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* Fix incorrect format placeholdersPeter Eisentraut2021-12-29
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* Move parallel vacuum code to vacuumparallel.c.Amit Kapila2021-12-23
| | | | | | | | | | | | | | | This commit moves parallel vacuum related code to a new file commands/vacuumparallel.c so that any table AM supporting indexes can utilize parallel vacuum in order to call index AM callbacks (ambulkdelete and amvacuumcleanup) with parallel workers. Another reason for this refactoring is that the parallel vacuum isn't specific to heap so it doesn't make sense to keep this code in heap/vacuumlazy.c. Author: Masahiko Sawada, based on suggestion from Andres Freund Reviewed-by: Hou Zhijie, Amit Kapila, Haiying Tang Discussion: https://www.postgresql.org/message-id/20211030212101.ae3qcouatwmy7tbr%40alap3.anarazel.de
* Change ProcSendSignal() to take pgprocno.Thomas Munro2021-12-16
| | | | | | | | | | | Instead of referring to target backends by pid, use pgprocno. This means that we don't have to scan the ProcArray and we can drop some special case code for dealing with the startup process. Discussion: https://postgr.es/m/CA%2BhUKGLYRyDaneEwz5Uya_OgFLMx5BgJfkQSD%3Dq9HmwsfRRb-w%40mail.gmail.com Reviewed-by: Soumyadeep Chakraborty <soumyadeep2007@gmail.com> Reviewed-by: Ashwin Agrawal <ashwinstar@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de>
* 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
* Remove InitXLOGAccess().Robert Haas2021-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | It's not great that RecoveryInProgress() calls InitXLOGAccess(), because a status inquiry function typically shouldn't have the side effect of performing initializations. We could fix that by calling InitXLOGAccess() from some other place, but instead, let's remove it altogether. One thing InitXLogAccess() did is initialize wal_segment_size, but it doesn't need to do that. In the postmaster, PostmasterMain() calls LocalProcessControlFile(), and all child processes will inherit that value -- except in EXEC_BACKEND bulds, but then each backend runs SubPostmasterMain() which also calls LocalProcessControlFile(). The other thing InitXLOGAccess() did is update RedoRecPtr and doPageWrites, but that's not critical, because all code that uses them will just retry if it turns out that they've changed. The only difference is that most code will now see an initial value that is definitely invalid instead of one that might have just been way out of date, but that will only happen once per backend lifetime, so it shouldn't be a big deal. Patch by me, reviewed by Nathan Bossart, Michael Paquier, Andres Freund, Heikki Linnakangas, and Álvaro Herrera. Discussion: http://postgr.es/m/CA+TgmoY7b65qRjzHN_tWUk8B4sJqk1vj1d31uepVzmgPnZKeLg@mail.gmail.com
* Default to log_checkpoints=on, log_autovacuum_min_duration=10mRobert Haas2021-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | The idea here is that when a performance problem is known to have occurred at a certain point in time, it's a good thing if there is some information available from the logs to help figure out what might have happened around that time. This change attracted an above-average amount of dissent, because it means that a server with default settings will produce some amount of log output even if nothing has gone wrong. However, by my count, the mailing list discussion had about twice as many people in favor of the change as opposed. The reasons for believing that the extra log output is not an issue in practice are: (1) the rate at which messages can be generated by this setting is bounded to one every few minutes on a properly-configured system and (2) production systems tend to have a lot more junk in the log from that due to failed connection attempts, ERROR messages generated by application activity, and the like. Bharath Rupireddy, reviewed by Fujii Masao and by me. Many other people commented on the thread, but as far as I can see that was discussion of the merits of the change rather than review of the patch. Discussion: https://postgr.es/m/CALj2ACX-rW_OeDcp4gqrFUAkf1f50Fnh138dmkd0JkvCNQRKGA@mail.gmail.com
* Remove mention of TimeLineID update from commentsDaniel Gustafsson2021-12-01
| | | | | | | | Commit 4a92a1c3d removed the TimeLineID update from RecoveryInProgress, update comments accordingly. Author: Amul Sul <sulamul@gmail.com> Discussion: https://postgr.es/m/CAAJ_b96wyzs8N45jc-kYd-bTE02hRWQieLZRpsUtNbhap7_PuQ@mail.gmail.com
* Increase size of shared memory for pg_commit_tsAlvaro Herrera2021-11-30
| | | | | | | | | | Like 5364b357fb11 did for pg_commit, change the formula used to determine number of pg_commit_ts buffers, which helps performance with larger servers. Discussion: https://postgr.es/m/20210115220744.GA24457@alvherre.pgsql Reviewed-by: Noah Misch <noah@leadboat.com> Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
* Centralize timestamp computation of control file on updatesMichael Paquier2021-11-29
