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* Avoid using tuple from syscache for update of pg_database.datfrozenxidMichael Paquier2023-01-11
| | | | | | | | | | | | | | | | | | | | | | | | | pg_database.datfrozenxid gets updated using an in-place update at the end of vacuum or autovacuum. Since 96cdeae, as pg_database has a toast relation, it is possible for a pg_database tuple to have toast values if there is a large set of ACLs in place. In such a case, the in-place update would fail because of the flattening of the toast values done for the catcache entry fetched. Instead of using a copy from the catcache, this changes the logic to fetch the copy of the tuple by directly scanning pg_database. Note that before 96cdeae, attempting to insert such a tuple to pg_database would cause a "row is too big" error, so the end-of-vacuum problem was not reachable. This issue has been originally fixed in 947789f on v14~, and there have been reports about this problem on v12 and v13, causing failures at the end of VACUUM. This completes the fix on all the stable branches where pg_database can use a toast table, down to 12. Author: Ashwin Agrawal, Junfeng Yang Discussion: https://postgr.es/m/DM5PR0501MB38800D9E4605BCA72DD35557CCE10@DM5PR0501MB3880.namprd05.prod.outlook.com Discussion: https://postgr.es/m/Y70XNVbUWQsR2Car@paquier.xyz Backpatch-through: 12
* Fix typos in comments, code and documentationMichael Paquier2023-01-03
| | | | | | | | | | While on it, newlines are removed from the end of two elog() strings. The others are simple grammar mistakes. One comment in pg_upgrade referred incorrectly to sequences since a7e5457. Author: Justin Pryzby Discussion: https://postgr.es/m/20221230231257.GI1153@telsasoft.com Backpatch-through: 11
* Rethink handling of [Prevent|Is]InTransactionBlock in pipeline mode.Tom Lane2022-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commits f92944137 et al. made IsInTransactionBlock() set the XACT_FLAGS_NEEDIMMEDIATECOMMIT flag before returning "false", on the grounds that that kept its API promises equivalent to those of PreventInTransactionBlock(). This turns out to be a bad idea though, because it allows an ANALYZE in a pipelined series of commands to cause an immediate commit, which is unexpected. Furthermore, if we return "false" then we have another issue, which is that ANALYZE will decide it's allowed to do internal commit-and-start-transaction sequences, thus possibly unexpectedly committing the effects of previous commands in the pipeline. To fix the latter situation, invent another transaction state flag XACT_FLAGS_PIPELINING, which explicitly records the fact that we have executed some extended-protocol command and not yet seen a commit for it. Then, require that flag to not be set before allowing InTransactionBlock() to return "false". Having done that, we can remove its setting of NEEDIMMEDIATECOMMIT without fear of causing problems. This means that the API guarantees of IsInTransactionBlock now diverge from PreventInTransactionBlock, which is mildly annoying, but it seems OK given the very limited usage of IsInTransactionBlock. (In any case, a caller preferring the old behavior could always set NEEDIMMEDIATECOMMIT for itself.) For consistency also require XACT_FLAGS_PIPELINING to not be set in PreventInTransactionBlock. This too is meant to prevent commands such as CREATE DATABASE from silently committing previous commands in a pipeline. Per report from Peter Eisentraut. As before, back-patch to all supported branches (which sadly no longer includes v10). Discussion: https://postgr.es/m/65a899dd-aebc-f667-1d0a-abb89ff3abf8@enterprisedb.com
* Fix memory leak for hashing with nondeterministic collations.Jeff Davis2022-12-01
| | | | | | | Backpatch through 12, where nondeterministic collations were introduced (5e1963fb76). Backpatch-through: 12
* Improve heuristics for compressing the KnownAssignedXids array.Tom Lane2022-11-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, we'd compress only when the active range of array entries reached Max(4 * PROCARRAY_MAXPROCS, 2 * pArray->numKnownAssignedXids). If max_connections is large, the first term could result in not compressing for a long time, resulting in much wastage of cycles in hot-standby backends scanning the array to take snapshots. Get rid of that term, and just bound it to 2 * pArray->numKnownAssignedXids. That however creates the opposite risk, that we might spend too much effort compressing. Hence, consider compressing only once every 128 commit records. (This frequency was chosen by benchmarking. While we only tried one benchmark scenario, the results seem stable over a fairly wide range of frequencies.) Also, force compression when processing RecoveryInfo WAL records (which should be infrequent); the old code could perform compression then, but would do so only after the same array-range check as for the transaction-commit path. Also, opportunistically run compression if the startup process is about to wait for WAL, though not oftener than once a second. This should prevent cases where we waste lots of time by leaving the array not-compressed for long intervals due to low WAL traffic. Lastly, add a simple check to keep us from uselessly compressing when the array storage is already compact. Back-patch, as the performance problem is worse in pre-v14 branches than in HEAD. Simon Riggs and Michail Nikolaev, with help from Tom Lane and Andres Freund. Discussion: https://postgr.es/m/CALdSSPgahNUD_=pB_j=1zSnDBaiOtqVfzo8Ejt5J_k7qZiU1Tw@mail.gmail.com
* Make multixact error message more explicitAlvaro Herrera2022-11-24
| | | | | | | | | | | | | | There are recent reports involving a very old error message that we have no history of hitting -- perhaps a recently introduced bug. Improve the error message in an attempt to improve our chances of investigating the bug. Per reports from Dimos Stamatakis and Bob Krier. Backpatch to 11. Discussion: https://postgr.es/m/CO2PR0801MB2310579F65529380A4E5EDC0E20A9@CO2PR0801MB2310.namprd08.prod.outlook.com Discussion: https://postgr.es/m/17518-04e368df5ad7f2ee@postgresql.org
