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* Message wording improvementsPeter Eisentraut2023-07-10
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* Document relaxed HOT for summarizing indexesTomas Vondra2023-07-07
| | | | | | | | | | | | | Commit 19d8e2308b allowed a weaker check for HOT with summarizing indexes, but it did not update README.HOT. So do that now. Patch by Matthias van de Meent, minor changes by me. Backpatch to 16, where the optimization was introduced. Author: Matthias van de Meent Reviewed-by: Tomas Vondra Backpatch-through: 16 Discussion: https://postgr.es/m/CAEze2WiEOm8V+c9kUeYp2BPhbEc5s473fUf51xNeqvSFGv44Ew@mail.gmail.com
* Fix race in SSI interaction with gin fast path.Thomas Munro2023-07-04
| | | | | | | | | | | | | | | | | | The ginfast.c code previously checked for conflicts in before locking the relevant buffer, leaving a window where a RW conflict could be missed. Re-order. There was also a place where buffer ID and block number were confused while trying to predicate-lock a page, noted by visual inspection. Back-patch to all supported releases. Fixes one more problem discovered with the reproducer from bug #17949, in this case when Dmitry tried other index types. Reported-by: Artem Anisimov <artem.anisimov.255@gmail.com> Reported-by: Dmitry Dolgov <9erthalion6@gmail.com> Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Discussion: https://postgr.es/m/17949-a0f17035294a55e2%40postgresql.org
* Fix race in SSI interaction with bitmap heap scan.Thomas Munro2023-07-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When performing a bitmap heap scan, we don't want to miss concurrent writes that occurred after we observed the heap's rs_nblocks, but before we took predicate locks on index pages. Therefore, we can't skip fetching any heap tuples that are referenced by the index, because we need to test them all with CheckForSerializableConflictOut(). The old optimization that would ignore any references to blocks >= rs_nblocks gets in the way of that requirement, because it means that concurrent writes in that window are ignored. Removing that optimization shouldn't affect correctness at any isolation level, because any new tuples shouldn't be visible to an MVCC snapshot. There also shouldn't be any error-causing references to heap blocks past the end, because we should have held at least an AccessShareLock on the table before the index scan. It can't get smaller while our transaction is running. For now, though, we'll keep the optimization at lower levels to avoid making unnecessary changes in a bug fix. Back-patch to all supported releases. In release 11, the code is in a different place but not fundamentally different. Fixes one aspect of bug #17949. Reported-by: Artem Anisimov <artem.anisimov.255@gmail.com> Reviewed-by: Dmitry Dolgov <9erthalion6@gmail.com> Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Discussion: https://postgr.es/m/17949-a0f17035294a55e2%40postgresql.org
* Fix race in SSI interaction with empty btrees.Thomas Munro2023-07-04
| | | | | | | | | | | | | | | | | When predicate-locking btrees, we have a special case for completely empty btrees, since there is no page to lock. This was racy, because, without buffer lock held, a matching key could be inserted between the _bt_search() and the PredicateLockRelation() calls. Fix, by rechecking _bt_search() after taking the relation-level SIREAD lock, if using SERIALIZABLE isolation and an empty btree is discovered. Back-patch to all supported releases. Fixes one aspect of bug #17949. Reported-by: Artem Anisimov <artem.anisimov.255@gmail.com> Reviewed-by: Dmitry Dolgov <9erthalion6@gmail.com> Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Discussion: https://postgr.es/m/17949-a0f17035294a55e2%40postgresql.org
* Silence "missing contrecord" error.Thomas Munro2023-07-03
| | | | | | | | | | | | | | | | | Commit dd38ff28ad added a new error message "missing contrecord" when we fail to reassemble a record. Unfortunately that caused noisy messages to be logged by pg_waldump at end of segment, and by walsender when asked to shut down on a segment boundary. Remove the new error message, so that this condition signals end-of- WAL without a message. It's arguably a reportable condition that should not be silenced while performing crash recovery, but fixing that without introducing noise in the other cases will require more research. Back-patch to 15. Reported-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Discussion: https://postgr.es/m/6a1df56e-4656-b3ce-4b7a-a9cb41df8189%40enterprisedb.com
* nbtree VACUUM: cope with topparent inconsistencies.Peter Geoghegan2023-06-21
| | | | | | | | | | | | | | | | | | Avoid "right sibling %u of block %u is not next child" errors when vacuuming a corrupt nbtree index. Just LOG the issue and press on. That way VACUUM will have a decent chance of finishing off all required processing for the index (and for the table as a whole). This is similar to recent work from commit 5abff197, as well as work from commit 5b861baa (later backpatched as commit 43e409ce), which taught nbtree VACUUM to keep going when its "re-find" check fails. The hardening added by this commit takes place directly after the "re-find" check, right before the critical section for the first stage of page deletion. Author: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-Wz=dayg0vjs4+er84TS9ami=csdzjpuiCGbEw=idhwqhzQ@mail.gmail.com Backpatch: 11- (all supported versions).
