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* Unpin buffer before inplace update waits for an XID to end.Noah Misch2024-10-29
| | | | | | | | | | | | Commit a07e03fd8fa7daf4d1356f7cb501ffe784ea6257 changed inplace updates to wait for heap_update() commands like GRANT TABLE and GRANT DATABASE. By keeping the pin during that wait, a sequence of autovacuum workers and an uncommitted GRANT starved one foreground LockBufferForCleanup() for six minutes, on buildfarm member sarus. Prevent, at the cost of a bit of complexity. Back-patch to v12, like the earlier commit. That commit and heap_inplace_lock() have not yet appeared in any release. Discussion: https://postgr.es/m/20241026184936.ae.nmisch@google.com
* Fix fetching default toast value during decoding of in-progress transactions.Amit Kapila2024-10-07
| | | | | | | | | | | | | | | During logical decoding of in-progress transactions, we perform the toast table scan while fetching the default toast value for an attribute. We forgot to initialize the flag during this scan to indicate that the system table scan is in progress. We need this flag to ensure that during logical decoding we never directly access the tableam or heap APIs because we check for concurrent aborts only in systable_* APIs. Reported-by: Alexander Lakhin Author: Takeshi Ideriha, Hou Zhijie Reviewed-by: Amit Kapila, Hou Zhijie Backpatch-through: 14 Discussion: https://postgr.es/m/18641-6687273b7f15269d@postgresql.org
* For inplace update durability, make heap_update() callers wait.Noah Misch2024-09-24
| | | | | | | | | | | | | | | | | | | The previous commit fixed some ways of losing an inplace update. It remained possible to lose one when a backend working toward a heap_update() copied a tuple into memory just before inplace update of that tuple. In catalogs eligible for inplace update, use LOCKTAG_TUPLE to govern admission to the steps of copying an old tuple, modifying it, and issuing heap_update(). This includes MERGE commands. To avoid changing most of the pg_class DDL, don't require LOCKTAG_TUPLE when holding a relation lock sufficient to exclude inplace updaters. Back-patch to v12 (all supported versions). In v13 and v12, "UPDATE pg_class" or "UPDATE pg_database" can still lose an inplace update. The v14+ UPDATE fix needs commit 86dc90056dfdbd9d1b891718d2e5614e3e432f35, and it wasn't worth reimplementing that fix without such infrastructure. Reviewed by Nitin Motiani and (in earlier versions) Heikki Linnakangas. Discussion: https://postgr.es/m/20231027214946.79.nmisch@google.com
* Fix data loss at inplace update after heap_update().Noah Misch2024-09-24
| | | | | | | | | | | | | | | | | | | | | | As previously-added tests demonstrated, heap_inplace_update() could instead update an unrelated tuple of the same catalog. It could lose the update. Losing relhasindex=t was a source of index corruption. Inplace-updating commands like VACUUM will now wait for heap_update() commands like GRANT TABLE and GRANT DATABASE. That isn't ideal, but a long-running GRANT already hurts VACUUM progress more just by keeping an XID running. The VACUUM will behave like a DELETE or UPDATE waiting for the uncommitted change. For implementation details, start at the systable_inplace_update_begin() header comment and README.tuplock. Back-patch to v12 (all supported versions). In back branches, retain a deprecated heap_inplace_update(), for extensions. Reported by Smolkin Grigory. Reviewed by Nitin Motiani, (in earlier versions) Heikki Linnakangas, and (in earlier versions) Alexander Lakhin. Discussion: https://postgr.es/m/CAMp+ueZQz3yDk7qg42hk6-9gxniYbp-=bG2mgqecErqR5gGGOA@mail.gmail.com
* Improve Asserts checking relation matching in parallel scans.Tom Lane2024-09-20
| | | | | | | | | | | | | | | | table_beginscan_parallel and index_beginscan_parallel contain Asserts checking that the relation a worker will use in a parallel scan is the same one the leader intended. However, they were checking for relation OID match, which was not strong enough to detect the mismatch problem fixed in 126ec0bc7. What would be strong enough is to compare relfilenodes instead. Arguably, that's a saner definition anyway, since a scan surely operates on a physical relation not a logical one. Hence, store and compare RelFileLocators not relation OIDs. Also ensure that index_beginscan_parallel checks the index identity not just the table identity. Discussion: https://postgr.es/m/2127254.1726789524@sss.pgh.pa.us
* Don't overwrite scan key in systable_beginscan()Peter Eisentraut2024-09-12
| | | | | | | | | | | | | | | | | | | | When systable_beginscan() and systable_beginscan_ordered() choose an index scan, they remap the attribute numbers in the passed-in scan keys to the attribute numbers of the index, and then write those remapped attribute numbers back into the scan key passed by the caller. This second part is surprising and gratuitous. It means that a scan key cannot safely be used more than once (but it might sometimes work, depending on circumstances). Also, there is no value in providing these remapped attribute numbers back to the caller, since they can't do anything with that. Fix that by making a copy of the scan keys passed by the caller and make the modifications there. Also, some code that had to work around the previous situation is simplified. Discussion: https://www.postgresql.org/message-id/flat/f8c739d9-f48d-4187-b214-df3391ba41ab@eisentraut.org