* Replace RelationOpenSmgr() with RelationGetSmgr().Tom Lane2022-11-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a back-patch of the v15-era commit f10f0ae42 into older supported branches. The idea is to design out bugs in which an ill-timed relcache flush clears rel->rd_smgr partway through some code sequence that wasn't expecting that. We had another report today of a corner case that reliably crashes v14 under debug_discard_caches (nee CLOBBER_CACHE_ALWAYS), and therefore would crash once in a blue moon in the field. We're unlikely to get rid of all such code paths unless we adopt the more rigorous coding rules instituted by f10f0ae42. Therefore, even though this is a bit invasive, it's time to back-patch. Some comfort can be taken in the fact that f10f0ae42 has been in v15 for 16 months without problems. I left the RelationOpenSmgr macro present in the back branches, even though no core code should use it anymore, in order to not break third-party extensions in minor releases. Such extensions might opt to start using RelationGetSmgr instead, to reduce their code differential between v15 and earlier branches. This carries a hazard of failing to compile against headers from existing minor releases. However, once compiled the extension should work fine even with such releases, because RelationGetSmgr is a "static inline" function so it creates no link-time dependency. So depending on distribution practices, that might be an OK tradeoff. Per report from Spyridon Dimitrios Agathos. Original patch by Amul Sul. Discussion: https://postgr.es/m/CAFM5RaqdgyusQvmWkyPYaWMwoK5gigdtW-7HcgHgOeAw7mqJ_Q@mail.gmail.com Discussion: https://postgr.es/m/CANiYTQsU7yMFpQYnv=BrcRVqK_3U3mtAzAsJCaqtzsDHfsUbdQ@mail.gmail.com
* Fix cleanup lock acquisition in SPLIT_ALLOCATE_PAGE replay.Amit Kapila2022-11-14
| | | | | | | | | | | | | | | | During XLOG_HASH_SPLIT_ALLOCATE_PAGE replay, we were checking for a cleanup lock on the new bucket page after acquiring an exclusive lock on it and raising a PANIC error on failure. However, it is quite possible that checkpointer can acquire the pin on the same page before acquiring a lock on it, and then the replay will lead to an error. So instead, directly acquire the cleanup lock on the new bucket page during XLOG_HASH_SPLIT_ALLOCATE_PAGE replay operation. Reported-by: Andres Freund Author: Robert Haas Reviewed-By: Amit Kapila, Andres Freund, Vignesh C Backpatch-through: 11 Discussion: https://postgr.es/m/20220810022617.fvjkjiauaykwrbse@awork3.anarazel.de
* Fix theoretical torn page hazard.Jeff Davis2022-11-11
| | | | | | | | | | | | | | | | | | | | | | | | The original report was concerned with a possible inconsistency between the heap and the visibility map, which I was unable to confirm. The concern has been retracted. However, there did seem to be a torn page hazard when using checksums. By not setting the heap page LSN during redo, the protections of minRecoveryPoint were bypassed. Fixed, along with a misleading comment. It may have been impossible to hit this problem in practice, because it would require a page tear between the checksum and the flags, so I am marking this as a theoretical risk. But, as discussed, it did violate expectations about the page LSN, so it may have other consequences. Backpatch to all supported versions. Reported-by: Konstantin Knizhnik Reviewed-by: Konstantin Knizhnik Discussion: https://postgr.es/m/fed17dac-8cb8-4f5b-d462-1bb4908c029e@garret.ru Backpatch-through: 11
* Doc: add comments about PreventInTransactionBlock/IsInTransactionBlock.Tom Lane2022-11-09
| | | | | | | | | | | | | Add a little to the header comments for these functions to make it clearer what guarantees about commit behavior are provided to callers. (See commit f92944137 for context.) Although this is only a comment change, it's really documentation aimed at authors of extensions, so it seems appropriate to back-patch. Yugo Nagata and Tom Lane, per further discussion of bug #17434. Discussion: https://postgr.es/m/17434-d9f7a064ce2a88a3@postgresql.org
* Fix ordering issue with WAL operations in GIN fast insert pathMichael Paquier2022-10-26
| | | | | | | | | | | | | | | | | | | | | | | | Contrary to what is documented in src/backend/access/transam/README, ginHeapTupleFastInsert() had a few ordering issues with the way it does its WAL operations when inserting items in its fast path. First, when using a separate list, XLogBeginInsert() was being always called before START_CRIT_SECTION(), and in this case a second thing was wrong when merging lists, as an exclusive lock was taken on the tail page *before* calling XLogBeginInsert(). Finally, when inserting items into a tail page, the order of XLogBeginInsert() and START_CRIT_SECTION() was reversed. This commit addresses all these issues by moving the calls of XLogBeginInsert() after all the pages logged are locked and pinned, within a critical section. This has been applied first only on HEAD as of 56b6625, but as per discussion with Tom Lane and Álvaro Herrera, a backpatch is preferred to keep all the branches consistent and to respect the transam's README where we can. Author: Matthias van de Meent, Zhang Mingli Discussion: https://postgr.es/m/CAEze2WhL8uLMqynnnCu1LAPwxD5RKEo0nHV+eXGg_N6ELU88HQ@mail.gmail.com Backpatch-through: 10
* Avoid improbable PANIC during heap_update, redux.Tom Lane2022-09-30
| | | | | | | | | | | | | | | | | | | | Commit 34f581c39 intended to ensure that RelationGetBufferForTuple would acquire a visibility-map page pin in case the otherBuffer's all-visible bit had become set since we last had lock on that page. But I missed a case: when we're extending the relation, VM concerns were dealt with only in the relatively-less-likely case that we fail to conditionally lock the otherBuffer. I think I'd believed that we couldn't need to worry about it if the conditional lock succeeds, which is true for the target buffer; but the otherBuffer was unlocked for awhile so its bit might be set anyway. So we need to do the GetVisibilityMapPins dance, and then also recheck the page's free space, in both cases. Per report from Jaime Casanova. Back-patch to v12 as the previous patch was (although there's still no evidence that the bug is reachable pre-v14). Discussion: https://postgr.es/m/E1lWLjP-00006Y-Ml@gemulon.postgresql.org
