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path: root/src/backend/access/transam/xlog.c
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2023-06-20Enable archiving in recovery TAP test 009_twophase.plMichael Paquier
This is a follow-up of f663b00, that has been committed to v13 and v14, tweaking the TAP test for two-phase transactions so as it provides coverage for the bug that has been fixed. This change is done in its own commit for clarity, as v15 and HEAD did not show the problematic behavior, still missed coverage for it. While on it, this adds a comment about the dependency of the last partial segment rename and RecoverPreparedTransactions() at the end of recovery, as that can be easy to miss. Author: Michael Paquier Reviewed-by: Kyotaro Horiguchi Discussion: https://postgr.es/m/743b9b45a2d4013bd90b6a5cba8d6faeb717ee34.camel@cybertec.at Backpatch-through: 13
2023-04-27Prevent underflow in KeepLogSeg().Nathan Bossart
The call to XLogGetReplicationSlotMinimumLSN() might return a greater LSN than the one given to the function. Subsequent segment number calculations might then underflow, which could result in unexpected behavior when removing or recyling WAL files. This was introduced with max_slot_wal_keep_size in c655077639. To fix, skip the block of code for replication slots if the LSN is greater. Reported-by: Xu Xingwang Author: Kyotaro Horiguchi Reviewed-by: Junwang Zhao Discussion: https://postgr.es/m/17903-4288d439dee856c6%40postgresql.org Backpatch-through: 13
2022-09-22Clear ps display of startup process at the end of recoveryMichael Paquier
If the ps display is not cleared at this point, the process could continue displaying "recovering NNN" even if handling end-of-recovery steps. df9274a has tackled that by providing some information with the end-of-recovery checkpoint but 7ff23c6 has nullified the effect of the first commit. Per a suggestion from Justin, just clear the ps display when we are done with recovery, so as no incorrect information is displayed. This may get extended in the future, but for now restore the pre-7ff23c6 behavior. Author: Justin Prysby Discussion: https://postgr.es/m/20220913223954.GU31833@telsasoft.com Backpatch-through: 15
2022-09-20Suppress variable-set-but-not-used warnings from clang 15.Tom Lane
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
2022-08-29Prevent WAL corruption after a standby promotion.Robert Haas
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
2022-08-10Move basebackup code to new directory src/backend/backupRobert Haas
Reviewed by David Steele and Justin Pryzby Discussion: http://postgr.es/m/CA+TgmoafqboATDSoXHz8VLrSwK_MDhjthK4hEpYjqf9_1Fmczw%40mail.gmail.com
2022-07-22Remove unnecessary Windows-specific basebackup code.Thomas Munro
Commit c6f2f016 added an explicit check for a Windows "junction point". That turned out to be needed only because get_dirent_type() was busted on Windows. It's been fixed by commit 9d3444dc, so remove it. Add a TAP-test to demonstrate that in-place tablespaces are copied by pg_basebackup. This exercises the codepath that would fail before c6f2f016 on Windows, and shows that it still doesn't fail now that we're using get_dirent_type() on both Windows and Unix. Back-patch to 15, where in-place tablespaces arrived and caused this problem (ie directories where previously only symlinks were expected). Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGLzLK4PUPx0_AwXEWXOYAejU%3D7XpxnYE55Y%2Be7hB2N3FA%40mail.gmail.com
2022-07-20Fix assertion failure and segmentation fault in backup code.Fujii Masao
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
2022-06-08Be more careful about GucSource for internally-driven GUC settings.Tom Lane
The original advice for hard-wired SetConfigOption calls was to use PGC_S_OVERRIDE, particularly for PGC_INTERNAL GUCs. However, that's really overkill for PGC_INTERNAL GUCs, since there is no possibility that we need to override a user-provided setting. Instead use PGC_S_DYNAMIC_DEFAULT in most places, so that the value will appear with source = 'default' in pg_settings and thereby not be shown by psql's new \dconfig command. The one exception is that when changing in_hot_standby in a hot-standby session, we still use PGC_S_OVERRIDE, because people felt that seeing that in \dconfig would be a good thing. Similarly use PGC_S_DYNAMIC_DEFAULT for the auto-tune value of wal_buffers (if possible, that is if wal_buffers wasn't explicitly set to -1), and for the typical 2MB value of max_stack_depth. In combination these changes remove four not-very-interesting entries from the typical output of \dconfig, all of which people fingered as "why is that showing up?" in the discussion thread. Discussion: https://postgr.es/m/3118455.1649267333@sss.pgh.pa.us
2022-05-12Pre-beta mechanical code beautification.Tom Lane
Run pgindent, pgperltidy, and reformat-dat-files. I manually fixed a couple of comments that pgindent uglified.