| | | | | | | | | | | | | | | | | | | This commit moves the timestamp computation of the control file within the routine of src/common/ in charge of updating the backend's control file, which is shared by multiple frontend tools (pg_rewind, pg_checksums and pg_resetwal) and the backend itself. This change has as direct effect to update the control file's timestamp when writing the control file in pg_rewind and pg_checksums, something that is helpful to keep track of control file updates for those operations, something also tracked by the backend at startup within its logs. This part is arguably a bug, as ControlFileData->time should be updated each time a new version of the control file is written, but this is a behavior change so no backpatch is done. Author: Amul Sul Reviewed-by: Nathan Bossart, Michael Paquier, Bharath Rupireddy Discussion: https://postgr.es/m/CAAJ_b97nd_ghRpyFV9Djf9RLXkoTbOUqnocq11WGq9TisX09Fw@mail.gmail.com
* Replace random(), pg_erand48(), etc with a better PRNG API and algorithm.Tom Lane2021-11-28
| | | | | | | | | | | | | | | | | | | Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating a bunch of platform dependencies as well as fundamentally-obsolete PRNG code. In addition, this API replacement will ease replacing the algorithm again in future, should that become necessary. xoroshiro128** is a few percent slower than the drand48 family, but it can produce full-width 64-bit random values not only 48-bit, and it should be much more trustworthy. It's likely to be noticeably faster than the platform's random(), depending on which platform you are thinking about; and we can have non-global state vectors easily, unlike with random(). It is not cryptographically strong, but neither are the functions it replaces. Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
* 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
* Replace straggling uses of ReadRecPtr/EndRecPtr.Andres Freund2021-11-24
| | | | | | | d2ddfa681db removed ReadRecPtr/EndRecPtr, but two uses within an #ifdef WAL_DEBUG escaped. Discussion: https://postgr.es/m/20211124231206.gbadj5bblcljb6d5@alap3.anarazel.de
* xlog.c: Remove global variables ReadRecPtr and EndRecPtr.Robert Haas2021-11-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In most places, the variables necessarily store the same value as the eponymous members of the XLogReaderState that we use during WAL replay, because ReadRecord() assigns the values from the structure members to the global variables just after XLogReadRecord() returns. However, XLogBeginRead() adjusts the structure members but not the global variables, so after XLogBeginRead() and before the completion of XLogReadRecord() the values can differ. Otherwise, they must be identical. According to my analysis, the only place where either variable is referenced at a point where it might not have the same value as the structure member is the refrence to EndRecPtr within XLogPageRead. Therefore, at every other place where we are using the global variable, we can just switch to using the structure member instead, and remove the global variable. However, we can, and in fact should, do this in XLogPageRead() as well, because at that point in the code, the global variable will actually store the start of the record we want to read - either because it's where the last WAL record ended, or because the read position has been changed using XLogBeginRead since the last record was read. The structure member, on the other hand, will already have been updated to point to the end of the record we just read. Elsewhere, the latter is what we use as an argument to emode_for_corrupt_record(), so we should do the same here. This part of the patch is perhaps a bug fix, but I don't think it has any important consequences, so no back-patch. The point here is just to continue to whittle down the entirely excessive use of global variables in xlog.c. Discussion: http://postgr.es/m/CA+Tgmoao96EuNeSPd+hspRKcsCddu=b1h-QNRuKfY8VmfNQdfg@mail.gmail.com
* Fix corner-case failure to detect improper timeline switch.Robert Haas2021-11-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rescanLatestTimeLine() contains a guard against switching to a timeline that forked off from the current one prior to the current recovery point, but that guard does not work if the timeline switch occurs before the first WAL recod (which must be the checkpoint record) is read. Without this patch, an improper timeline switch is therefore possible in such cases. This happens because rescanLatestTimeLine() relies on the global variable EndRecPtr to understand the current position of WAL replay. However, EndRecPtr at this point in the code contains the endpoint of the last-replayed record, not the startpoint or endpoint of the record being replayed now. Thus, before any records have been replayed, it's zero, which causes the sanity check to always pass. To fix, pass down the correct timeline explicitly. The EndRecPtr value we want is the one from the xlogreader, which will be the starting position of the record we're about to try to read, rather than the global variable, which is the ending position of the last record we successfully read. They're usually the same, but not in the corner case described here. No back-patch, because in v14 and earlier branhes, we were using the wrong TLI here as well as the wrong LSN. In master, that was fixed by commit 4a92a1c3d1c361ffb031ed05bf65b801241d7cdd, but that and it's prerequisite patches are too invasive to back-patch for such a minor issue. Patch by me, reviewed by Amul Sul. Discussion: http://postgr.es/m/CA+Tgmoao96EuNeSPd+hspRKcsCddu=b1h-QNRuKfY8VmfNQdfg@mail.gmail.com