* Fix race condition where heap_delete() fails to pin VM page.Jeff Davis2022-09-22
| | | | | | | | | | Similar to 5f12bc94dc, the code must re-check PageIsAllVisible() after buffer lock is re-acquired. Backpatching to the same version, 12. Discussion: https://postgr.es/m/CAEP4nAw9jYQDKd_5Y+-s2E4YiUJq1vqiikFjYGpLShtp-K3gag@mail.gmail.com Reported-by: Robins Tharakan Reviewed-by: Robins Tharakan Backpatch-through: 12
* Suppress variable-set-but-not-used warnings from clang 15.Tom Lane2022-09-20
| | | | | | | | | | | | | | | | | | | | | | | | clang 15+ will issue a set-but-not-used warning when the only use of a variable is in autoincrements (e.g., "foo++;"). That's perfectly sensible, but it detects a few more cases that we'd not noticed before. Silence the warnings with our usual methods, such as PG_USED_FOR_ASSERTS_ONLY, or in one case by actually removing a useless variable. One thing that we can't nicely get rid of is that with %pure-parser, Bison emits "yynerrs" as a local variable that falls foul of this warning. To silence those, I inserted "(void) yynerrs;" in the top-level productions of affected grammars. Per recently-established project policy, this is a candidate for back-patching into out-of-support branches: it suppresses annoying compiler warnings but changes no behavior. Hence, back-patch to 9.5, which is as far as these patches go without issues. (A preliminary check shows that the prior branches need some other set-but-not-used cleanups too, so I'll leave them for another day.) Discussion: https://postgr.es/m/514615.1663615243@sss.pgh.pa.us
* Backpatch nbtree page deletion hardening.Peter Geoghegan2022-09-05
| | | | | | | | | | | | | | | | | | | Postgres 14 commit 5b861baa taught nbtree VACUUM to tolerate buggy opclasses. VACUUM's inability to locate a to-be-deleted page's downlink in the parent page was logged instead of throwing an error. VACUUM could just press on with vacuuming the index, and vacuuming the table as a whole. There are now anecdotal reports of this error causing problems that were much more disruptive than the underlying index corruption ever could be. Anything that makes VACUUM unable to make forward progress against one table/index ultimately risks making the system enter xidStopLimit mode. There is no good reason to take any chances here, so backpatch the hardening commit. Author: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-Wzm9HR6Pow=t-iQa57zT8qmX6_M4h14F-pTtb=xFDW5FBA@mail.gmail.com Backpatch: 10-13 (all supported versions that lacked the hardening)
* Prevent WAL corruption after a standby promotion.Robert Haas2022-08-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | When a PostgreSQL instance performing archive recovery but not using standby mode is promoted, and the last WAL segment that it attempted to read ended in a partial record, the previous code would create invalid WAL on the new timeline. The WAL from the previously timeline would be copied to the new timeline up until the end of the last valid record, but instead of beginning to write WAL at immediately afterwards, the promoted server would write an overwrite contrecord at the beginning of the next segment. The end of the previous segment would be left as all-zeroes, resulting in failures if anything tried to read WAL from that file. The root of the issue is that ReadRecord() decides whether to set abortedRecPtr and missingContrecPtr based on the value of StandbyMode, but ReadRecord() switches to a new timeline based on the value of ArchiveRecoveryRequested. We shouldn't try to write an overwrite contrecord if we're switching to a new timeline, so change the test in ReadRecod() to check ArchiveRecoveryRequested instead. Code fix by Dilip Kumar. Comments by me incorporating suggested language from Álvaro Herrera. Further review from Kyotaro Horiguchi and Sami Imseih. Discussion: http://postgr.es/m/CAFiTN-t7umki=PK8dT1tcPV=mOUe2vNhHML6b3T7W7qqvvajjg@mail.gmail.com Discussion: http://postgr.es/m/FB0DEA0B-E14E-43A0-811F-C1AE93D00FF3%40amazon.com
* BRIN: mask BRIN_EVACUATE_PAGE for WAL consistency checkingAlvaro Herrera2022-08-05
| | | | | | | | | | | | | | | | That bit is unlogged and therefore it's wrong to consider it in WAL page comparison. Add a test that tickles the case, as branch testing technology allows. This has been a problem ever since wal consistency checking was introduced (commit a507b86900f6 for pg10), so backpatch to all supported branches. Author: 王海洋 (Haiyang Wang) <wanghaiyang.001@bytedance.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Discussion: https://postgr.es/m/CACciXAD2UvLMOhc4jX9VvOKt7DtYLr3OYRBhvOZ-jRxtzc_7Jg@mail.gmail.com Discussion: https://postgr.es/m/CACciXADOfErX9Bx0nzE_SkdfXr6Bbpo5R=v_B6MUTEYW4ya+cg@mail.gmail.com
* Add HINT for restartpoint race with KeepFileRestoredFromArchive().Noah Misch2022-08-05
| | | | | | | | | | The five commits ending at cc2c7d65fc27e877c9f407587b0b92d46cd6dd16 closed this race condition for v15+. For v14 through v10, add a HINT to discourage studying the cosmetic problem. Reviewed by Kyotaro Horiguchi and David Steele. Discussion: https://postgr.es/m/20220731061747.GA3692882@rfd.leadboat.com