2022-05-09Fix control file update done in restartpoints still running after promotionMichael Paquier
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(). This problem exists in all the stable branches. However, commit 7ff23c6, by removing the last call of CreateCheckPoint() from the startup process, has made this bug much easier to reason about as concurrent checkpoints are not possible anymore. No backpatch is done yet, mostly out of caution from me as a point release is close by, but we need to think harder about the case of concurrent checkpoints at promotion if the bgwriter is not considered as running by the startup process in ~v14, so this change is done only on HEAD for the moment. 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
2022-04-28Revert recent changes with durable_rename_excl()Michael Paquier
This reverts commits 2c902bb and ccfbd92. Per buildfarm members kestrel, rorqual and calliphoridae, the assertions checking that a TLI history file should not exist when created by a WAL receiver have been failing, and switching to durable_rename() over durable_rename_excl() would cause the newest TLI history file to overwrite the existing one. We need to think harder about such cases, so revert the new logic for now. Note that all the failures have been reported in the test 025_stuck_on_old_timeline. Discussion: https://postgr.es/m/511362.1651116498@sss.pgh.pa.us
2022-04-28Replace existing durable_rename_excl() calls with durable_rename()Michael Paquier
durable_rename_excl() attempts to avoid overwriting any existing files by using link() and unlink(), falling back to rename() on some platforms (e.g., Windows where link() followed by unlink() is not concurrent-safe, see 909b449). Most callers of durable_rename_excl() use it just in case there is an existing file, but it happens that for all of them we never expect a target file to exist (WAL segment recycling, creation of timeline history file and basic_archive). basic_archive used durable_rename_excl() to avoid overwriting an archive concurrently created by another server. Now, there is a stat() call to avoid overwriting an existing archive a couple of lines above, so note that this change opens a small TOCTOU window in this module between the stat() call and durable_rename(). Furthermore, as mentioned in the top comment of durable_rename_excl(), this routine can result in multiple hard links to the same file and data corruption, with two or more links to the same file in pg_wal/ if a crash happens before the unlink() call during WAL recycling. Specifically, this would produce links to the same file for the current WAL file and the next one because the half-recycled WAL file was re-recycled during crash recovery of a follow-up cluster restart. This change replaces all calls to durable_rename_excl() with durable_rename(). This removes the protection against accidentally overwriting an existing file, but some platforms are already living without it, and all those code paths never expect an existing file (a couple of assertions are added to check after that, in case). This is a bug fix, but knowing the unlikeliness of the problem involving one of more crashes at an exceptionally bad moment, no backpatch is done. This could be revisited in the future. Author: Nathan Bossart Reviewed-by: Robert Haas, Kyotaro Horiguchi, Michael Paquier Discussion: https://postgr.es/m/20220407182954.GA1231544@nathanxps13
2022-04-21Rethink method for assigning OIDs to the template0 and postgres DBs.Tom Lane
Commit aa0105141 assigned fixed OIDs to template0 and postgres in a very ad-hoc way. Notably, instead of teaching Catalog.pm about these OIDs, the unused_oids script was just hacked to not show them as unused. That's problematic since, for example, duplicate_oids wouldn't report any future conflict. Hence, invent a macro DECLARE_OID_DEFINING_MACRO() that can be used to define an OID that is known to Catalog.pm and will participate in duplicate-detection as well as renumbering by renumber_oids.pl. (We don't anticipate renumbering these particular OIDs, but we might as well build out all the Catalog.pm infrastructure while we're here.) Another issue is that aa0105141 neglected to touch IsPinnedObject, with the result that it now claimed template0 and postgres are pinned. The right thing to do there seems to be to teach it that no database is pinned, since in fact DROP DATABASE doesn't check for pinned-ness (and at least for these cases, that is an intentional choice). It's not clear whether this wrong answer had any visible effect, but perhaps it could have resulted in erroneous management of dependency entries. In passing, rename the TemplateDbOid macro to Template1DbOid to reduce confusion (likely we should have done that way back when we invented template0, but we didn't), and rename the OID macros for template0 and postgres to have a similar style. There are no changes to postgres.bki here, so no need for a catversion bump. Discussion: https://postgr.es/m/2935358.1650479692@sss.pgh.pa.us
2022-04-11Remove dead code in do_pg_backup_start().Tom Lane
As of commit 39969e2a1, no caller of do_pg_backup_start() passes NULL for labelfile or tblspcmapfile, nor is it plausible that any would do so in the future. Remove the code that coped with that case, as (a) it's dead and (b) it causes Coverity to bleat about possibly leaked storage. While here, do some janitorial work on the function's header comment.
