfamily, in which case it lacks a dependency on any particular opclass; or it might be a cross-type entry having a reference to a datatype that is not its opclass' opcintype. The upshot of all this is that there are cases where a datatype can be dropped while leaving behind amop/amproc entries that mention it, because there is no path in pg_depend showing that those entries depend on that type. Such entries are harmless in normal activity, because they won't get used, but they cause problems for maintenance actions such as dropping the operator family. They also cause pg_dump to produce bogus output. The previous commit put a band-aid on the DROP OPERATOR FAMILY failure, but a real fix is needed. To fix, add pg_depend entries showing that a pg_amop/pg_amproc entry depends on its lefttype/righttype. To avoid bloating pg_depend too much, skip this if the referenced operator or function has that type as an input type. (I did not bother with considering the possible indirect dependency via the opclass' opcintype; at least in the reported case, that wouldn't help anyway.) Probably, the reason this has escaped notice for so long is that add-on datatypes and relevant opclasses/opfamilies are usually packaged as extensions nowadays, so that there's no way to drop a type without dropping the referencing opclasses/opfamilies too. Still, in the absence of pg_depend entries there's nothing that constrains DROP EXTENSION to drop the opfamily entries before the datatype, so it seems possible for a DROP failure to occur anyway. The specific case that was reported doesn't fail in v13, because v13 prefers to attach the support procedure to the opclass not the opfamily. But it's surely possible to construct other edge cases that do fail in v13, so patch that too. Per report from Yoran Heling. Back-patch to all supported branches. Discussion: https://postgr.es/m/Z1MVCOh1hprjK5Sf@gmai021	1 year ago
Tom Lane	d9d5e1b48e	Make getObjectDescription robust against dangling amproc type links. ... Yoran Heling reported a case where a data type could be dropped while references to its OID remain behind in pg_amproc. This causes getObjectDescription to fail, which blocks dropping the operator family (since our DROP code likes to construct descriptions of everything it's dropping). The proper fix for this requires adding more pg_depend entries. But to allow DROP to go through with already-corrupt catalogs, tweak getObjectDescription to print "???" for the type instead of failing when it processes such an entry. I changed the logic for pg_amop similarly, for consistency, although it is not known that the problem can manifest in pg_amop. Per report from Yoran Heling. Back-patch to all supported branches (although the problem may be unreachable in v13). Discussion: https://postgr.es/m/Z1MVCOh1hprjK5Sf@gmai021	1 year ago
Tom Lane	5882a4ba09	Fix is_digit labeling of to_timestamp's FFn format codes. ... 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	1 year ago
Tom Lane	d24eb0e91f	Avoid low-probability crash on out-of-memory. ... check_restrict_nonsystem_relation_kind() correctly uses guc_malloc() in v16 and later. But in older branches it must use malloc() directly, and it forgot to check for failure return. Faulty backpatching of 66e94448a. Karina Litskevich Discussion: https://postgr.es/m/CACiT8iZ=atkguKVbpN4HmJFMb4+T9yEowF5JuPZG8W+kkZ9L6w@mail.gmail.com	1 year ago
Thomas Munro	7d0b91a284	RelationTruncate() must set DELAY_CHKPT_START. ... Previously, it set only DELAY_CHKPT_COMPLETE. That was important, because it meant that if the XLOG_SMGR_TRUNCATE record preceded a XLOG_CHECKPOINT_ONLINE record in the WAL, then the truncation would also happen on disk before the XLOG_CHECKPOINT_ONLINE record was written. However, it didn't guarantee that the sync request for the truncation was processed before the XLOG_CHECKPOINT_ONLINE record was written. By setting DELAY_CHKPT_START, we guarantee that if an XLOG_SMGR_TRUNCATE record is written to WAL before the redo pointer of a concurrent checkpoint, the sync request queued by that operation must be processed by that checkpoint, rather than being left for the following one. This is a refinement of commit 412ad7a556. Back-patch to all supported releases, like that commit. Author: Robert Haas <robertmhaas@gmail.com> Reported-by: Thomas Munro <thomas.munro@gmail.com> Discussion: https://postgr.es/m/CA%2BhUKG%2B-2rjGZC2kwqr2NMLBcEBp4uf59QT1advbWYF_uc%2B0Aw%40mail.gmail.com	1 year ago