* Fix replay of create database records on standbyAlvaro Herrera2022-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Crash recovery on standby may encounter missing directories when replaying database-creation WAL records. Prior to this patch, the standby would fail to recover in such a case; however, the directories could be legitimately missing. Consider the following sequence of commands: CREATE DATABASE DROP DATABASE DROP TABLESPACE If, after replaying the last WAL record and removing the tablespace directory, the standby crashes and has to replay the create database record again, crash recovery must be able to continue. A fix for this problem was already attempted in 49d9cfc68bf4, but it was reverted because of design issues. This new version is based on Robert Haas' proposal: any missing tablespaces are created during recovery before reaching consistency. Tablespaces are created as real directories, and should be deleted by later replay. CheckRecoveryConsistency ensures they have disappeared. The problems detected by this new code are reported as PANIC, except when allow_in_place_tablespaces is set to ON, in which case they are WARNING. Apart from making tests possible, this gives users an escape hatch in case things don't go as planned. Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Author: Asim R Praveen <apraveen@pivotal.io> Author: Paul Guo <paulguo@gmail.com> Reviewed-by: Anastasia Lubennikova <lubennikovaav@gmail.com> (older versions) Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com> (older versions) Reviewed-by: Michaël Paquier <michael@paquier.xyz> Diagnosed-by: Paul Guo <paulguo@gmail.com> Discussion: https://postgr.es/m/CAEET0ZGx9AvioViLf7nbR_8tH9-=27DN5xWJ2P9-ROH16e4JUA@mail.gmail.com
* Allow "in place" tablespaces.Alvaro Herrera2022-07-27
| | | | | | | | | | | | | | | | | | | | | | This is a backpatch to branches 10-14 of the following commits: 7170f2159fb2 Allow "in place" tablespaces. c6f2f01611d4 Fix pg_basebackup with in-place tablespaces. f6f0db4d6240 Fix pg_tablespace_location() with in-place tablespaces 7a7cd84893e0 doc: Remove mention to in-place tablespaces for pg_tablespace_location() 5344723755bd Remove unnecessary Windows-specific basebackup code. In-place tablespaces were introduced as a testing helper mechanism, but they are going to be used for a bugfix in WAL replay to be backpatched to all stable branches. I (Álvaro) had to adjust some code to account for lack of get_dirent_type() in branches prior to 14. Author: Thomas Munro <thomas.munro@gmail.com> Author: Michaël Paquier <michael@paquier.xyz> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/20220722081858.omhn2in5zt3g4nek@alvherre.pgsql
* Force immediate commit after CREATE DATABASE etc in extended protocol.Tom Lane2022-07-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a few commands that "can't run in a transaction block", meaning that if they complete their processing but then we fail to COMMIT, we'll be left with inconsistent on-disk state. However, the existing defenses for this are only watertight for simple query protocol. In extended protocol, we didn't commit until receiving a Sync message. Since the client is allowed to issue another command instead of Sync, we're in trouble if that command fails or is an explicit ROLLBACK. In any case, sitting in an inconsistent state while waiting for a client message that might not come seems pretty risky. This case wasn't reachable via libpq before we introduced pipeline mode, but it's always been an intended aspect of extended query protocol, and likely there are other clients that could reach it before. To fix, set a flag in PreventInTransactionBlock that tells exec_execute_message to force an immediate commit. This seems to be the approach that does least damage to existing working cases while still preventing the undesirable outcomes. While here, add some documentation to protocol.sgml that explicitly says how to use pipelining. That's latent in the existing docs if you know what to look for, but it's better to spell it out; and it provides a place to document this new behavior. Per bug #17434 from Yugo Nagata. It's been wrong for ages, so back-patch to all supported branches. Discussion: https://postgr.es/m/17434-d9f7a064ce2a88a3@postgresql.org
* Fix assertion failure and segmentation fault in backup code.Fujii Masao2022-07-20
| | | | | | | | | | | | | | | | | | | | | | When a non-exclusive backup is canceled, do_pg_abort_backup() is called and resets some variables set by pg_backup_start (pg_start_backup in v14 or before). But previously it forgot to reset the session state indicating whether a non-exclusive backup is in progress or not in this session. This issue could cause an assertion failure when the session running BASE_BACKUP is terminated after it executed pg_backup_start and pg_backup_stop (pg_stop_backup in v14 or before). Also it could cause a segmentation fault when pg_backup_stop is called after BASE_BACKUP in the same session is canceled. This commit fixes the issue by making do_pg_abort_backup reset that session state. Back-patch to all supported branches. Author: Fujii Masao Reviewed-by: Kyotaro Horiguchi, Masahiko Sawada, Michael Paquier, Robert Haas Discussion: https://postgr.es/m/3374718f-9fbf-a950-6d66-d973e027f44c@oss.nttdata.com
* Fix visibility check when XID is committed in CLOG but not in procarray.Heikki Linnakangas2022-06-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TransactionIdIsInProgress had a fast path to return 'false' if the single-item CLOG cache said that the transaction was known to be committed. However, that was wrong, because a transaction is first marked as committed in the CLOG but doesn't become visible to others until it has removed its XID from the proc array. That could lead to an error: ERROR: t_xmin is uncommitted in tuple to be updated or for an UPDATE to go ahead without blocking, before the previous UPDATE on the same row was made visible. The window is usually very short, but synchronous replication makes it much wider, because the wait for synchronous replica happens in that window. Another thing that makes it hard to hit is that it's hard to get such a commit-in-progress transaction into the single item CLOG cache. Normally, if you call TransactionIdIsInProgress on such a transaction, it determines that the XID is in progress without checking the CLOG and without populating the cache. One way to prime the cache is to explicitly call pg_xact_status() on the XID. Another way is to use a lot of subtransactions, so that the subxid cache