2022-04-08Rename delayChkpt to delayChkptFlags.Robert Haas
Before commit 412ad7a55639516f284cd0ef9757d6ae5c7abd43, delayChkpt was a Boolean. Now it's an integer. Extensions using it need to be appropriately updated, so let's rename the field to make sure that a hard compilation failure occurs. Replacing delayChkpt with delayChkptFlags made a few comments extend past 80 characters, so I reflowed them and changed some wording very slightly. The back-branches will need a different change to restore compatibility with existing minor releases; this is just for master. Per suggestion from Tom Lane. Discussion: http://postgr.es/m/a7880f4d-1d74-582a-ada7-dad168d046d1@enterprisedb.com
2022-04-07Prefetch data referenced by the WAL, take II.Thomas Munro
Introduce a new GUC recovery_prefetch. When enabled, look ahead in the WAL and try to initiate asynchronous reading of referenced data blocks that are not yet cached in our buffer pool. For now, this is done with posix_fadvise(), which has several caveats. Since not all OSes have that system call, "try" is provided so that it can be enabled where available. Better mechanisms for asynchronous I/O are possible in later work. Set to "try" for now for test coverage. Default setting to be finalized before release. The GUC wal_decode_buffer_size limits the distance we can look ahead in bytes of decoded data. The existing GUC maintenance_io_concurrency is used to limit the number of concurrent I/Os allowed, based on pessimistic heuristics used to infer that I/Os have begun and completed. We'll also not look more than maintenance_io_concurrency * 4 block references ahead. Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (earlier version) Reviewed-by: Andres Freund <andres@anarazel.de> (earlier version) Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> (earlier version) Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (earlier version) Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com> (earlier version) Tested-by: Dmitry Dolgov <9erthalion6@gmail.com> (earlier version) Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com> (earlier version) Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
2022-04-06pgstat: store statistics in shared memory.Andres Freund
Previously the statistics collector received statistics updates via UDP and shared statistics data by writing them out to temporary files regularly. These files can reach tens of megabytes and are written out up to twice a second. This has repeatedly prevented us from adding additional useful statistics. Now statistics are stored in shared memory. Statistics for variable-numbered objects are stored in a dshash hashtable (backed by dynamic shared memory). Fixed-numbered stats are stored in plain shared memory. The header for pgstat.c contains an overview of the architecture. The stats collector is not needed anymore, remove it. By utilizing the transactional statistics drop infrastructure introduced in a prior commit statistics entries cannot "leak" anymore. Previously leaked statistics were dropped by pgstat_vacuum_stat(), called from [auto-]vacuum. On systems with many small relations pgstat_vacuum_stat() could be quite expensive. Now that replicas drop statistics entries for dropped objects, it is not necessary anymore to reset stats when starting from a cleanly shut down replica. Subsequent commits will perform some further code cleanup, adapt docs and add tests. Bumps PGSTAT_FILE_FORMAT_ID. Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Author: Andres Freund <andres@anarazel.de> Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-By: Andres Freund <andres@anarazel.de> Reviewed-By: Thomas Munro <thomas.munro@gmail.com> Reviewed-By: Justin Pryzby <pryzby@telsasoft.com> Reviewed-By: "David G. Johnston" <david.g.johnston@gmail.com> Reviewed-By: Tomas Vondra <tomas.vondra@2ndquadrant.com> (in a much earlier version) Reviewed-By: Arthur Zakirov <a.zakirov@postgrespro.ru> (in a much earlier version) Reviewed-By: Antonin Houska <ah@cybertec.at> (in a much earlier version) Discussion: https://postgr.es/m/20220303021600.hs34ghqcw6zcokdh@alap3.anarazel.de Discussion: https://postgr.es/m/20220308205351.2xcn6k4x5yivcxyd@alap3.anarazel.de Discussion: https://postgr.es/m/20210319235115.y3wz7hpnnrshdyv6@alap3.anarazel.de
2022-04-06Remove exclusive backup modeStephen Frost
Exclusive-mode backups have been deprecated since 9.6 (when non-exclusive backups were introduced) due to the issues they can cause should the system crash while one is running and generally because non-exclusive provides a much better interface. Further, exclusive backup mode wasn't really being tested (nor was most of the related code- like being able to log in just to stop an exclusive backup and the bits of the state machine related to that) and having to possibly deal with an exclusive backup and the backup_label file existing during pg_basebackup, pg_rewind, etc, added other complexities that we are better off without. This patch removes the exclusive backup mode, the various special cases for dealing with it, and greatly simplifies the online backup code and documentation. Authors: David Steele, Nathan Bossart Reviewed-by: Chapman Flack Discussion: https://postgr.es/m/ac7339ca-3718-3c93-929f-99e725d1172c@pgmasters.net https://postgr.es/m/CAHg+QDfiM+WU61tF6=nPZocMZvHDzCK47Kneyb0ZRULYzV5sKQ@mail.gmail.com