Tom Lane	52c7a44e95	Fix broken list-munging in ecpg's remove_variables(). ... The loops over cursor argument variables neglected to ever advance "prevvar". The code would accidentally do the right thing anyway when removing the first or second list entry, but if it had to remove the third or later entry then it would also remove all entries between there and the first entry. AFAICS this would only matter for cursors that reference out-of-scope variables, which is a weird Informix compatibility hack; between that and the lack of impact for short lists, it's not so surprising that nobody has complained. Nonetheless it's a pretty obvious bug. It would have been more obvious if these loops used a more standard coding style for chasing the linked lists --- this business with the "prev" pointer sometimes pointing at the current list entry is confusing and overcomplicated. So rather than just add a minimal band-aid, I chose to rewrite the loops in the same style we use elsewhere, where the "prev" pointer is NULL until we are dealing with a non-first entry and we save the "next" pointer at the top of the loop. (Two of the four loops touched here are not actually buggy, but it seems better to make them all look alike.) Coverity discovered this problem, but not until 2b41de4a5 added code to free no-longer-needed arguments structs. With that, the incorrect link updates are possibly touching freed memory, and it complained about that. Nonetheless the list corruption hazard is ancient, so back-patch to all supported branches.	1 year ago
Thomas Munro	fa92c18efe	Fix MinGW %d vs %lu warnings in back branches. ... Commit 352f6f2d used %d instead of %lu to format DWORD (unsigned long) with psprintf(). The _WIN32_WINNT value recently changed for MinGW in REL_15_STABLE (commit d700e8d7), so the code was suddenly being compiled, with warnings from gcc. The warnings were already fixed in 16+ by commits 495ed0ef and a9bc04b2 after the _WIN32_WINNT value was increase there. 14 and 13 didn't warn because they still use a lower value for MinGW, and supported versions of Visual Studio should compile the code in all live branches but don't check our format string. The change doesn't affect the result: sizeof(int) == sizeof(long) on this platform, and the values are computed with expressions that cannot exceed INT_MAX so were never interpreted as negative. Back-patch the formatting change from those commits into 13-15. This should turn CI's 15 branch green again and stop fairywren from warning about that on 15. Reported-by: Andres Freund <andres@anarazel.de> Reported-by: Peter Eisentraut <peter@eisentraut.org> Discussion: https://postgr.es/m/t2vjrcb3bloxf5qqvxjst6r7lvrefqyecxgt2koy5ho5b5glr2%40yuupmm6whgob	1 year ago
Thomas Munro	4112a25902	Skip SectionMemoryManager.h in cpluspluscheck. ... Commit 9044fc1d45 skipped SectionMemoryManager.h in headerscheck, and by extension also cpluspluscheck, because it's C++ and would fail both tests. That worked in master and REL_17_STABLE due to 7b8e2ae2fd, but older branches have a separate cpluspluscheck script. We need to copy the filtering rule into there too. This problem was being reported by CI's CompilerWarnings task in the 15 and 16 branches, but was a victim of alert fatigue syndrome (unrelated problems in the back-branches). Fix 16, and back-patch to 13, as those are the live branches that have a separate cpluspluscheck script.	1 year ago
Michael Paquier	3aae60c851	Revert "Handle better implicit transaction state of pipeline mode" ... This reverts commit d77f91214f on all stable branches, due to concerns regarding the compatility side effects this could create in a minor release. The change still exists on HEAD. Discussion: https://postgr.es/m/CA+TgmoZqRgeFTg4+Yf_CMRRXiHuNz1u6ZC4FvVk+rxw0RmOPnw@mail.gmail.com Backpatch-through: 13	1 year ago