in the proc array is overflown, making TransactionIdIsInProgress rely on pg_subtrans and CLOG checks. This has been broken ever since it was introduced in 2008, but the race condition is very hard to hit, especially without synchronous replication. There were a couple of reports of the error starting from summer 2021, but no one was able to find the root cause then. TransactionIdIsKnownCompleted() is now unused. In 'master', remove it, but I left it in place in backbranches in case it's used by extensions. Also change pg_xact_status() to check TransactionIdIsInProgress(). Previously, it only checked the CLOG, and returned "committed" before the transaction was actually made visible to other queries. Note that this also means that you cannot use pg_xact_status() to reproduce the bug anymore, even if the code wasn't fixed. Report and analysis by Konstantin Knizhnik. Patch by Simon Riggs, with the pg_xact_status() change added by me. Author: Simon Riggs Reviewed-by: Andres Freund Discussion: https://www.postgresql.org/message-id/flat/4da7913d-398c-e2ad-d777-f752cf7f0bbb%40garret.ru
* Silence compiler warnings from some older compilers.Tom Lane2022-06-01
| | | | | | | | | | | | Since a117cebd6, some older gcc versions issue "variable may be used uninitialized in this function" complaints for brin_summarize_range. Silence that using the same coding pattern as in bt_index_check_internal; arguably, a117cebd6 had too narrow a view of which compilers might give trouble. Nathan Bossart and Tom Lane. Back-patch as the previous commit was. Discussion: https://postgr.es/m/20220601163537.GA2331988@nathanxps13
* Fix control file update done in restartpoints still running after promotionMichael Paquier2022-05-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a cluster is promoted (aka the control file shows a state different than DB_IN_ARCHIVE_RECOVERY) while CreateRestartPoint() is still processing, this function could miss an update of the control file for "checkPoint" and "checkPointCopy" but still do the recycling and/or removal of the past WAL segments, assuming that the to-be-updated LSN values should be used as reference points for the cleanup. This causes a follow-up restart attempting crash recovery to fail with a PANIC on a missing checkpoint record if the end-of-recovery checkpoint triggered by the promotion did not complete while the cluster abruptly stopped or crashed before the completion of this checkpoint. The PANIC would be caused by the redo LSN referred in the control file as located in a segment already gone, recycled by the previous restartpoint with "checkPoint" out-of-sync in the control file. This commit fixes the update of the control file during restartpoints so as "checkPoint" and "checkPointCopy" are updated even if the cluster has been promoted while a restartpoint is running, to be on par with the set of WAL segments actually recycled in the end of CreateRestartPoint(). 7863ee4 has fixed this problem already on master, but the release timing of the latest point versions did not let me enough time to study and fix that on all the stable branches. Reported-by: Fujii Masao, Rui Zhao Author: Kyotaro Horiguchi Reviewed-by: Nathan Bossart, Michael Paquier Discussion: https://postgr.es/m/20220316.102444.2193181487576617583.horikyota.ntt@gmail.com Backpatch-through: 10
* Make relation-enumerating operations be security-restricted operations.Noah Misch2022-05-09
| | | | | | | | | | | | | | | | | | When a feature enumerates relations and runs functions associated with all found relations, the feature's user shall not need to trust every user having permission to create objects. BRIN-specific functionality in autovacuum neglected to account for this, as did pg_amcheck and CLUSTER. An attacker having permission to create non-temp objects in at least one schema could execute arbitrary SQL functions under the identity of the bootstrap superuser. CREATE INDEX (not a relation-enumerating operation) and REINDEX protected themselves too late. This change extends to the non-enumerating amcheck interface. Back-patch to v10 (all supported versions). Sergey Shinderuk, reviewed (in earlier versions) by Alexander Lakhin. Reported by Alexander Lakhin. Security: CVE-2022-1552
* Rethink the delay-checkpoint-end mechanism in the back-branches.Robert Haas2022-04-14
| | | | | | | | | | | | | | | | | | | | The back-patch of commit bbace5697df12398e87ffd9879171c39d27f5b33 had the unfortunate effect of changing the layout of PGPROC in the back-branches, which could break extensions. This happened because it changed the delayChkpt from type bool to type int. So, change it back, and add a new bool delayChkptEnd field instead. The new field should fall within what used to be padding space within the struct, and so hopefully won't cause any extensions to break. Per report from Markus Wanner and discussion with Tom Lane and others. Patch originally by me, somewhat revised by Markus Wanner per a suggestion from Michael Paquier. A very similar patch was developed by Kyotaro Horiguchi, but I failed to see the email in which that was posted before writing one of my own. Discussion: http://postgr.es/m/CA+Tgmoao-kUD9c5nG5sub3F7tbo39+cdr8jKaOVEs_1aBWcJ3Q@mail.gmail.com Discussion: http://postgr.es/m/20220406.164521.17171257901083417.horikyota.ntt@gmail.com