2022-03-24Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.Robert Haas
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
2022-03-18Add circular WAL decoding buffer, take II.Thomas Munro
Teach xlogreader.c to decode the WAL into a circular buffer. This will support optimizations based on looking ahead, to follow in a later commit. * XLogReadRecord() works as before, decoding records one by one, and allowing them to be examined via the traditional XLogRecGetXXX() macros and certain traditional members like xlogreader->ReadRecPtr. * An alternative new interface XLogReadAhead()/XLogNextRecord() is added that returns pointers to DecodedXLogRecord objects so that it's now possible to look ahead in the WAL stream while replaying. * In order to be able to use the new interface effectively while streaming data, support is added for the page_read() callback to respond to a new nonblocking mode with XLREAD_WOULDBLOCK instead of waiting for more data to arrive. No direct user of the new interface is included in this commit, though XLogReadRecord() uses it internally. Existing code doesn't need to change, except in a few places where it was accessing reader internals directly and now needs to go through accessor macros. Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions) Discussion: https://postgr.es/m/CA+hUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq=AovOddfHpA@mail.gmail.com
2022-03-16Fix race between DROP TABLESPACE and checkpointing.Thomas Munro
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
2022-03-15Fix collection of typos in the code and the documentationMichael Paquier
Some words were duplicated while other places were grammatically incorrect, including one variable name in the code. Author: Otto Kekalainen, Justin Pryzby Discussion: https://postgr.es/m/7DDBEFC5-09B6-4325-B942-B563D1A24BDC@amazon.com
2022-03-15Fix pg_basebackup with in-place tablespaces.Thomas Munro
Previously, pg_basebackup from a cluster that contained an 'in-place' tablespace, as introduced by commit 7170f215, would produce a harmless warning on Unix and fail completely on Windows. Reported-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/20220304.165449.1200020258723305904.horikyota.ntt%40gmail.com
2022-02-20Fix uninitialized variable.Heikki Linnakangas
I'm very surprised the compiler didn't warn about it. But Coverity and Valgrind did.
2022-02-16Fix read beyond buffer bug introduced by the split xlog.c patch.Heikki Linnakangas
FinishWalRecovery() copied the valid part of the last WAL block into a palloc'd buffer, and the code in StartupXLOG() copied it to the WAL buffer. But the memcpy in StartupXLOG() copied a full 8kB block, not just the valid part, i.e. it copied from beyond the end of the buffer. The invalid part was cleared immediately afterwards, so as long as the memory was allocated and didn't segfault, it didn't do any harm, but it can definitely segfault. Discussion: https://www.postgresql.org/message-id/efc12e32-5af2-3485-5b1d-5af9f707491a@iki.fi
2022-02-16Split xlog.c into xlog.c and xlogrecovery.c.Heikki Linnakangas
This moves the functions related to performing WAL recovery into the new xlogrecovery.c source file, leaving xlog.c responsible for maintaining the WAL buffers, coordinating the startup and switch from recovery to normal operations, and other miscellaneous stuff that have always been in xlog.c. Reviewed-by: Andres Freund, Kyotaro Horiguchi, Robert Haas Discussion: https://www.postgresql.org/message-id/a31f27b4-a31d-f976-6217-2b03be646ffa%40iki.fi
2022-02-16Move code around in StartupXLOG().Heikki Linnakangas
This is in preparation for the next commit, which will split off recovery-related code from xlog.c into a new source file. This is the order that things will happen with the next commit, and the point of this commit is to make these ordering changes more explicit, while the next commit mechanically moves the source code to the new file. To aid review, I added "BEGIN/END function" comments to mark which blocks of code are moved to which functions in the next commit. They will be gone in the next commit. Reviewed-by: Andres Freund, Kyotaro Horiguchi, Robert Haas Discussion: https://www.postgresql.org/message-id/a31f27b4-a31d-f976-6217-2b03be646ffa%40iki.fi
2022-02-16Refactor setting XLP_FIRST_IS_OVERWRITE_CONTRECORD.Heikki Linnakangas
Set it directly in CreateOverwriteContrecordRecord(). That way, AdvanceXLInsertBuffer() doesn't need the missingContrecPtr global variable. This is in preparation for splitting xlog.c into multiple files. Reviewed-by: Robert Haas Discussion: https://www.postgresql.org/message-id/a462d79c-cb5a-47cc-e9ac-616b5003965f%40iki.fi
2022-02-16Run pgindent on xlog.c.Heikki Linnakangas
To tidy up after some recent refactorings in xlog.c. These would be fixed by the pgindent run we do at the end of the development cycle, but I want to clean these up now as I'm about to do some more big refactorings on xlog.c.