* Be more specific about OOM in XLogReaderAllocateAlvaro Herrera2021-11-22
| | | | | | | | | | | A couple of spots can benefit from an added errdetail(), which matches what we were already doing in other places; and those that cannot withstand errdetail() can get a more descriptive primary message. Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Discussion: https://postgr.es/m/CALj2ACV+cX1eM03GfcA=ZMLXh5fSn1X1auJLz3yuS1duPSb9QA@mail.gmail.com
* Report wait events for local shell commands like archive_command.Fujii Masao2021-11-22
| | | | | | | | | This commit introduces new wait events for archive_command, archive_cleanup_command, restore_command and recovery_end_command. Author: Fujii Masao Reviewed-by: Bharath Rupireddy, Michael Paquier Discussion: https://postgr.es/m/4ca4f920-6b48-638d-08b2-93598356f5d3@oss.nttdata.com
* Remove global variable "LastRec" in xlog.cMichael Paquier2021-11-17
| | | | | | | | | This variable is used only by StartupXLOG() now, so let's make it local to simplify the code. Author: Amul Sul Reviewed-by: Tom Lane, Michael Paquier Discussion: https://postgr.es/m/CAAJ_b96Qd023itERBRN9Z7P2saNDT3CYvGuMO8RXwndVNN6z7g@mail.gmail.com
* Move InitXLogInsert() call from InitXLOGAccess() to BaseInit().Robert Haas2021-11-16
| | | | | | | | | | | | | | | | | At present, there is an undocumented coding rule that you must call RecoveryInProgress(), or do something else that results in a call to InitXLogInsert(), before trying to write WAL. Otherwise, the WAL construction buffers won't be initialized, resulting in failures. Since it's not good to rely on a status inquiry function like RecoveryInProgress() having the side effect of initializing critical data structures, instead do the initialization eariler, when the backend first starts up. Patch by me. Reviewed by Nathan Bossart and Michael Paquier. Discussion: http://postgr.es/m/CA+TgmoY7b65qRjzHN_tWUk8B4sJqk1vj1d31uepVzmgPnZKeLg@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
* Improve performance of pgarch_readyXlog() with many status files.Robert Haas2021-11-11
| | | | | | | | | | | | | | | | | | | 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
* More cleanup of 'ThisTimeLineID'.Robert Haas2021-11-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | In XLogCtlData, rename the structure member ThisTimeLineID to InsertTimeLineID and update the comments to make clear that it's only expected to be set after recovery is complete. In StartupXLOG, replace the local variables ThisTimeLineID and PrevTimeLineID with new local variables replayTLI and newTLI. In the old scheme, ThisTimeLineID was the replay TLI until we created a new timeline, and after that the replay TLI was in PrevTimeLineID. Now, replayTLI is the TLI from which we last replayed WAL throughout the entire function, and newTLI is either that, or the new timeline created upon promotion. Remove some misleading comments from the comment block just above where recoveryTargetTimeLineGoal and friends are declared. It's become incorrect, not only because ThisTimeLineID as a variable is now gone, but also because the rmgr code does not care about ThisTimeLineID and has not since what used to be the TLI field in the page header was repurposed to store the page checksum. Add a comment GetFlushRecPtr that it's only supposed to be used in normal running, and an assertion to verify that this is so. Per some ideas from Michael Paquier and some of my own. Review by Michael Paquier also. Discussion: http://postgr.es/m/CA+TgmoY1a2d1AnVR3tJcKmGGkhj7GGrwiNwjtKr21dxOuLBzCQ@mail.gmail.com
* Silence uninitialized-variable warning.Tom Lane2021-11-07
| | | | | | | | Quite a few buildfarm animals are warning about this, and lapwing is actually failing (because -Werror). It's a false positive AFAICS, so no need to do more than zero the variable to start with. Discussion: https://postgr.es/m/YYXJnUxgw9dZKxlX@paquier.xyz
* Change ThisTimeLineID from a global variable to a local variable.Robert Haas2021-11-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | StartupXLOG() still has ThisTimeLineID as a local variable, but the remaining code in xlog.c now needs to the relevant TimeLineID by some other means. Mostly, this means that we now pass it as a function parameter to a bunch of functions where we didn't previously. However, a few cases require special handling: - In functions that might be called by outside callers who wouldn't necessarily know what timeline to specify, we get the timeline ID from shared memory. XLogCtl->ThisTimeLineID can be used in most cases since recovery is known to have completed by the time those functions are called. In xlog_redo(), we can use XLogCtl->replayEndTLI. - XLogFileClose() needs to know the TLI of the open