* Prevent access to no-longer-pinned buffer in heapam_tuple_lock().Tom Lane2022-04-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | heap_fetch() used to have a "keep_buf" parameter that told it to return ownership of the buffer pin to the caller after finding that the requested tuple TID exists but is invisible to the specified snapshot. This was thoughtlessly removed in commit 5db6df0c0, which broke heapam_tuple_lock() (formerly EvalPlanQualFetch) because that function needs to do more accesses to the tuple even if it's invisible. The net effect is that we would continue to touch the page for a microsecond or two after releasing pin on the buffer. Usually no harm would result; but if a different session decided to defragment the page concurrently, we could see garbage data and mistakenly conclude that there's no newer tuple version to chain up to. (It's hard to say whether this has happened in the field. The bug was actually found thanks to a later change that allowed valgrind to detect accesses to non-pinned buffers.) The most reasonable way to fix this is to reintroduce keep_buf, although I made it behave slightly differently: buffer ownership is passed back only if there is a valid tuple at the requested TID. In HEAD, we can just add the parameter back to heap_fetch(). To avoid an API break in the back branches, introduce an additional function heap_fetch_extended() in those branches. In HEAD there is an additional, less obvious API change: tuple->t_data will be set to NULL in all cases where buffer ownership is not returned, in particular when the tuple exists but fails the time qual (and !keep_buf). This is to defend against any other callers attempting to access non-pinned buffers. We concluded that making that change in back branches would be more likely to introduce problems than cure any. In passing, remove a comment about heap_fetch that was obsoleted by 9a8ee1dc6. Per bug #17462 from Daniil Anisimov. Back-patch to v12 where the bug was introduced. Discussion: https://postgr.es/m/17462-9c98a0f00df9bd36@postgresql.org
* Suppress "variable 'pagesaving' set but not used" warning.Tom Lane2022-04-06
| | | | | | | With asserts disabled, late-model clang notices that this variable is incremented but never otherwise read. Discussion: https://postgr.es/m/3171401.1649275153@sss.pgh.pa.us
* Revert "Fix replay of create database records on standby"Alvaro Herrera2022-03-29
| | | | | | | This reverts commit 49d9cfc68bf4. The approach taken by this patch has problems, so we'll come up with a radically different fix. Discussion: https://postgr.es/m/CA+TgmoYcUPL+WOJL2ZzhH=zmrhj0iOQ=iCFM0SuYqBbqZEamEg@mail.gmail.com
* Fix replay of create database records on standbyAlvaro Herrera2022-03-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Crash recovery on standby may encounter missing directories when replaying create database WAL records. Prior to this patch, the standby would fail to recover in such a case. However, the directories could be legitimately missing. Consider a sequence of WAL records as follows: CREATE DATABASE DROP DATABASE DROP TABLESPACE If, after replaying the last WAL record and removing the tablespace directory, the standby crashes and has to replay the create database record again, the crash recovery must be able to move on. This patch adds a mechanism similar to invalid-page tracking, to keep a tally of missing directories during crash recovery. If all the missing directory references are matched with corresponding drop records at the end of crash recovery, the standby can safely continue following the primary. Backpatch to 13, at least for now. The bug is older, but fixing it in older branches requires more careful study of the interactions with commit e6d8069522c8, which appeared in 13. A new TAP test file is added to verify the condition. However, because it depends on commit d6d317dbf615, it can only be added to branch master. I (Álvaro) manually verified that the code behaves as expected in branch 14. It's a bit nervous-making to leave the code uncovered by tests in older branches, but leaving the bug unfixed is even worse. Also, the main reason this fix took so long is precisely that we couldn't agree on a good strategy to approach testing for the bug, so perhaps this is the best we can do. Diagnosed-by: Paul Guo <paulguo@gmail.com> Author: Paul Guo <paulguo@gmail.com> Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Author: Asim R Praveen <apraveen@pivotal.io> Discussion: https://postgr.es/m/CAEET0ZGx9AvioViLf7nbR_8tH9-=27DN5xWJ2P9-ROH16e4JUA@mail.gmail.com
* Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.Robert Haas2022-03-24
| | | | | | | | | | | | | | | | If TRUNCATE causes some buffers to be invalidated and thus the checkpoint does not flush them, TRUNCATE must also ensure that the corresponding files are truncated on disk. Otherwise, a replay from the checkpoint might find that the buffers exist but have the wrong contents, which may cause replay to fail. Report by Teja Mupparti. Patch by Kyotaro Horiguchi, per a design suggestion from Heikki Linnakangas, with some changes to the comments by me. Review of this and a prior patch that approached the issue differently by Heikki Linnakangas, Andres Freund, Álvaro Herrera, Masahiko Sawada, and Tom Lane. Discussion: http://postgr.es/m/BYAPR06MB6373BF50B469CA393C614257ABF00@BYAPR06MB6373.namprd06.prod.outlook.com
* Fix "missing continuation record" after standby promotionAlvaro Herrera2022-03-23
| | | | | | | | | | | | | | Invalidate abortedRecPtr and missingContrecPtr after a missing continuation record is successfully skipped on a standby. This fixes a PANIC caused when a recently promoted standby attempts to write an OVERWRITE_RECORD with an LSN of the previously read aborted record. Backpatch to 10 (all stable versions). Author: Sami Imseih <simseih@amazon.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/44D259DE-7542-49C4-8A52-2AB01534DCA9@amazon.com
* Fix race between DROP TABLESPACE and checkpointing.Thomas Munro2022-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commands like ALTER TABLE SET TABLESPACE may leave files for the next checkpoint to clean up. If such files are not removed by the time DROP TABLESPACE is called, we request a checkpoint so that they are deleted. However, there is presently a window before checkpoint start where new unlink requests won't be scheduled until the following checkpoint. This means that the checkpoint forced by DROP TABLESPACE might not remove the files we expect it to remove, and the following ERROR will be emitted: ERROR: tablespace "mytblspc" is not empty To fix, add a call to AbsorbSyncRequests() just before advancing the unlink cycle counter. This ensures that any unlink requests forwarded prior to checkpoint start (i.e., when ckpt_started is incremented) will be processed by the current checkpoint. Since AbsorbSyncRequests() performs memory allocations, it cannot be called within a critical section, so we also need to move SyncPreCheckpoint() to before CreateCheckPoint()'s critical section. This is an old bug, so back-patch to all supported versions. Author: Nathan Bossart <nathandbossart@gmail.com> Reported-by: Nathan Bossart <nathandbossart@gmail.com> Reviewed-by: Thomas Munro <thomas.munro@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20220215235845.GA2665318%40nathanxps13