* Enable archiving in recovery TAP test 009_twophase.plMichael Paquier2023-06-20
| | | | | | | | | | | | | | | | | 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
* nbtree: Allocate new pages in separate function.Peter Geoghegan2023-06-10
| | | | | | | | | | | | | | | | | | | | | | | | Split nbtree's _bt_getbuf function is two: code that read locks or write locks existing pages remains in _bt_getbuf, while code that deals with allocating new pages is moved to a new, dedicated function called _bt_allocbuf. This simplifies most _bt_getbuf callers, since it is no longer necessary for them to pass a heaprel argument. Many of the changes to nbtree from commit 61b313e4 can be reverted. This minimizes the divergence between HEAD/PostgreSQL 16 and earlier release branches. _bt_allocbuf replaces the previous nbtree idiom of passing P_NEW to _bt_getbuf. There are only 3 affected call sites, all of which continue to pass a heaprel for recovery conflict purposes. Note that nbtree's use of P_NEW was superficial; nbtree never actually relied on the P_NEW code paths in bufmgr.c, so this change is strictly mechanical. GiST already took the same approach; it has a dedicated function for allocating new pages called gistNewBuffer(). That factor allowed commit 61b313e4 to make much more targeted changes to GiST. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi> Discussion: https://postgr.es/m/CAH2-Wz=8Z9qY58bjm_7TAHgtW6RzZ5Ke62q5emdCEy9BAzwhmg@mail.gmail.com
* Revert "Fix search_path to a safe value during maintenance operations."Jeff Davis2023-06-10
| | | | This reverts commit 05e17373517114167d002494e004fa0aa32d1fd1.
* Fix search_path to a safe value during maintenance operations.Jeff Davis2023-06-09
| | | | | | | | | | | | | | | | | | | While executing maintenance operations (ANALYZE, CLUSTER, REFRESH MATERIALIZED VIEW, REINDEX, or VACUUM), set search_path to 'pg_catalog, pg_temp' to prevent inconsistent behavior. Functions that are used for functional indexes, in index expressions, or in materialized views and depend on a different search path must be declared with CREATE FUNCTION ... SET search_path='...'. This change addresses a security risk introduced in commit 60684dd834, where a role with MAINTAIN privileges on a table may be able to escalate privileges to the table owner. That commit is not yet part of any release, so no need to backpatch. Discussion: https://postgr.es/m/e44327179e5c9015c8dda67351c04da552066017.camel%40j-davis.com Reviewed-by: Greg Stark Reviewed-by: Nathan Bossart
* Fix missing word in nbtree/README.Nathan Bossart2023-06-08
| | | | | | | Reported-by: Daniel Westermann Author: Gurjeet Singh Reviewed-by: Richard Guo Discussion: https://postgr.es/m/ZR0P278MB0427F0E0CE4ED140F52D1923D250A%40ZR0P278MB0427.CHEP278.PROD.OUTLOOK.COM
* Initialize 'recordXtime' to silence compiler warning.Heikki Linnakangas2023-06-06
| | | | | | | | | | In reality, recordXtime will always be set by the getRecordTimestamp call, but the compiler doesn't necessarily see that. Back-patch to all supported versions. Author: Tristan Partin Discussion: https://www.postgresql.org/message-id/CT5MN8E11U0M.1NYNCHXYUHY41@gonk
* nbtree VACUUM: cope with right sibling link corruption.Peter Geoghegan2023-05-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid "right sibling's left-link doesn't match" errors when vacuuming a corrupt nbtree index. Just LOG the issue and press on. That way VACUUM will have a decent chance of finishing off all required processing for the index (and for the table as a whole). This error was seen in the field from time to time (it's more than a theoretical risk), so giving VACUUM the ability to press on like this has real value. Nothing short of a REINDEX is expected to fix the underlying index corruption, so giving up (by throwing an error) risks making a bad situation far worse. Anything that blocks forward progress by VACUUM like this might go unnoticed for a long time. This could eventually lead to a wraparound/xidStopLimit outage. Note that _bt_unlink_halfdead_page() has always been able to bail on page deletion when the target page's left sibling page was in an inconsistent state. It now does the same thing (returns false to back out of the second phase of deletion) when it notices sibling link corruption in the target page's right sibling page. This is similar to the work from commit 5b861baa (later backpatched as commit 43e409ce), which taught nbtree to press on with vacuuming an index when page deletion fails to "re-find" a downlink in the target page's parent page. The "re-find" check seems to make VACUUM bail on page deletion more often in practice, but there is no reason to take any chances here. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi> Discussion: https://postgr.es/m/CAH2-Wzko2q2kP1+UvgJyP9g0mF4hopK0NtQZcxwvMv9_ytGhkQ@mail.gmail.com Backpatch: 11- (all supported versions).