Fujii Masao	0f13e1a78b	pgbench: Ensure previous progress message is fully cleared when updating. ... During pgbench's table initialization, progress updates could display leftover characters from the previous message if the new message was shorter. This commit resolves the issue by appending spaces to the current message to fully overwrite any remaining characters from the previous line. Back-patch to all the supported versions. Author: Yushi Ogiwara, Tatsuo Ishii, Fujii Masao Reviewed-by: Tatsuo Ishii, Fujii Masao Discussion: https://postgr.es/m/9a9b8b95b6a709877ae48ad5b0c59bb9@oss.nttdata.com	1 year ago
Peter Eisentraut	4c0e70fc30	Fix typo ... from commit 9044fc1d45	1 year ago
Peter Eisentraut	64c625ccc1	Exclude LLVM files from whitespace checks ... Commit 9044fc1d45 added some files from upstream LLVM. These files have different whitespace rules, which make the git whitespace checks powered by gitattributes fail. To fix, add those files to the exclude list.	1 year ago
Thomas Munro	1fd57e5bbf	If a C23 compiler is detected, try asking for C17. ... Branches before 16 can't be compiled with a C23 compiler (see deprecation warnings silenced by commit f9a56e72, and non-back-patchable changes made in 16 by commit 1c27d16e). Test __STDC_VERSION__, and if it's above C17 then try appending -std=gnu17. The test is done with the user's CFLAGS, so an acceptable language version can also be configured manually that way. This is done in branches 15 and older, back to 9.2, per policy of keeping them buildable with modern tools. Discussion: https://postgr.es/m/87o72eo9iu.fsf%40gentoo.org	1 year ago
Michael Paquier	2366211949	Handle better implicit transaction state of pipeline mode ... When using a pipeline, a transaction starts from the first command and is committed with a Sync message or when the pipeline ends. Functions like IsInTransactionBlock() or PreventInTransactionBlock() were already able to understand a pipeline as being in a transaction block, but it was not the case of CheckTransactionBlock(). This function is called for example to generate a WARNING for SET LOCAL, complaining that it is used outside of a transaction block. The current state of the code caused multiple problems, like: - SET LOCAL executed at any stage of a pipeline issued a WARNING, even if the command was at least second in line where the pipeline is in a transaction state. - LOCK TABLE failed when invoked at any step of a pipeline, even if it should be able to work within a transaction block. The pipeline protocol assumes that the first command of a pipeline is not part of a transaction block, and that any follow-up commands is considered as within a transaction block. This commit changes the backend so as an implicit transaction block is started each time the first Execute message of a pipeline has finished processing, with this implicit transaction block ended once a sync is processed. The checks based on XACT_FLAGS_PIPELINING in the routines checking if we are in a transaction block are not necessary: it is enough to rely on the existing ones. Some tests are added to pgbench, that can be backpatched down to v17 when \syncpipeline is involved and down to v14 where \startpipeline and \endpipeline are available. This is unfortunately limited regarding the error patterns that can be checked, but it provides coverage for various pipeline combinations to check if these succeed or fail. These tests are able to capture the case of SET LOCAL's WARNING. The author has proposed a different feature to improve the coverage by adding similar meta-commands to psql where error messages could be checked, something more useful for the cases where commands cannot be used in transaction blocks, like REINDEX CONCURRENTLY or VACUUM. This is considered as future work for v18~. Author: Anthonin Bonnefoy Reviewed-by: Jelte Fennema-Nio, Michael Paquier Discussion: https://postgr.es/m/CAO6_XqrWO8uNBQrSu5r6jh+vTGi5Oiyk4y8yXDORdE2jbzw8xw@mail.gmail.com Backpatch-through: 13	1 year ago