* Clean up assorted failures under clang's -fsanitize=undefined checks.Tom Lane2022-03-03
| | | | | | | | | | | | | | | | | | | | | | Most of these are cases where we could call memcpy() or other libc functions with a NULL pointer and a zero count, which is forbidden by POSIX even though every production version of libc allows it. We've fixed such things before in a piecemeal way, but apparently never made an effort to try to get them all. I don't claim that this patch does so either, but it gets every failure I observe in check-world, using clang 12.0.1 on current RHEL8. numeric.c has a different issue that the sanitizer doesn't like: "ln(-1.0)" will compute log10(0) and then try to assign the resulting -Inf to an integer variable. We don't actually use the result in such a case, so there's no live bug. Back-patch to all supported branches, with the idea that we might start running a buildfarm member that tests this case. This includes back-patching c1132aae3 (Check the size in COPY_POINTER_FIELD), which previously silenced some of these issues in copyfuncs.c. Discussion: https://postgr.es/m/CALNJ-vT9r0DSsAOw9OXVJFxLENoVS_68kJ5x0p44atoYH+H4dg@mail.gmail.com
* WAL log unchanged toasted replica identity key attributes.Amit Kapila2022-02-14
| | | | | | | | | | | | | | | Currently, during UPDATE, the unchanged replica identity key attributes are not logged separately because they are getting logged as part of the new tuple. But if they are stored externally then the untoasted values are not getting logged as part of the new tuple and logical replication won't be able to replicate such UPDATEs. So we need to log such attributes as part of the old_key_tuple during UPDATE. Reported-by: Haiying Tang Author: Dilip Kumar and Amit Kapila Reviewed-by: Alvaro Herrera, Haiying Tang, Andres Freund Backpatch-through: 10 Discussion: https://postgr.es/m/OS0PR01MB611342D0A92D4F4BF26C0F47FB229@OS0PR01MB6113.jpnprd01.prod.outlook.com
* fsync pg_logical/mappings in CheckPointLogicalRewriteHeap().Andres Freund2022-01-21
| | | | | | | | | | | While individual logical rewrite files were synced to disk, the directory was not. On some filesystems that could lead to loosing directory entries after a crash. Reported-By: Tom Lane <tgl@sss.pgh.pa.us> Author: Nathan Bossart <bossartn@amazon.com> Discussion: https://postgr.es/m/867F2E29-2782-4869-970E-B984C6D35A8F@amazon.com Backpatch: 10-
* Fix one-off bug causing missing commit timestamps for subtransactionsMichael Paquier2022-01-21
| | | | | | | | | | | | | | | | | | | The logic in charge of writing commit timestamps (enabled with track_commit_timestamp) for subtransactions had a one-bug bug, where it would be possible that commit timestamps go missing for the last subtransaction committed. While on it, simplify a bit the iteration logic in the loop writing the commit timestamps, as per suggestions from Kyotaro Horiguchi and Tom Lane, so as some variable initializations are not part of the loop itself. Issue introduced in 73c986a. Analyzed-by: Alex Kingsborough Author: Alex Kingsborough, Kyotaro Horiguchi Discussion: https://postgr.es/m/73A66172-4050-4F2A-B7F1-13508EDA2144@amazon.com Backpatch-through: 10
* Fix silly mistake in AssertAlvaro Herrera2022-01-04
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* Allow special SKIP LOCKED condition in Assert()Alvaro Herrera2022-01-04
| | | | | | | | | | | | | | | | | Under concurrency, it is possible for two sessions to be merrily locking and releasing a tuple and marking it again as HEAP_XMAX_INVALID all the while a third session attempts to lock it, miserably fails at it, and then contemplates life, the universe and everything only to eventually fail an assertion that said bit is not set. Before SKIP LOCKED that was indeed a reasonable expectation, but alas! commit df630b0dd5ea falsified it. This bug is as old as time itself, and even older, if you think time begins with the oldest supported branch. Therefore, backpatch to all supported branches. Author: Simon Riggs <simon.riggs@enterprisedb.com> Discussion: https://postgr.es/m/CANbhV-FeEwMnN8yuMyss7if1ZKjOKfjcgqB26n8pqu1e=q0ebg@mail.gmail.com
* Remove assertion for replication origins in PREPARE TRANSACTIONMichael Paquier2021-12-14
| | | | | | | | | | | | | | | | | When using replication origins, pg_replication_origin_xact_setup() is an optional choice to be able to set a LSN and a timestamp to mark the origin, which would be additionally added to WAL for transaction commits or aborts (including 2PC transactions). An assertion in the code path of PREPARE TRANSACTION assumed that this data should always be set, so it would trigger when using replication origins without setting up an origin LSN. Some tests are added to cover more this kind of scenario. Oversight in commit 1eb6d65. Per discussion with Amit Kapila and Masahiko Sawada. Discussion: https://postgr.es/m/YbbBfNSvMm5nIINV@paquier.xyz Backpatch-through: 11