* Pre-beta mechanical code beautification.Tom Lane2023-05-19
| | | | | | | | | | | | | | | Run pgindent, pgperltidy, and reformat-dat-files. This set of diffs is a bit larger than typical. We've updated to pg_bsd_indent 2.1.2, which properly indents variable declarations that have multi-line initialization expressions (the continuation lines are now indented one tab stop). We've also updated to perltidy version 20230309 and changed some of its settings, which reduces its desire to add whitespace to lines to make assignments etc. line up. Going forward, that should make for fewer random-seeming changes to existing code. Discussion: https://postgr.es/m/20230428092545.qfb3y5wcu4cm75ur@alvherre.pgsql
* Message style improvementsPeter Eisentraut2023-05-19
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* Fix handling of empty ranges and NULLs in BRINTomas Vondra2023-05-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRIN indexes did not properly distinguish between summaries for empty (no rows) and all-NULL ranges, treating them as essentially the same thing. Summaries were initialized with allnulls=true, and opclasses simply reset allnulls to false when processing the first non-NULL value. This however produces incorrect results if the range starts with a NULL value (or a sequence of NULL values), in which case we forget the range contains NULL values when adding the first non-NULL value. This happens because the allnulls flag is used for two separate purposes - to mark empty ranges (not representing any rows yet) and ranges containing only NULL values. Opclasses don't know which of these cases it is, and so don't know whether to set hasnulls=true. Setting the flag in both cases would make it correct, but it would also make BRIN indexes useless for queries with IS NULL clauses. All ranges start empty (and thus allnulls=true), so all ranges would end up with either allnulls=true or hasnulls=true. The severity of the issue is somewhat reduced by the fact that it only happens when adding values to an existing summary with allnulls=true. This can happen e.g. for small tables (because a summary for the first range exists for all BRIN indexes), or for tables with large fraction of NULL values in the indexed columns. Bulk summarization (e.g. during CREATE INDEX or automatic summarization) that processes all values at once is not affected by this issue. In this case the flags were updated in a slightly different way, not forgetting the NULL values. To identify empty ranges we use a new flag, stored in an unused bit in the BRIN tuple header so the on-disk format remains the same. A matching flag is added to BrinMemTuple, into a 3B gap after bt_placeholder. That means there's no risk of ABI breakage, although we don't actually pass the BrinMemTuple to any public API. We could also skip storing index tuples for empty summaries, but then we'd have to always process such ranges - even if there are no rows in large parts of the table (e.g. after a bulk DELETE), it would still require reading the pages etc. So we store them, but ignore them when building the bitmap. Backpatch to 11. The issue exists since BRIN indexes were introduced in 9.5, but older releases are already EOL. Backpatch-through: 11 Reviewed-by: Justin Pryzby, Matthias van de Meent, Alvaro Herrera Discussion: https://postgr.es/m/402430e4-7d9d-6cf1-09ef-464d80afff3b@enterprisedb.com
* Fix handling of NULLs when merging BRIN summariesTomas Vondra2023-05-18
| | | | | | | | | | | | | | | | | | | | | | When merging BRIN summaries, union_tuples() did not correctly update the target hasnulls/allnulls flags. When merging all-NULL summary into a summary without any NULL values, the result had both flags set to false (instead of having hasnulls=true). This happened because the code only considered the hasnulls flags, ignoring the possibility the source summary has allnulls=true. Discovered while investigating issues with handling empty BRIN ranges and handling of NULL values, but it's a separate problem (has nothing to do with empty ranges). Fixed by considering both flags on the source summary, and updating the hasnulls flag on the target summary. Backpatch to 11. The bug exists since 9.5 (where BRIN indexes were introduced), but those releases are EOL already. Discussion: https://postgr.es/m/9d993d0d-e431-2196-9ccc-0554d0e60154%40enterprisedb.com
* Fix typos in commentsMichael Paquier2023-05-02
| | | | | | | | | The changes done in this commit impact comments with no direct user-visible changes, with fixes for incorrect function, variable or structure names. Author: Alexander Lakhin Discussion: https://postgr.es/m/e8c38840-596a-83d6-bd8d-cebc51111572@gmail.com
* Fix assertion failure in heap_vacuum_relDaniel Gustafsson2023-04-28
| | | | | | | | | | | | | Commit 7d71d3dd08 changed resetting the VacuumFailsafeActive flag to an assertion since the flag is reset before starting vacuuming a relation. This however failed to take recursive calls of vacuum_rel() and vacuum of TOAST tables into consideration. Fix by reverting back to resettting the flag. Author: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Reported-by: John Naylor <john.naylor@enterprisedb.com> Discussion: https://postgr.es/m/CAFBsxsFz=GqaG5Ens5aNgVYoV2Y+pfMUijX0ku+CCkWfALwiqg@mail.gmail.com
* Prevent underflow in KeepLogSeg().Nathan Bossart2023-04-27
| | | | | | | | | | | | | | | 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
* Re-add tracking of wait event SLRUFlushSyncMichael Paquier2023-04-26
| | | | | | | | | | | SLRUFlushSync has been accidently removed during dee663f, that has moved the flush of the SLRU files to the checkpointer, so add it back. The issue has been noticed by Thomas when checking for orphaned wait events. Author: Thomas Munro Reviewed-by: Bharath Rupireddy Discussion: https://postgr.es/m/CA+hUKGK6tqm59KuF1z+h5Y8fsWcu5v8+84kduSHwRzwjB2aa_A@mail.gmail.com
* Fix custom validators call in build_local_reloptions()Alexander Korotkov2023-04-23
| | | | | | | | | | | We need to call them only when validate == true. Backpatch to 13, where opclass options were introduced. Reported-by: Tom Lane Discussion: https://postgr.es/m/2656633.1681831542%40sss.pgh.pa.us Reviewed-by: Tom Lane, Pavel Borisov Backpatch-through: 13
* Use nbtdesc "level" field name consistently.Peter Geoghegan2023-04-19
| | | | | | | | | | | The "lev" name that appeared in NEWROOT nbtree record desc output was inconsistent with the symbol name from the underlying C struct. It was also inconsistent with nbtdesc output for other nearby record types with similar level fields. Standardize on "level" to make everything consistent. Follow-up to commit 1c453cfd.