2022-02-03Allow archiving via loadable modules.Robert Haas
Running a shell command for each file to be archived has a lot of overhead and may not offer as much error checking as you want, or the exact semantics that you want. So, offer the option to call a loadable module for each file to be archived, rather than running a shell command. Also, add a 'basic_archive' contrib module as an example implementation that archives to a local directory. Nathan Bossart, with a little bit of kibitzing by me. Discussion: http://postgr.es/m/20220202224433.GA1036711@nathanxps13
2022-01-25Improve errors related to incorrect TLI on checkpoint record replayMichael Paquier
WAL replay would cause a hard crash if the timeline expected by a XLOG_END_OF_RECOVERY, a XLOG_CHECKPOINT_ONLINE, or a XLOG_CHECKPOINT_SHUTDOWN record is not the same as the timeline being replayed, using the same error message for all three of them. This commit changes those error messages to use different wordings, adapted to each record type, which is useful when it comes to the debugging of an issue in this area. Author: Amul Sul Reviewed-by: Nathan Bossart, Robert Haas Discussion: https://postgr.es/m/CAAJ_b97i1ZerYC_xW6o_AiDSW5n+sGi8k91Yc8KS8bKWKxjqwQ@mail.gmail.com
2022-01-25Fix various typos, grammar and code style in comments and docsMichael Paquier
This fixes a set of issues that have accumulated over the past months (or years) in various code areas. Most fixes are related to some recent additions, as of the development of v15. Author: Justin Pryzby Discussion: https://postgr.es/m/20220124030001.GQ23027@telsasoft.com
2022-01-07Update copyright for 2022Bruce Momjian
Backpatch-through: 10
2021-12-29Fix incorrect format placeholdersPeter Eisentraut
2021-12-16Change ProcSendSignal() to take pgprocno.Thomas Munro
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>
2021-12-13Remove InitXLOGAccess().Robert Haas
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
2021-12-13Default to log_checkpoints=on, log_autovacuum_min_duration=10mRobert Haas
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
2021-12-01Remove mention of TimeLineID update from commentsDaniel Gustafsson
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
2021-11-29Centralize timestamp computation of control file on updatesMichael Paquier
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
2021-11-24Replace straggling uses of ReadRecPtr/EndRecPtr.Andres Freund
d2ddfa681db removed ReadRecPtr/EndRecPtr, but two uses within an #ifdef WAL_DEBUG escaped. Discussion: https://postgr.es/m/20211124231206.gbadj5bblcljb6d5@alap3.anarazel.de
2021-11-24xlog.c: Remove global variables ReadRecPtr and EndRecPtr.Robert Haas
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
2021-11-24Fix corner-case failure to detect improper timeline switch.Robert Haas
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
2021-11-22Be more specific about OOM in XLogReaderAllocateAlvaro Herrera
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
2021-11-22Report wait events for local shell commands like archive_command.Fujii Masao
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
2021-11-17Remove global variable "LastRec" in xlog.cMichael Paquier
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
2021-11-16Move InitXLogInsert() call from InitXLOGAccess() to BaseInit().Robert Haas
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
2021-11-10More cleanup of 'ThisTimeLineID'.Robert Haas
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
2021-11-07Silence uninitialized-variable warning.Tom Lane
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
2021-11-05Change ThisTimeLineID from a global variable to a local variable.Robert Haas
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