* Fix corruption of toast indexes with REINDEX CONCURRENTLYMichael Paquier2021-12-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | REINDEX CONCURRENTLY run on a toast index or a toast relation could corrupt the target indexes rebuilt, as a backend running in parallel that manipulates toast values would directly release the lock on the toast relation when its local operation is done, rather than releasing the lock once the transaction that manipulated the toast values committed. The fix done here is simple: we now hold a ROW EXCLUSIVE lock on the toast relation when saving or deleting a toast value until the transaction working on them is committed, so as a concurrent reindex happening in parallel would be able to wait for any activity and see any new rows inserted (or deleted). An isolation test is added to check after the case fixed here, which is a bit fancy by design as it relies on allow_system_table_mods to rename the toast table and its index to fixed names. This way, it is possible to reindex them directly without any dependency on the OID of the underlying relation. Note that this could not use a DO block either, as REINDEX CONCURRENTLY cannot be run in a transaction block. The test is backpatched down to 13, where it is possible, thanks to c4a7a39, to use allow_system_table_mods in a test suite. Reported-by: Alexey Ermakov Analyzed-by: Andres Freund, Noah Misch Author: Michael Paquier Reviewed-by: Nathan Bossart Discussion: https://postgr.es/m/17268-d2fb426e0895abd4@postgresql.org Backpatch-through: 12
* Fix determination of broken LSN in OVERWRITTEN_CONTRECORDAlvaro Herrera2021-11-26
| | | | | | | | | | | | | | In commit ff9f111bce24 I mixed up inconsistent definitions of the LSN of the first record in a page, when the previous record ends exactly at the page boundary. The correct LSN is adjusted to skip the WAL page header; I failed to use that when setting XLogReaderState->overwrittenRecPtr, so at WAL replay time VerifyOverwriteContrecord would refuse to let replay continue past that record. Backpatch to 10. 9.6 also contains this bug, but it's no longer being maintained. Discussion: https://postgr.es/m/45597.1637694259@sss.pgh.pa.us
* Fix parallel operations that prevent oldest xmin from advancing.Amit Kapila2021-11-19
| | | | | | | | | | | | | | | | | While determining xid horizons, we skip over backends that are running Vacuum. We also ignore Create Index Concurrently, or Reindex Concurrently for the purposes of computing Xmin for Vacuum. But we were not setting the flags corresponding to these operations when they are performed in parallel which was preventing Xid horizon from advancing. The optimization related to skipping Create Index Concurrently, or Reindex Concurrently operations was implemented in PG-14 but the fix is the same for the Parallel Vacuum as well so back-patched till PG-13. Author: Masahiko Sawada Reviewed-by: Amit Kapila Backpatch-through: 13 Discussion: https://postgr.es/m/CAD21AoCLQqgM1sXh9BrDFq0uzd3RBFKi=Vfo6cjjKODm0Onr5w@mail.gmail.com
* Report any XLogReadRecord() error in XlogReadTwoPhaseData().Noah Misch2021-11-11
| | | | | | | | | | Buildfarm members kittiwake and tadarida have witnessed errors at this site. The site discarded key facts. Back-patch to v10 (all supported versions). Reviewed by Michael Paquier and Tom Lane. Discussion: https://postgr.es/m/20211107013157.GB790288@rfd.leadboat.com
* Fix typoAlvaro Herrera2021-11-08
| | | | | | | Introduced in 1d97d3d0867f. Co-authored-by: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/83641f59-d566-b33e-ef21-a272a98675aa@gmail.com
* Fix ordering of items in nbtree error message.Peter Geoghegan2021-10-27
| | | | | | Oversight in commit a5213adf. Backpatch: 13-, just like commit a5213adf.
* Further harden nbtree posting split code.Peter Geoghegan2021-10-27
| | | | | | | | | | | Add more defensive checks around posting list split code. These should detect corruption involving duplicate table TIDs earlier and more reliably than any existing check. Follow up to commit 8f72bbac. Discussion: https://postgr.es/m/CAH2-WzkrSY_kjyd1_M5xJK1uM0govJXMxPn8JUSvwcUOiHuWVw@mail.gmail.com Backpatch: 13-, where nbtree deduplication was introduced.
* Fix CREATE INDEX CONCURRENTLY for the newest prepared transactions.Noah Misch2021-10-23
| | | | | | | | | | | | | | | | | | | The purpose of commit 8a54e12a38d1545d249f1402f66c8cde2837d97c was to fix this, and it sufficed when the PREPARE TRANSACTION completed before the CIC looked for lock conflicts. Otherwise, things still broke. As before, in a cluster having used CIC while having enabled prepared transactions, queries that use the resulting index can silently fail to find rows. It may be necessary to reindex to recover from past occurrences; REINDEX CONCURRENTLY suffices. Fix this for future index builds by making CIC wait for arbitrarily-recent prepared transactions and for ordinary transactions that may yet PREPARE TRANSACTION. As part of that, have PREPARE TRANSACTION transfer locks to its dummy PGPROC before it calls ProcArrayClearTransaction(). Back-patch to 9.6 (all supported versions). Andrey Borodin, reviewed (in earlier versions) by Andres Freund. Discussion: https://postgr.es/m/01824242-AA92-4FE9-9BA7-AEBAFFEA3D0C@yandex-team.ru
* Reset properly snapshot export state during transaction abortMichael Paquier2021-10-18
| | | | | | | | | | | | | | | | | | | | | | | | During a replication slot creation, an ERROR generated in the same transaction as the one creating a to-be-exported snapshot would have left the backend in an inconsistent state, as the associated static export snapshot state was not being reset on transaction abort, but only on the follow-up command received by the WAL sender that created this snapshot on replication slot creation. This would trigger inconsistency failures if this session tried to export again a snapshot, like during the creation of a replication slot. Note that a snapshot export cannot happen in a transaction block, so there is no need to worry resetting this state for subtransaction aborts. Also, this inconsistent state would very unlikely show up to users. For example, one case where this could happen is an out-of-memory error when building the initial snapshot to-be-exported. Dilip found this problem while poking at a different patch, that caused an error in this code path for reasons unrelated to HEAD. Author: Dilip Kumar Reviewed-by: Michael Paquier, Zhihong Yu Discussion: https://postgr.es/m/CAFiTN-s0zA1Kj0ozGHwkYkHwa5U0zUE94RSc_g81WrpcETB5=w@mail.gmail.com Backpatch-through: 9.6