Tom Lane	a1168855e0	Fix NULLIF()'s handling of read-write expanded objects. ... If passed a read-write expanded object pointer, the EEOP_NULLIF code would hand that same pointer to the equality function and then (unless equality was reported) also return the same pointer as its value. This is no good, because a function that receives a read-write expanded object pointer is fully entitled to scribble on or even delete the object, thus corrupting the NULLIF output. (This problem is likely unobservable with the equality functions provided in core Postgres, but it's easy to demonstrate with one coded in plpgsql.) To fix, make sure the pointer passed to the equality function is read-only. We can still return the original read-write pointer as the NULLIF result, allowing optimization of later operations. Per bug #18722 from Alexander Lakhin. This has been wrong since we invented expanded objects, so back-patch to all supported branches. Discussion: https://postgr.es/m/18722-fd9e645448cc78b4@postgresql.org	1 year ago
Noah Misch	2690a4f5dd	Avoid "you don't own a lock of type ExclusiveLock" in GRANT TABLESPACE. ... 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	1 year ago
Tom Lane	2fc0199a50	Update configure probes for CFLAGS needed for ARM CRC instructions. ... On ARM platforms where the baseline CPU target lacks CRC instructions, we need to supply a -march flag to persuade the compiler to compile such instructions. It turns out that our existing choice of "-march=armv8-a+crc" has not worked for some time, because recent gcc will interpret that as selecting software floating point, and then will spit up if the platform requires hard-float ABI, as most do nowadays. The end result was to silently fall back to software CRC, which isn't very desirable since in practice almost all currently produced ARM chips do have hardware CRC. We can fix this by using "-march=armv8-a+crc+simd" to enable the correct ABI choice. (This has no impact on the code actually generated, since neither of the files we compile with this flag does any floating-point stuff, let alone SIMD.) Keep the test for "-march=armv8-a+crc" since that's required for soft-float ABI, but try that second since most platforms we're likely to build on use hard-float. Since this isn't working as-intended on the last several years' worth of gcc releases, back-patch to all supported branches. Discussion: https://postgr.es/m/4496616.iHFcN1HehY@portable-bastien	1 year ago
Peter Eisentraut	17d081a6f9	Add support for Tcl 9 ... Tcl 9 changed several API functions to take Tcl_Size, which is ptrdiff_t, instead of int, for 64-bit enablement. We have to change a few local variables to be compatible with that. We also provide a fallback typedef of Tcl_Size for older Tcl versions. The affected variables are used for quantities that will not approach values beyond the range of int, so this doesn't change any functionality. Reviewed-by: Tristan Partin <tristan@partin.io> Discussion: https://www.postgresql.org/message-id/flat/bce0fe54-75b4-438e-b42b-8e84bc7c0e9c%40eisentraut.org	1 year ago
Thomas Munro	e0874080c4	Assume that <stdbool.h> conforms to the C standard. ... Previously we checked "for <stdbool.h> that conforms to C99" using autoconf's AC_HEADER_STDBOOL macro. We've required C99 since PostgreSQL 12, so the test was redundant, and under C23 it was broken: autoconf 2.69's implementation doesn't understand C23's new empty header (the macros it's looking for went away, replaced by language keywords). Later autoconf versions fixed that, but let's just remove the anachronistic test. HAVE_STDBOOL_H and HAVE__BOOL will no longer be defined, but they weren't directly tested in core or likely extensions (except in 11, see below). PG_USE_STDBOOL (or USE_STDBOOL in 11 and 12) is still defined when sizeof(bool) is 1, which should be true on all modern systems. Otherwise we define our own bool type and values of size 1, which would fail to compile under C23 as revealed by the broken test. (We'll probably clean that dead code up in master, but here we want a minimal back-patchable change.) This came to our attention when GCC 15 recently started using using C23 by default and failed to compile the replacement code, as reported by Sam James and build farm animal alligator. Back-patch to all supported releases, and then two older versions that also know about <stdbool.h>, per the recently-out-of-support policy[1]. 