logfile. Do that with a new global variable openLogTLI. While someone could argue that this is just trading one global variable for another, the new one has a far more narrow purposes and is referenced in just a few places. - read_backup_label() now returns the TLI that it obtains by parsing the backup_label file. Previously, ReadRecord() could be called to parse the checkpoint record without ThisTimeLineID having been initialized. Now, the timeline is passed down, and I didn't want to pass an uninitialized variable; this change lets us avoid that. The old coding didn't seem to have any practical consequences that we need to worry about, but this is cleaner. - In BootstrapXLOG(), it's just a constant. Patch by me, reviewed and tested by Michael Paquier, Amul Sul, and Álvaro Herrera. Discussion: https://postgr.es/m/CA+TgmobfAAqhfWa1kaFBBFvX+5CjM=7TE=n4r4Q1o2bjbGYBpA@mail.gmail.com
* Remove all use of ThisTimeLineID global variable outside of xlog.cRobert Haas2021-11-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All such code deals with this global variable in one of three ways. Sometimes the same functions use it in more than one of these ways at the same time. First, sometimes it's an implicit argument to one or more functions being called in xlog.c or elsewhere, and must be set to the appropriate value before calling those functions lest they misbehave. In those cases, it is now passed as an explicit argument instead. Second, sometimes it's used to obtain the current timeline after the end of recovery, i.e. the timeline to which WAL is being written and flushed. Such code now calls GetWALInsertionTimeLine() or relies on the new out parameter added to GetFlushRecPtr(). Third, sometimes it's used during recovery to store the current replay timeline. That can change, so such code must generally update the value before each use. It can still do that, but must now use a local variable instead. The net effect of these changes is to reduce by a fair amount the amount of code that is directly accessing this global variable. That's good, because history has shown that we don't always think clearly about which timeline ID it's supposed to contain at any given point in time, or indeed, whether it has been or needs to be initialized at any given point in the code. Patch by me, reviewed and tested by Michael Paquier, Amul Sul, and Álvaro Herrera. Discussion: https://postgr.es/m/CA+TgmobfAAqhfWa1kaFBBFvX+5CjM=7TE=n4r4Q1o2bjbGYBpA@mail.gmail.com
* Move MarkCurrentTransactionIdLoggedIfAny() out of the critical section.Amit Kapila2021-11-02
| | | | | | | | | | | We don't modify any shared state in this function which could cause problems for any concurrent session. This will make it look similar to the other updates for the same structure (TransactionState) which avoids confusion for future readers of code. Author: Dilip Kumar Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/E1mSoYz-0007Fh-D9@gemulon.postgresql.org
* Replace XLOG_INCLUDE_XID flag with a more localized flag.Amit Kapila2021-11-02
| | | | | | | | | | | | | | | | Commit 0bead9af484c introduced XLOG_INCLUDE_XID flag to indicate that the WAL record contains subXID-to-topXID association. It uses that flag later to mark in CurrentTransactionState that top-xid is logged so that we should not try to log it again with the next WAL record in the current subtransaction. However, we can use a localized variable to pass that information. In passing, change the related function and variable names to make them consistent with what the code is actually doing. Author: Dilip Kumar Reviewed-by: Alvaro Herrera, Amit Kapila Discussion: https://postgr.es/m/E1mSoYz-0007Fh-D9@gemulon.postgresql.org
* Fix typos in commentsDaniel Gustafsson2021-10-27
| | | | | Author: Peter Smith <smithpb2250@gmail.com> Discussion: https://postgr.es/m/CAHut+PsN_gmKu-KfeEb9NDARoTPbs4AN4PPu=6LZXFZRJ13SEw@mail.gmail.com
* Initialize variable to placate compiler.Robert Haas2021-10-25
| | | | | | Per Nathan Bossart. Discussion: http://postgr.es/m/FECEE7FC-CB74-45A9-BB24-89FEE52A9585@amazon.com
* Report progress of startup operations that take a long time.Robert Haas2021-10-25
| | | | | | | | | | | | | | | | | | | | | | | | Users sometimes get concerned whe they start the server and it emits a few messages and then doesn't emit any more messages for a long time. Generally, what's happening is either that the system is taking a long time to apply WAL, or it's taking a long time to reset unlogged relations, or it's taking a long time to fsync the data directory, but it's not easy to tell which is the case. To fix that, add a new 'log_startup_progress_interval' setting, by default 10s. When an operation that is known to be potentially long-running takes more than this amount of time, we'll log a status update each time this interval elapses. To avoid undesirable log chatter, don't log anything about WAL replay when in standby mode. Nitin Jadhav and Robert Haas, reviewed by Amul Sul, Bharath Rupireddy, Justin Pryzby, Michael Paquier, and Álvaro Herrera. Discussion: https://postgr.es/m/CA+TgmoaHQrgDFOBwgY16XCoMtXxsrVGFB2jNCvb7-ubuEe1MGg@mail.gmail.com Discussion: https://postgr.es/m/CAMm1aWaHF7VE69572_OLQ+MgpT5RUiUDgF1x5RrtkJBLdpRj3Q@mail.gmail.com