* Fix wal_consistency_checking enhanced desc output.Peter Geoghegan2023-04-19
| | | | | | | | | | | | | | | | | | | | Recent enhancements to rmgr desc routines that made the output summarize certain block data (added by commits 7d8219a4 and 1c453cfd) dealt with records that lack relevant block data (and so have nothing to give a more detailed summary of) by testing !DecodedBkpBlock.has_image. As a result, more detailed descriptions of block data were not output when wal_consistency_checking was enabled. This bug affected records with summarizable block data that also happened to have an FPI that the REDO routine isn't supposed to apply (FPIs used for consistency checking purposes only). The presence of such an FPI was incorrectly taken to indicate the absence of block data. To fix, test DecodedBkpBlock.has_data, not !DecodedBkpBlock.has_image. This is the exact condition that we care about, not an inexact proxy. Author: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-Wzm5Sc9cBg1qWV_cEBfLNJCrW9FjS-SoHVt8FLA7Ldn8yg@mail.gmail.com
* Fix various typos and incorrect/outdated name referencesDavid Rowley2023-04-19
| | | | | Author: Alexander Lakhin Discussion: https://postgr.es/m/699beab4-a6ca-92c9-f152-f559caf6dc25@gmail.com
* Remove useless argument from nbtree dedup function.Peter Geoghegan2023-04-18
| | | | | | _bt_dedup_pass()'s heapRel argument hasn't been needed or used since commit cf2acaf4dc made deleting any existing LP_DEAD index tuples the caller's responsibility.
* Fix pg_basebackup with in-place tablespaces some more.Robert Haas2023-04-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c6f2f01611d4f2c412e92eb7893f76fa590818e8 purported to make this work, but problems remained. In a plain-format backup, the files from an in-place tablespace got included in the tar file for the main tablespace, which is wrong but it's not clear that it has any user-visible consequences. In a tar-format backup, the TABLESPACE_MAP option is used, and so we never iterated over pg_tblspc and thus never backed up the in-place tablespaces anywhere at all. To fix this, reverse the changes in that commit, so that when we scan pg_tblspc during a backup, we create tablespaceinfo objects even for in-place tablespaces. We set the field that would normally contain the absolute pathname to the relative path pg_tblspc/${TSOID}, and that's good enough to make basebackup.c happy without any further changes. However, pg_basebackup needs a couple of adjustments to make it work. First, it needs to understand that a relative path for a tablespace means it's an in-place tablespace. Second, it needs to tolerate the situation where restoring the main tablespace tries to create pg_tblspc or a subdirectory and finds that it already exists, because we restore user-defined tablespaces before the main tablespace. Since in-place tablespaces are only intended for use in development and testing, no back-patch. Patch by me, reviewed by Thomas Munro and Michael Paquier. Discussion: http://postgr.es/m/CA+TgmobwvbEp+fLq2PykMYzizcvuNv0a7gPMJtxOTMOuuRLMHg@mail.gmail.com
* Avoid trying to write an empty WAL record in log_newpage_range().Tom Lane2023-04-17
| | | | | | | | | | | | | | | | | | | If the last few pages in the specified range are empty (all zero), then log_newpage_range() could try to emit an empty WAL record containing no FPIs. This at least upsets an Assert in ReserveXLogInsertLocation, and might perhaps have bad real-world consequences in non-assert builds. This has been broken since log_newpage_range() was introduced, but the case was hard if not impossible to hit before commit 3d6a98457 decided it was okay to leave VM and FSM pages intentionally zero. Nonetheless, it seems prudent to back-patch. log_newpage_range() was added in v12 but later back-patched, so this affects all supported branches. Matthias van de Meent, per report from Justin Pryzby Discussion: https://postgr.es/m/ZD1daibg4RF50IOj@telsasoft.com
* Fix incorrect format placeholdersPeter Eisentraut2023-04-12
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* Refine the guidelines for rmgrdesc authors.Peter Geoghegan2023-04-11
| | | | | | | | | | | | | | | | Clarify the goals of the recently added guidelines for rmgrdesc authors: to avoid gratuitous inconsistencies across resource managers, and to make it reasonably easy to write a reusable custom parser. Beyond that, the guidelines leave rmgrdesc authors with a significant amount of leeway. This even includes the leeway to invent custom conventions (in cases where it's warranted). Follow-up to commit 7d8219a4. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/CAH2-WzkbYuvwYKm-Y-72QEh6SPMQcAo9uONv+mR3bMGcu9E_Cg@mail.gmail.com
* Fix Heap rmgr's desc output for infobits arrays.Peter Geoghegan2023-04-11
| | | | | | | | | | | | | | | | | | | Make heap desc routines that output status bit as arrays of constants avoid outputting array literals that contain superfluous punctuation characters that complicate parsing the output. Also make sure that no heap desc routine repeats the same key name (at the same nesting level), for the same reason. Arguably, these were both oversights in commit 7d8219a4. In passing, make the desc output code (which covers Heap's DELETE, UPDATE, HOT_UPDATE, LOCK, and LOCK_UPDATED record types) consistent in terms of the output order of each field. This order also matches WAL record struct order. Heap's DELETE desc output now shows the record's xmax field for the first time (just like UPDATE/HOT_UPDATE records). Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/CAH2-Wz=pNYtxiJ2Jx5Lj=fKo1OEZ4GE0p_kct+ugAUTqBwU46g@mail.gmail.com