12 requires C99 so it's much like the supported releases, but 11 only assumes C89 so it now uses AC_CHECK_HEADERS instead of the overly picky AC_HEADER_STDBOOL. (I could find no discussion of which historical systems had <stdbool.h> but failed the conformance test; if they ever existed, they surely aren't relevant to that policy's goals.) [1] https://wiki.postgresql.org/wiki/Committing_checklist#Policies Reported-by: Sam James <sam@gentoo.org> Reviewed-by: Peter Eisentraut <peter@eisentraut.org> (master version) Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (approach) Discussion: https://www.postgresql.org/message-id/flat/87o72eo9iu.fsf%40gentoo.org	1 year ago
Thomas Munro	7ca388fd0d	jit: Use -mno-outline-atomics for bitcode on ARM. ... If the executable's .o files were produced by a compiler (probably gcc) not using -moutline-atomics, and the corresponding .bc files were produced by clang using -moutline-atomics (probably by default), then the generated bitcode functions would have the target attribute "+outline-atomics", and could fail at runtime when inlined. If the target ISA at bitcode generation time was armv8-a (the most conservative aarch64 target, no LSE), then LLVM IR atomic instructions would generate calls to functions in libgcc.a or libclang_rt.*.a that switch between LL/SC and faster LSE instructions depending on a runtime AT_HWCAP check. Since the corresponding .o files didn't need those functions, they wouldn't have been included in the executable, and resolution would fail. At least Debian and Ubuntu are known to ship gcc and clang compilers that target armv8-a but differ on the use of outline atomics by default. Fix, by suppressing the outline atomics attribute in bitcode explicitly. Inline LL/SC instructions will be generated for atomic operations in bitcode built for armv8-a. Only configure scripts are adjusted for now, because the meson build system doesn't generate bitcode yet. This doesn't seem to be a new phenomenon, so real cases of functions using atomics that are inlined by JIT must be rare in the wild given how long it took for a bug report to arrive. The reported case could be reduced to: postgres=# set jit_inline_above_cost = 0; SET postgres=# set jit_above_cost = 0; SET postgres=# select pg_last_wal_receive_lsn(); WARNING: failed to resolve name __aarch64_swp4_acq_rel FATAL: fatal llvm error: Program used external function '__aarch64_swp4_acq_rel' which could not be resolved! The change doesn't affect non-ARM systems or later target ISAs. Back-patch to all supported releases. Reported-by: Alexander Kozhemyakin <a.kozhemyakin@postgrespro.ru> Discussion: https://postgr.es/m/18610-37bf303f904fede3%40postgresql.org	1 year ago
Álvaro Herrera	1c5fe56bc2	Fix newly introduced 010_keep_recycled_wals.pl ... It failed to set the archive_command as it desired because of a syntax problem. Oversight in commit 90bcc7c2db. This bug doesn't cause the test to fail, because the test only checks pg_rewind's output messages, not the actual outcome (and the outcome in both cases is that the file is kept, not deleted). But in either case the message about the file being kept is there, so it's hard to get excited about doing much more. Reported-by: Antonin Houska <ah@cybertec.at> Author: Alexander Kukushkin <cyberdemn@gmail.com> Discussion: https://postgr.es/m/7822.1732167825@antos	1 year ago
Álvaro Herrera	4a20c83798	Fix outdated bit in README.tuplock ... Apparently this information has been outdated since first committed, because we adopted a different implementation during development per reviews and this detail was not updated in the README. This has been wrong since commit 0ac5ad5134 introduced the file in 2013. Backpatch to all live branches. Reported-by: Will Mortensen <will@extrahop.com> Discussion: https://postgr.es/m/CAMpnoC6yEQ=c0Rdq-J7uRedrP7Zo9UMp6VZyP23QMT68n06cvA@mail.gmail.com	1 year ago