* StartupXLOG: Don't repeatedly disable/enable local xlog insertion.Robert Haas2021-10-25
| | | | | | | | | | | | | | | | | | | All the code that runs in the startup process to write WAL records before that's allowed generally is now consecutive, so there's no reason to shut the facility to write WAL locally off and then turn it on again three times in a row. Unfortunately, this requires a slight kludge in the checkpointer, which needs to separately enable writing WAL in order to write the checkpoint record. Because that code might run in the same process as StartupXLOG() if we are in single-user mode, we must save/restore the state of the LocalXLogInsertAllowed flag. Hopefully, we'll be able to eliminate this wart in further refactoring, but it's not too bad anyway. Amul Sul, with modifications by me. Discussion: http://postgr.es/m/CAAJ_b97fysj6sRSQEfOHj-y8Jfd5uPqOgO74qast89B4WfD+TA@mail.gmail.com
* StartupXLOG: Call CleanupAfterArchiveRecovery after XLogReportParameters.Robert Haas2021-10-25
| | | | | | | | | | | | | | | This does a better job grouping related operations together, since all of the WAL records that we need to write prior to allowing WAL writes generally and written by a single uninterrupted stretch of code. Since CleanupAfterArchiveRecovery() just (1) runs recovery_end_command, (2) removes non-parent xlog files, and (3) archives any final partial segment, this should be safe, because all of those things are pretty much unrelated to the WAL record written by XLogReportParameters(). Amul Sul, per a suggestion from me Discussion: http://postgr.es/m/CAAJ_b97fysj6sRSQEfOHj-y8Jfd5uPqOgO74qast89B4WfD+TA@mail.gmail.com
* 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
* Postpone some end-of-recovery operations related to allowing WAL.Robert Haas2021-10-14
| | | | | | | | | | | | | | | | | | | | | | | CreateOverwriteContrecordRecord(), UpdateFullPageWrites(), PerformRecoveryXLogAction(), and CleanupAfterArchiveRecovery() are moved somewhat later in StartupXLOG(). This is preparatory work for a future patch that wants to allow recovery to end at one time and only later start to allow WAL writes. To do that, it's necessary to separate code that has to do with allowing WAL writes from other things that need to happen simply because recovery is ending, such as initializing shared memory data structures that depend on information that might not be accurate before redo is complete. This commit does not achieve that goal, but it is a step in that direction. For example, there are a few different bits of code that write things into WAL once we have finished recovery, and with this change, those bits of code are closer to each other than previously, with fewer unrelated bits of code interspersed. Robert Haas and Amul Sul Discussion: http://postgr.es/m/CAAJ_b97abMuq=470Wahun=aS1PHTSbStHtrjjPaD-C0YQ1AqVw@mail.gmail.com
* Refactor some end-of-recovery code out of StartupXLOG().Robert Haas2021-10-13
| | | | | | | | | | | | | | | | | | Create a new function PerformRecoveryXLogAction() and move the code which either writes an end-of-recovery record or requests a checkpoint there. Also create a new function CleanupAfterArchiveRecovery() to perform a few tasks that we want to do after we've actually exited archive recovery but before we start accepting new WAL writes. More refactoring of this file is planned, but this commit is just straightforward code movement to make StartupXLOG() a little bit shorter and a little bit easier to understand. Robert Haas and Amul Sul Discussion: http://postgr.es/m/CAAJ_b97abMuq=470Wahun=aS1PHTSbStHtrjjPaD-C0YQ1AqVw@mail.gmail.com
* Make recovery report error message when invalid page header is found.Fujii Masao2021-10-06
| | | | | | | | | | | | | | | | | | | | | | | | Commit 0668719801 changed XLogPageRead() so that it validated the page header, if invalid page header was found reset the error message and retried reading the page, to fix the scenario where streaming standby got stuck at a continuation record. This change hid the error message about invalid page header, which would make it harder for users to investigate what the actual issue was found in WAL. To fix the issue, this commit makes XLogPageRead() report the error message when invalid page header is found. When not in standby mode, an invalid page header should cause recovery to end, not retry reading the page, so XLogPageRead() doesn't need to validate the page header for the retry. Instead, ReadPageInternal() should be responsible for the validation in that case. Therefore this commit changes XLogPageRead() so that if not in standby mode it doesn't validate the page header for the retry. Reported-by: Yugo Nagata Author: Yugo Nagata, Kyotaro Horiguchi Reviewed-by: Ranier Vilela, Fujii Masao Discussion: https://postgr.es/m/20210718045505.32f463ed6c227111038d8ae4@sraoss.co.jp
* Fix duplicate words in commentsDaniel Gustafsson2021-10-04
| | | | | | | Remove accidentally duplicated words in code comments. Author: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Discussion: https://postgr.es/m/87bl45t0co.fsf@wibble.ilmari.org