* Fix xl_heap_lock WAL record field's data type.Peter Geoghegan2023-04-11
| | | | | | | | | | | | | | Make xl_heap_lock's infobits_set field of type uint8, not int8. Using int8 isn't appropriate given that the field just holds status bits. This fixes an oversight in commit 0ac5ad5134. In passing rename the nearby TransactionId field to "xmax" to make things consistency with related records, such as xl_heap_lock_updated. Deliberately avoid a bump in XLOG_PAGE_MAGIC. No backpatch, either. Author: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-WzkCd3kOS8b7Rfxw7Mh1_6jvX=Nzo-CWR1VBTiOtVZkWHA@mail.gmail.com
* Clarify nbtree posting list update desc issue.Peter Geoghegan2023-04-10
| | | | | | | | | Per complaint from Melanie Plageman. Follow-up to commit 5d6728e5. Reported-By: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/20230411002315.oyaicmcqrq2hb3ek@liskov
* Fix nbtree posting list update desc output.Peter Geoghegan2023-04-10
| | | | | | | | | | | | | | | | | | | | | | | | | We cannot use the generic array_desc approach with per-tuple nbtree posting list update metadata because array_desc can only deal with fixed width elements (e.g., page offset numbers). Using array_desc led to incorrect rmgr descriptions for updates from nbtree DELETE/VACUUM WAL records. To fix, add specialized code to describe the update metadata as array elements in desc output. We now iterate over the update metadata using an approach that matches related REDO routines. Also stop showing the updates offset number array separately in nbtree DELETE/VACUUM desc output. It's redundant information, since the same page offset numbers appear in the description of each individual update element. Also make some small tweaks to the way that we format arrays in all desc routines (not just nbtree desc routines) to make arrays a little less verbose. Oversight in commit 1c453cfd, which enhanced the nbtree rmgr desc routines. Author: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/CAH2-WzkbYuvwYKm-Y-72QEh6SPMQcAo9uONv+mR3bMGcu9E_Cg@mail.gmail.com
* Allow logical decoding on standbysAndres Freund2023-04-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unsurprisingly, this requires wal_level = logical to be set on the primary and standby. The infrastructure added in 26669757b6a ensures that slots are invalidated if the primary's wal_level is lowered. Creating a slot on a standby waits for a xl_running_xact record to be processed. If the primary is idle (and thus not emitting xl_running_xact records), that can take a while. To make that faster, this commit also introduces the pg_log_standby_snapshot() function. By executing it on the primary, completion of slot creation on the standby can be accelerated. Note that logical decoding on a standby does not itself enforce that required catalog rows are not removed. The user has to use physical replication slots + hot_standby_feedback or other measures to prevent that. If catalog rows required for a slot are removed, the slot is invalidated. See 6af1793954e for an overall design of logical decoding on a standby. Bumps catversion, for the addition of the pg_log_standby_snapshot() function. Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com> Author: Andres Freund <andres@anarazel.de> (in an older version) Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version) Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: FabrÌzio de Royes Mello <fabriziomello@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Reviewed-By: Robert Haas <robertmhaas@gmail.com>
* For cascading replication, wake physical and logical walsenders separatelyAndres Freund2023-04-08
| | | | | | | | | | | | | | | | | | | | | | Physical walsenders can't send data until it's been flushed; logical walsenders can't decode and send data until it's been applied. On the standby, the WAL is flushed first, which will only wake up physical walsenders; and then applied, which will only wake up logical walsenders. Previously, all walsenders were awakened when the WAL was flushed. That was fine for logical walsenders on the primary; but on the standby the flushed WAL would have been not applied yet, so logical walsenders were awakened too early. Per idea from Jeff Davis and Amit Kapila. Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com> Reviewed-By: Jeff Davis <pgsql@j-davis.com> Reviewed-By: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAA4eK1+zO5LUeisabX10c81LU-fWMKO4M9Wyg1cdkbW7Hqh6vQ@mail.gmail.com
* Handle logical slot conflicts on standbyAndres Freund2023-04-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During WAL replay on the standby, when a conflict with a logical slot is identified, invalidate such slots. There are two sources of conflicts: 1) Using the information added in 6af1793954e, logical slots are invalidated if required rows are removed 2) wal_level on the primary server is reduced to below logical Uses the infrastructure introduced in the prior commit. FIXME: add commit reference. Change InvalidatePossiblyObsoleteSlot() to use a recovery conflict to interrupt use of a slot, if called in the startup process. The new recovery conflict is added to pg_stat_database_conflicts, as confl_active_logicalslot. See 6af1793954e for an overall design of logical decoding on a standby. Bumps catversion for the addition of the pg_stat_database_conflicts column. Bumps PGSTAT_FILE_FORMAT_ID for the same reason. Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com> Author: Andres Freund <andres@anarazel.de> Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version) Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