Tom Lane	3eb26524ca	Avoid assertion failure if a setop leaf query contains setops. ... 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	1 year ago
Tom Lane	44a4a521d0	Compare collations before merging UNION operations. ... In the dim past we figured it was okay to ignore collations when combining UNION set-operation nodes into a single N-way UNION operation. I believe that was fine at the time, but it stopped being fine when we added nondeterministic collations: the semantics of distinct-ness are affected by those. v17 made it even less fine by allowing per-child sorting operations to be merged via MergeAppend, although I think we accidentally avoided any live bug from that. Add a check that collations match before deciding that two UNION nodes are equivalent. I also failed to resist the temptation to comment plan_union_children() a little better. Back-patch to all supported branches (v13 now), since they all have nondeterministic collations. Discussion: https://postgr.es/m/3605568.1731970579@sss.pgh.pa.us	1 year ago
Tom Lane	4f5b14879d	Stamp 14.15.	1 year ago
Tom Lane	df1a2633b1	Fix recently-exposed portability issue in regex optimization. ... fixempties() counts the number of in-arcs in the regex NFA and then allocates an array of that many arc pointers. If the NFA contains no arcs, this amounts to malloc(0) for which some platforms return NULL. The code mistakenly treats that as indicating out-of-memory. Thus, we can get a bogus "out of memory" failure for some unsatisfiable regexes. This happens only in v15 and earlier, since bea3d7e38 switched to using palloc() rather than bare malloc(). And at least of the platforms in the buildfarm, only AIX seems to return NULL. So the impact is pretty narrow. But I don't especially want to ship code that is failing its own regression tests, so let's fix this for this week's releases. A quick code survey says that there is only the one place in src/backend/regex/ that is at risk of doing malloc(0), so we'll just band-aid that place. A more future-proof fix could be to install a malloc() wrapper similar to pg_malloc(). But this code seems unlikely to change much more in the affected branches, so that's probably overkill. The only known test case for this involves a complemented character class in a bracket expression, for example [^\s\S], and we didn't support that in v13. So it may be that the problem is unreachable in v13. But I'm not 100% sure of that, so patch v13 too. Discussion: https://postgr.es/m/661fd81b-f069-8f30-1a41-e195c57449b4@gmail.com	1 year ago
Tom Lane	290154105c	Release notes for 17.2, 16.6, 15.10, 14.15, 13.18, 12.22.	1 year ago
Tom Lane	099e711b77	Undo unintentional ABI break in struct ResultRelInfo. ... Commits aac2c9b4f et al. added a bool field to struct ResultRelInfo. That's no problem in the master branch, but in released branches care must be taken when modifying publicly-visible structs to avoid an ABI break for extensions. Frequently we solve that by adding the new field at the end of the struct, and that's what was done here. But ResultRelInfo has stricter constraints than just about any other node type in Postgres. Some executor APIs require extensions to index into arrays of ResultRelInfo, which means that any change whatever in sizeof(ResultRelInfo) causes a fatal ABI break. Fortunately, this is easy to fix, because the new field can be squeezed into available padding space instead --- indeed, that's where it was put in master, so this fix also removes a cross-branch coding variation. Per report from Pavan Deolasee. Patch v14-v17 only; earlier versions did not gain the extra field, nor is there any problem in master. Discussion: https://postgr.es/m/CABOikdNmVBC1LL6pY26dyxAS2f+gLZvTsNt=2XbcyG7WxXVBBQ@mail.gmail.com	1 year ago
Noah Misch	be062bfa54	Fix per-session activation of ALTER {ROLE|DATABASE} SET role. ... After commit 5a2fed911a, 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	1 year ago