* Fix snapshot builds during promotion of hot standby node with 2PCMichael Paquier2021-10-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some specific logic is done at the end of recovery when involving 2PC transactions: 1) Call RecoverPreparedTransactions(), to recover the state of 2PC transactions into memory (re-acquire locks, etc.). 2) ShutdownRecoveryTransactionEnvironment(), to move back to normal operations, mainly cleaning up recovery locks and KnownAssignedXids (including any 2PC transaction tracked previously). 3) Switch XLogCtl->SharedRecoveryState to RECOVERY_STATE_DONE, which is the tipping point for any process calling RecoveryInProgress() to check if the cluster is still in recovery or not. Any snapshot taken between steps 2) and 3) would be empty, causing any transaction relying on a snapshot at this point to potentially corrupt data as there could still be some 2PC transactions to track, with RecentXmin moving backwards on successive calls to GetSnapshotData() in the same transaction. As SharedRecoveryState is the point to take into account to know if it is safe to discard KnownAssignedXids, this commit moves step 2) after step 3), so as we can never finish with empty snapshots. This exists since the introduction of hot standby, so backpatch all the way down. The window with incorrect snapshots is extremely small, but I have seen it when running 023_pitr_prepared_xact.pl, as did buildfarm member fairywren. Thomas Munro also found it independently. Special thanks to Andres Freund for taking the time to analyze this issue. Reported-by: Thomas Munro, Michael Paquier Analyzed-by: Andres Freund Discussion: https://postgr.es/m/20210422203603.fdnh3fu2mmfp2iov@alap3.anarazel.de Backpatch-through: 9.6
* Remove unstable, unnecessary test; fix typoAlvaro Herrera2021-10-01
| | | | | | | | | | | | | Commit ff9f111bce24 added some test code that's unportable and doesn't add meaningful coverage. Remove it rather than try and get it to work everywhere. While at it, fix a typo in a log message added by the aforementioned commit. Backpatch to 14. Discussion: https://postgr.es/m/3000074.1632947632@sss.pgh.pa.us
* Fix Portal snapshot tracking to handle subtransactions properly.Tom Lane2021-10-01
| | | | | | | | | | | | | | | | | | | | | | | Commit 84f5c2908 forgot to consider the possibility that EnsurePortalSnapshotExists could run inside a subtransaction with lifespan shorter than the Portal's. In that case, the new active snapshot would be popped at the end of the subtransaction, leaving a dangling pointer in the Portal, with mayhem ensuing. To fix, make sure the ActiveSnapshot stack entry is marked with the same subtransaction nesting level as the associated Portal. It's certainly safe to do so since we won't be here at all unless the stack is empty; hence we can't create an out-of-order stack. Let's also apply this logic in the case where PortalRunUtility sets portalSnapshot, just to be sure that path can't cause similar problems. It's slightly less clear that that path can't create an out-of-order stack, so add an assertion guarding it. Report and patch by Bertrand Drouvot (with kibitzing by me). Back-patch to v11, like the previous commit. Discussion: https://postgr.es/m/ff82b8c5-77f4-3fe7-6028-fcf3303e82dd@amazon.com
* Fix WAL replay in presence of an incomplete recordAlvaro Herrera2021-09-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Physical replication always ships WAL segment files to replicas once they are complete. This is a problem if one WAL record is split across a segment boundary and the primary server crashes before writing down the segment with the next portion of the WAL record: WAL writing after crash recovery would happily resume at the point where the broken record started, overwriting that record ... but any standby or backup may have already received a copy of that segment, and they are not rewinding. This causes standbys to stop following the primary after the latter crashes: LOG: invalid contrecord length 7262 at A8/D9FFFBC8 because the standby is still trying to read the continuation record (contrecord) for the original long WAL record, but it is not there and it will never be. A workaround is to stop the replica, delete the WAL file, and restart it -- at which point a fresh copy is brought over from the primary. But that's pretty labor intensive, and I bet many users would just give up and re-clone the standby instead. A fix for this problem was already attempted in commit 515e3d84a0b5, but it only addressed the case for the scenario of WAL archiving, so streaming replication would still be a problem (as well as other things such as taking a filesystem-level backup while the server is down after having crashed), and it had performance scalability problems too; so it had to be reverted. This commit fixes the problem using an approach suggested by Andres Freund, whereby the initial portion(s) of the split-up WAL record are kept, and a special type of WAL record is written where the contrecord was lost, so that WAL replay in the replica knows to skip the broken parts. With this approach, we can continue to stream/archive segment files as soon as they are complete, and replay of the broken records will proceed across the crash point without a hitch. Because a new type of WAL record is added, users should be careful to upgrade standbys first, primaries later. Otherwise they risk the standby being unable to start if the primary happens to write such a record. A new TAP test that exercises this is added, but the portability of it is yet to be seen. This has been wrong since the introduction of physical replication, so backpatch all the way back. In stable branches, keep the new XLogReaderState members at the end of the struct, to avoid an ABI break. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Nathan Bossart <bossartn@amazon.com> Discussion: https://postgr.es/m/202108232252.dh7uxf6oxwcy@alvherre.pgsql
* Document XLOG_INCLUDE_XID a little betterAlvaro Herrera2021-09-21
| | | | | | | | | | | | I noticed that commit 0bead9af484c left this flag undocumented in XLogSetRecordFlags, which led me to discover that the flag doesn't actually do what the one comment on it said it does. Improve the situation by adding some more comments. Backpatch to 14, where the aforementioned commit appears. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/202109212119.c3nhfp64t2ql@alvherre.pgsql
* Send NOTIFY signals during CommitTransaction.Tom Lane2021-09-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Formerly, we sent signals for outgoing NOTIFY messages within ProcessCompletedNotifies, which was also responsible for sending relevant ones of those messages to our connected client. It therefore had to run during the main-loop processing that occurs just before going idle. This arrangement had two big disadvantages: * Now that procedures allow intra-command COMMITs, it would be useful to send NOTIFYs to other sessions immediately at COMMIT (though, for reasons of wire-protocol stability, we still shouldn't forward them to our client until end of command). * Background processes such as replication workers would not send NOTIFYs at all, since they never execute the client communication loop. We've had requests to allow triggers running in replication workers to send NOTIFYs, so that's a problem. To fix these things, move transmission of outgoing NOTIFY signals into AtCommit_Notify, where it will happen during CommitTransaction. Also move the possible call of asyncQueueAdvanceTail there, to ensure we don't bloat the async SLRU if a background worker sends many NOTIFYs with no one listening. We can also drop the call of asyncQueueReadAllNotifications, allowing ProcessCompletedNotifies to go away entirely. That's because commit 790026972 added a call of ProcessNotifyInterrupt adjacent to PostgresMain's call of ProcessCompletedNotifies, and that does its own call of asyncQueueReadAllNotifications, meaning that we were uselessly doing two such calls (inside two separate transactions) whenever inbound notify signals coincided with an outbound notify. We need only set notifyInterruptPending to ensure that ProcessNotifyInterrupt runs, and we're done. The existing documentation suggests that custom background workers should call ProcessCompletedNotifies if they want to send NOTIFY messages. To avoid an ABI break in the back branches, reduce it to an empty routine rather than removing it entirely. Removal will occur in v15. Although the problems mentioned above have existed for awhile, I don't feel comfortable back-patching this any further than v13. There was quite a bit of churn in adjacent code between 12 and 13. At minimum we'd have to also backpatch 51004c717, and a good deal of other adjustment would also be needed, so the benefit-to-risk ratio doesn't look attractive. Per bug #15293 from Michael Powers (and similar gripes from others). Artur Zakirov and Tom Lane Discussion: https://postgr.es/m/153243441449.1404.2274116228506175596@wrigleys.postgresql.org
* Revert "Avoid creating archive status ".ready" files too early"Alvaro Herrera2021-09-04
| | | | | | | | | | This reverts commit 515e3d84a0b5 and equivalent commits in back branches. This solution to the problem has a number of problems, so we'll try again with a different approach. Per note from Andres Freund Discussion: https://postgr.es/m/20210831042949.52eqp5xwbxgrfank@alap3.anarazel.de
* Fix broken snapshot handling in parallel workers.Robert Haas2021-08-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | Pengchengliu reported an assertion failure in a parallel woker while performing a parallel scan using an overflowed snapshot. The proximate cause is that TransactionXmin was set to an incorrect value. The underlying cause is incorrect snapshot handling in parallel.c. In particular, InitializeParallelDSM() was unconditionally calling GetTransactionSnapshot(), because I (rhaas) mistakenly thought that was always retrieving an existing snapshot whereas, at isolation levels less than REPEATABLE READ, it's actually taking a new one. So instead do this only at higher isolation levels where there actually is a single snapshot for the whole transaction. By itself, this is not a sufficient fix, because we still need to guarantee that TransactionXmin gets set properly in the workers. The easiest way to do that seems to be to install the leader's active snapshot as the transaction snapshot if the leader did not serialize a transaction snapshot. This doesn't affect the results of future GetTrasnactionSnapshot() calls since those have to take a new snapshot anyway; what we care about is the side effect of setting TransactionXmin. Report by Pengchengliu. Patch by Greg Nancarrow, except for some comment text which I supplied. Discussion: https://postgr.es/m/002f01d748ac$eaa781a0$bff684e0$@tju.edu.cn