* Support invalidating replication slots due to horizon and wal_levelAndres Freund2023-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Needed for logical decoding on a standby. Slots need to be invalidated because of the horizon if rows required for logical decoding are removed. If the primary's wal_level is lowered from 'logical', logical slots on the standby need to be invalidated. The new invalidation methods will be used in a subsequent commit. Logical slots that have been invalidated can be identified via the new pg_replication_slots.conflicting column. See 6af1793954e for an overall design of logical decoding on a standby. Bumps catversion for the addition of the new pg_replication_slots column. Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com> Author: Andres Freund <andres@anarazel.de> Author: Amit Khandekar <amitdkhan.pg@gmail.com> (in an older version) Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Reviewed-by: Amit Kapila <amit.kapila16@gmail.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/20230407075009.igg7be27ha2htkbt@awork3.anarazel.de
* Add io_direct setting (developer-only).Thomas Munro2023-04-08
| | | | | | | | | | | | | | | | | | | | | | | Provide a way to ask the kernel to use O_DIRECT (or local equivalent) where available for data and WAL files, to avoid or minimize kernel caching. This hurts performance currently and is not intended for end users yet. Later proposed work would introduce our own I/O clustering, read-ahead, etc to replace the facilities the kernel disables with this option. The only user-visible change, if the developer-only GUC is not used, is that this commit also removes the obscure logic that would activate O_DIRECT for the WAL when wal_sync_method=open_[data]sync and wal_level=minimal (which also requires max_wal_senders=0). Those are non-default and unlikely settings, and this behavior wasn't (correctly) documented. The same effect can be achieved with io_direct=wal. Author: Thomas Munro <thomas.munro@gmail.com> Author: Andres Freund <andres@anarazel.de> Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Discussion: https://postgr.es/m/CA%2BhUKGK1X532hYqJ_MzFWt0n1zt8trz980D79WbjwnT-yYLZpg%40mail.gmail.com
* Introduce PG_IO_ALIGN_SIZE and align all I/O buffers.Thomas Munro2023-04-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to have the option to use O_DIRECT/FILE_FLAG_NO_BUFFERING in a later commit, we need the addresses of user space buffers to be well aligned. The exact requirements vary by OS and file system (typically sectors and/or memory pages). The address alignment size is set to 4096, which is enough for currently known systems: it matches modern sectors and common memory page size. There is no standard governing O_DIRECT's requirements so we might eventually have to reconsider this with more information from the field or future systems. Aligning I/O buffers on memory pages is also known to improve regular buffered I/O performance. Three classes of I/O buffers for regular data pages are adjusted: (1) Heap buffers are now allocated with the new palloc_aligned() or MemoryContextAllocAligned() functions introduced by commit 439f6175. (2) Stack buffers now use a new struct PGIOAlignedBlock to respect PG_IO_ALIGN_SIZE, if possible with this compiler. (3) The buffer pool is also aligned in shared memory. WAL buffers were already aligned on XLOG_BLCKSZ. It's possible for XLOG_BLCKSZ to be configured smaller than PG_IO_ALIGNED_SIZE and thus for O_DIRECT WAL writes to fail to be well aligned, but that's a pre-existing condition and will be addressed by a later commit. BufFiles are not yet addressed (there's no current plan to use O_DIRECT for those, but they could potentially get some incidental speedup even in plain buffered I/O operations through better alignment). If we can't align stack objects suitably using the compiler extensions we know about, we disable the use of O_DIRECT by setting PG_O_DIRECT to 0. This avoids the need to consider systems that have O_DIRECT but can't align stack objects the way we want; such systems could in theory be supported with more work but we don't currently know of any such machines, so it's easier to pretend there is no O_DIRECT support instead. That's an existing and tested class of system. Add assertions that all buffers passed into smgrread(), smgrwrite() and smgrextend() are correctly aligned, unless PG_O_DIRECT is 0 (= stack alignment tricks may be unavailable) or the block size has been set too small to allow arrays of buffers to be all aligned. Author: Thomas Munro <thomas.munro@gmail.com> Author: Andres Freund <andres@anarazel.de> Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> Discussion: https://postgr.es/m/CA+hUKGK1X532hYqJ_MzFWt0n1zt8trz980D79WbjwnT-yYLZpg@mail.gmail.com
* Show more detail in nbtree rmgr descriptions.Peter Geoghegan2023-04-07