Masahiko Sawada	26c4e89686	Fix a possibility of logical replication slot's restart_lsn going backwards. ... Previously LogicalIncreaseRestartDecodingForSlot() accidentally accepted any LSN as the candidate_lsn and candidate_valid after the restart_lsn of the replication slot was updated, so it potentially caused the restart_lsn to move backwards. A scenario where this could happen in logical replication is: after a logical replication restart, based on previous candidate_lsn and candidate_valid values in memory, the restart_lsn advances upon receiving a subscriber acknowledgment. Then, logical decoding restarts from an older point, setting candidate_lsn and candidate_valid based on an old RUNNING_XACTS record. Subsequent subscriber acknowledgments then update the restart_lsn to an LSN older than the current value. In the reported case, after WAL files were removed by a checkpoint, the retreated restart_lsn prevented logical replication from restarting due to missing WAL segments. This change essentially modifies the 'if' condition to 'else if' condition within the function. The previous code had an asymmetry in this regard compared to LogicalIncreaseXminForSlot(), which does almost the same thing for different fields. The WAL removal issue was reported by Hubert Depesz Lubaczewski. Backpatch to all supported versions, since the bug exists since 9.4 where logical decoding was introduced. Reviewed-by: Tomas Vondra, Ashutosh Bapat, Amit Kapila Discussion: https://postgr.es/m/Yz2hivgyjS1RfMKs%40depesz.com Discussion: https://postgr.es/m/85fff40e-148b-4e86-b921-b4b846289132%40vondra.me Backpatch-through: 13	1 year ago
Tom Lane	2bdd3b2489	Avoid assertion due to disconnected NFA sub-graphs in regex parsing. ... In commit 08c0d6ad6 which introduced "rainbow" arcs in regex NFAs, I didn't think terribly hard about what to do when creating the color complement of a rainbow arc. Clearly, the complement cannot match any characters, and I took the easy way out by just not building any arcs at all in the complement arc set. That mostly works, but Nikolay Shaplov found a case where it doesn't: if we decide to delete that sub-NFA later because it's inside a "{0}" quantifier, delsub() suffered an assertion failure. That's because delsub() relies on the target sub-NFA being fully connected. That was always true before, and the best fix seems to be to restore that property. Hence, invent a new arc type CANTMATCH that can be generated in place of an empty color complement, and drop it again later when we start NFA optimization. (At that point we don't need to do delsub() any more, and besides there are other cases where NFA optimization can lead to disconnected subgraphs.) It appears that this bug has no consequences in a non-assert-enabled build: there will be some transiently leaked NFA states/arcs, but they'll get cleaned up eventually. Still, we don't like assertion failures, so back-patch to v14 where rainbow arcs were introduced. Per bug #18708 from Nikolay Shaplov. Discussion: https://postgr.es/m/18708-f94f2599c9d2c005@postgresql.org	1 year ago
Álvaro Herrera	ba25358413	Avoid deleting critical WAL segments during pg_rewind ... Previously, in unlucky cases, it was possible for pg_rewind to remove certain WAL segments from the rewound demoted primary. In particular this happens if those files have been marked for archival (i.e., their .ready files were created) but not yet archived; the newly promoted node no longer has such files because of them having been recycled, but they are likely critical for recovery in the demoted node. If pg_rewind removes them, recovery is not possible anymore. Fix this by maintaining a hash table of files in this situation in the scan that looks for a checkpoint, which the decide_file_actions phase can consult so that it knows to preserve them. Backpatch to 14. The problem also exists in 13, but that branch was not blessed with commit eb00f1d4bf, so this patch is difficult to apply there. Users of older releases will just have to continue to be extra careful when rewinding. Co-authored-by: Полина Бунгина (Polina Bungina) <bungina@gmail.com> Co-authored-by: Alexander Kukushkin <cyberdemn@gmail.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Atsushi Torikoshi <torikoshia@oss.nttdata.com> Discussion: https://postgr.es/m/CAAtGL4AhzmBRsEsaDdz7065T+k+BscNadfTqP1NcPmsqwA5HBw@mail.gmail.com	1 year ago