* Avoid creating archive status ".ready" files too earlyAlvaro Herrera2021-08-23
| | | | | | | | | | | | | | | | | | | | | | | WAL records may span multiple segments, but XLogWrite() does not wait for the entire record to be written out to disk before creating archive status files. Instead, as soon as the last WAL page of the segment is written, the archive status file is created, and the archiver may process it. If PostgreSQL crashes before it is able to write and flush the rest of the record (in the next WAL segment), the wrong version of the first segment file lingers in the archive, which causes operations such as point-in-time restores to fail. To fix this, keep track of records that span across segments and ensure that segments are only marked ready-for-archival once such records have been completely written to disk. This has always been wrong, so backpatch all the way back. Author: Nathan Bossart <bossartn@amazon.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Ryo Matsumura <matsumura.ryo@fujitsu.com> Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru> Discussion: https://postgr.es/m/CBDDFA01-6E40-46BB-9F98-9340F4379505@amazon.com
* Refresh apply delay on reload of recovery_min_apply_delay at recoveryMichael Paquier2021-08-16
| | | | | | | | | | | | | | | | | This commit ensures that the wait interval in the replay delay loop waiting for an amount of time defined by recovery_min_apply_delay is correctly handled on reload, recalculating the delay if this GUC value is updated, based on the timestamp of the commit record being replayed. The previous behavior would be problematic for example with replay still waiting even if the delay got reduced or just cancelled. If the apply delay was increased to a larger value, the wait would have just respected the old value set, finishing earlier. Author: Soumyadeep Chakraborty, Ashwin Agrawal Reviewed-by: Kyotaro Horiguchi, Michael Paquier Discussion: https://postgr.es/m/CAE-ML+93zfr-HLN8OuxF0BjpWJ17O5dv1eMvSE5jsj9jpnAXZA@mail.gmail.com Backpatch-through: 9.6
* Avoid unnecessary shared invalidations in ROLLBACK PREPAREDMichael Paquier2021-08-12
| | | | | | | | | | The performance gain is minimal, but this makes the logic more consistent with AtEOXact_Inval(). No other invalidation is needed in this case as PREPARE takes already care of sending any local ones. Author: Liu Huailing Reviewed-by: Tom Lane, Michael Paquier Discussion: https://postgr.es/m/OSZPR01MB6215AA84D71EF2B3D354CF86BE139@OSZPR01MB6215.jpnprd01.prod.outlook.com
* Remove some unnecessary casts in format argumentsPeter Eisentraut2021-08-08
| | | | | | We can use %zd or %zu directly, no need to cast to int. Conversely, some code was casting away from int when it could be using %d directly.
* Make parallel worker shutdown complete entirely via before_shmem_exit().Andres Freund2021-08-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a step toward storing stats in dynamic shared memory. As dynamic shared memory segments are detached from just after before_shmem_exit() callbacks are processed, but before on_shmem_exit() callbacks are, no stats can be collected after before_shmem_exit() callbacks have been processed. Parallel worker shutdown can cause stats to be emitted during DSM detach callbacks, e.g. for SharedFileSet (which closes its files, which can causes fd.c to emit stats about temporary files). Therefore parallel worker shutdown needs to complete during the processing of before_shmem_exit callbacks. One might think this problem could instead be solved by carefully ordering the attaching to DSM segments, so that the pgstats segments get detached from later than the parallel query ones. That turns out to not work because the stats hash might need to grow which can cause new segments to be allocated, which then will be detached from earlier. There are two code changes: First, call ParallelWorkerShutdown() via before_shmem_exit. That's a good idea on its own, because other shutdown callbacks like ShutdownPostgres and ShutdownAuxiliaryProcess are called via before_*. Second, explicitly detach from the parallel query DSM segment, thereby ensuring all stats are emitted during ParallelWorkerShutdown(). There are nicer solutions to these problems, but it's not obvious which of those solutions is the correct one. As the shared memory stats work already is a huge amount of work... Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de Discussion: https://postgr.es/m/20210803023612.iziacxk5syn2r4ut@alap3.anarazel.de