| | | | | | | | | | | | Show a detailed description of the page offset number arrays that appear in certain nbtree WAL records. Also brings nbtree desc routines in line with the guidelines established by recent commit 7d8219a4. Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-By: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/flat/20230109215842.fktuhesvayno6o4g%40awork3.anarazel.de
* Show more detail in heapam rmgr descriptions.Peter Geoghegan2023-04-07
| | | | | | | | | | | | | | | | | Add helper functions that output arrays in a standard format, and use the functions inside heapdesc routines. This allows tools like pg_walinspect to show a detailed description of the page offset number arrays for records like PRUNE and VACUUM (unless there was an FPI). Also document the conventions that desc routines should follow. Only the heapdesc routines follow the conventions for now, so they're just guidelines for the time being. Based on a suggestion from Andres Freund. Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-By: Peter Geoghegan <pg@bowt.ie> Discussion: https://postgr.es/m/flat/20230109215842.fktuhesvayno6o4g%40awork3.anarazel.de
* Add more protections in WAL record APIs against overflowsMichael Paquier2023-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds a limit to the size of an XLogRecord at 1020MB, based on a suggestion by Heikki Linnakangas. This counts for the overhead needed by the XLogReader when allocating the memory it needs to read a record in DecodeXLogRecordRequiredSpace(), based on the record size. An assertion based on that is added to detect that any additions in the XLogReader facilities would not cause any overflows. If that's ever the case, the upper bound allowed would need to be adjusted. Before this, it was possible for an external module to create WAL records large enough to be assembled but not replayable, causing failures when replaying such WAL records on standbys. One case mentioned where this is possible is the in-core function pg_logical_emit_message() (wrapper for LogLogicalMessage), that allows to emit WAL records with an arbitrary amount of data potentially higher than the replay limit of approximately 1GB (limit of a palloc, minus the overhead needed by a XLogReader). This commit is a follow-up of ffd1b6b that has added similar protections for the block-level data. Here, the checks are extended to the whole record length, mainrdata_len being extended from uint32 to uint64 with the routines registering buffer and record data still limited to uint32 to minimize the checks when assembling a record. All the error messages related to overflow checks are improved to provide more context about the error happening. Author: Matthias van de Meent Reviewed-by: Andres Freund, Heikki Linnakangas, Michael Paquier Discussion: https://postgr.es/m/CAEze2WgGiw+LZt+vHf8tWqB_6VxeLsMeoAuod0N=ij1q17n5pw@mail.gmail.com
* Use ExtendBufferedRelTo() in XLogReadBufferExtended()Andres Freund2023-04-06
| | | | | | | | | | | | | | Instead of extending the relation block-by-block, use ExtendBufferedRelTo(), introduced in 31966b151e6. This is faster and simpler. This also somewhat reduces the danger that disconnected segments pose (which can be "discovered" once the previous segment reaches SEGSIZE), as ExtendBufferedRelTo() won't extend past the block it has been asked. However, the risk of the content of such a disconnected segment being invalid remains. Discussion: https://postgr.es/m/20221029025420.eplyow6k7tgu6he3@awork3.anarazel.de Discussion: https://postgr.es/m/20230223010147.32oir7sb66slqnjk@awork3.anarazel.de
* hio: Use ExtendBufferedRelBy() to extend tables more efficientlyAndres Freund2023-04-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While we already had some form of bulk extension for relations, it was fairly limited. It only amortized the cost of acquiring the extension lock, the relation itself was still extended one-by-one. Bulk extension was also solely triggered by contention, not by the amount of data inserted. To address this, use ExtendBufferedRelBy(), introduced in 31966b151e6, to extend the relation. We try to extend the relation by multiple blocks in two situations: 1) The caller tells RelationGetBufferForTuple() that it will need multiple pages. For now that's only used by heap_multi_insert(), see commit FIXME. 2) If there is contention on the extension lock, use the number of waiters for the lock as a multiplier for the number of blocks to extend by. This is similar to what we already did. Previously we additionally multiplied the numbers of waiters by 20, but with the new relation extension infrastructure I could not see a benefit in doing so. Using the freespacemap to provide empty pages can cause significant contention, and adds measurable overhead, even if there is no contention. To reduce that, remember the blocks the relation was extended by in the BulkInsertState, in the extending backend. In case 1) from above, the blocks the extending backend needs are not entered into the FSM, as we know that we will need those blocks. One complication with using the FSM to record empty pages, is that we need to insert blocks into the FSM, when we already hold a buffer content lock. To avoid doing IO while holding a content lock, release the content lock before recording free space. Currently that opens a small window in which another backend could fill the block, if a concurrent VACUUM records the free space. If that happens, we retry, similar to the already existing case when otherBuffer is provided. In the future it might be worth closing the race by preventing VACUUM from recording the space in newly extended pages. This change provides very significant wins (3x at 16 clients, on my workstation) for concurrent COPY into a single relation. Even single threaded COPY is measurably faster, primarily due to not dirtying pages while extending, if supported by the operating system (see commit 4d330a61bb1). Even single-row INSERTs benefit, although to a much smaller degree, as the relation extension lock rarely is the primary bottleneck. Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/20221029025420.eplyow6k7tgu6he3@awork3.anarazel.de
* heapam: Pass number of required pages to RelationGetBufferForTuple()Andres Freund2023-04-06
| | | | | | | | | | A future commit will use this information to determine how aggressively to extend the relation by. In heap_multi_insert() we know accurately how many pages we need once we need to extend the relation, providing an accurate lower bound for how much to extend. Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/20221029025420.eplyow6k7tgu6he3@awork3.anarazel.de
* Refresh cost-based delay params more frequently in autovacuumDaniel Gustafsson2023-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow autovacuum to reload the config file more often so that cost-based delay parameters can take effect while VACUUMing a relation. Previously, autovacuum workers only reloaded the config file once per relation vacuumed, so config changes could not take effect until beginning to vacuum the next table. Now, check if a reload is pending roughly once per block, when checking if we need to delay. In order for autovacuum workers to safely update their own cost delay and cost limit parameters without impacting performance, we had to rethink when and how these values were accessed. Previously, an autovacuum worker's wi_cost_limit was set only at the beginning of vacuuming a table, after reloading the config file. Therefore, at the time that autovac_balance_cost() was called, workers vacuuming tables with no cost-related storage parameters could still have different values for their wi_cost_limit_base and wi_cost_delay. Now that the cost parameters can be updated while vacuuming a table, workers will (within some margin of error) have no reason to have different values for cost limit and cost delay (in the absence of cost-related storage parameters). This removes the rationale for keeping cost limit and cost delay in shared memory. Balancing the cost limit requires only the number of active autovacuum workers vacuuming a table with no cost-based storage parameters. Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/CAAKRu_ZngzqnEODc7LmS1NH04Kt6Y9huSjz5pp7%2BDXhrjDA0gw%40mail.gmail.com
* Make vacuum failsafe_active globally visibleDaniel Gustafsson2023-04-07
| | | | | | | | | | | | | | | | | | | While vacuuming a table in failsafe mode, VacuumCostActive should not be re-enabled. This currently isn't a problem because vacuum cost parameters are only refreshed in between vacuuming tables and failsafe status is reset for every table. In preparation for allowing vacuum cost parameters to be updated more frequently, elevate LVRelState->failsafe_active to a global, VacuumFailsafeActive, which will be checked when determining whether or not to re-enable vacuum cost-related delays. Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/CAAKRu_ZngzqnEODc7LmS1NH04Kt6Y9huSjz5pp7%2BDXhrjDA0gw%40mail.gmail.com
* hio: Don't pin the VM while holding buffer lock while extendingAndres Freund2023-04-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Starting with commit 7db0cd2145f, RelationGetBufferForTuple() did a visibilitymap_pin() while holding an exclusive buffer content lock on a newly extended page, when using COPY FREEZE. We elsewhere try hard to avoid to doing IO while holding a content lock. And until 14f98e0af99, that happened while holding the relation extension lock. Practically, this isn't a huge issue, because COPY FREEZE is restricted to relations created or truncated in the current session, so it's unlikely there's a lot of contention. We can't avoid doing IO while holding the content lock by pinning the VM earlier, because we don't know which page it will be on. While we could just ignore the issue in this case, a future commit will add bulk relation extension, which needs to enter pages into the FSM while also trying to hold onto a buffer lock. To address this issue, use visibilitymap_pin_ok() to see if the relevant buffer is already pinned. If not, release the buffer, pin the VM buffer, and acquire the lock again. This opens up a small window for other backends to insert data onto the page - as the page is not entered into the freespacemap, other backends won't see it normally, but a concurrent vacuum could enter the page, if it started just after the relation is extended. In case the page is used by another backend, retry. This is very similar to how locking "otherBuffer" is already dealt with. Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Discussion: http://postgr.es/m/20230325025740.wzvchp2kromw4zqz@awork3.anarazel.de