* Log the conflicts while applying changes in logical replication.Amit Kapila2024-08-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch provides the additional logging information in the following conflict scenarios while applying changes: insert_exists: Inserting a row that violates a NOT DEFERRABLE unique constraint. update_differ: Updating a row that was previously modified by another origin. update_exists: The updated row value violates a NOT DEFERRABLE unique constraint. update_missing: The tuple to be updated is missing. delete_differ: Deleting a row that was previously modified by another origin. delete_missing: The tuple to be deleted is missing. For insert_exists and update_exists conflicts, the log can include the origin and commit timestamp details of the conflicting key with track_commit_timestamp enabled. update_differ and delete_differ conflicts can only be detected when track_commit_timestamp is enabled on the subscriber. We do not offer additional logging for exclusion constraint violations because these constraints can specify rules that are more complex than simple equality checks. Resolving such conflicts won't be straightforward. This area can be further enhanced if required. Author: Hou Zhijie Reviewed-by: Shveta Malik, Amit Kapila, Nisha Moond, Hayato Kuroda, Dilip Kumar Discussion: https://postgr.es/m/OS0PR01MB5716352552DFADB8E9AD1D8994C92@OS0PR01MB5716.jpnprd01.prod.outlook.com
* Add missing index_insert_cleanup callsTomas Vondra2024-04-19
| | | | | | | | | | | | | | | | | | | | | | | The optimization for inserts into BRIN indexes added by c1ec02be1d79 relies on a cache that needs to be explicitly released after calling index_insert(). The commit however failed to invoke the cleanup in validate_index(), which calls index_insert() indirectly through table_index_validate_scan(). After inspecting index_insert() callers, it seems unique_key_recheck() is missing the call too. Fixed by adding the two missing index_insert_cleanup() calls. The commit does two additional improvements. The aminsertcleanup() signature is modified to have the index as the first argument, to make it more like the other AM callbacks. And the aminsertcleanup() callback is invoked even if the ii_AmCache is NULL, so that it can decide if the cleanup is necessary. Author: Alvaro Herrera, Tomas Vondra Reported-by: Alexander Lakhin Discussion: https://postgr.es/m/202401091043.e3nrqiad6gb7@alvherre.pgsql
* Enhance nbtree ScalarArrayOp execution.Peter Geoghegan2024-04-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 9e8da0f7 taught nbtree to handle ScalarArrayOpExpr quals natively. This works by pushing down the full context (the array keys) to the nbtree index AM, enabling it to execute multiple primitive index scans that the planner treats as one continuous index scan/index path. This earlier enhancement enabled nbtree ScalarArrayOp index-only scans. It also allowed scans with ScalarArrayOp quals to return ordered results (with some notable restrictions, described further down). Take this general approach a lot further: teach nbtree SAOP index scans to decide how to execute ScalarArrayOp scans (when and where to start the next primitive index scan) based on physical index characteristics. This can be far more efficient. All SAOP scans will now reliably avoid duplicative leaf page accesses (just like any other nbtree index scan). SAOP scans whose array keys are naturally clustered together now require far fewer index descents, since we'll reliably avoid starting a new primitive scan just to get to a later offset from the same leaf page. The scan's arrays now advance using binary searches for the array element that best matches the next tuple's attribute value. Required scan key arrays (i.e. arrays from scan keys that can terminate the scan) ratchet forward in lockstep with the index scan. Non-required arrays (i.e. arrays from scan keys that can only exclude non-matching tuples) "advance" without the process ever rolling over to a higher-order array. Naturally, only required SAOP scan keys trigger skipping over leaf pages (non-required arrays cannot safely end or start primitive index scans). Consequently, even index scans of a composite index with a high-order inequality scan key (which we'll mark required) and a low-order SAOP scan key (which we won't mark required) now avoid repeating leaf page accesses -- that benefit isn't limited to simpler equality-only cases. In general, all nbtree index scans now output tuples as if they were one continuous index scan -- even scans that mix a high-order inequality with lower-order SAOP equalities reliably output tuples in index order. This allows us to remove a couple of special cases that were applied when building index paths with SAOP clauses during planning. Bugfix commit 807a40c5 taught the planner to avoid generating unsafe path keys: path keys on a multicolumn index path, with a SAOP clause on any attribute beyond the first/most significant attribute. These cases are now all safe, so we go back to generating path keys without regard for the presence of SAOP clauses (just like with any other clause type). Affected queries can now exploit scan output order in all the usual ways (e.g., certain "ORDER BY ... LIMIT n" queries can now terminate early). Also undo changes from follow-up bugfix commit a4523c5a, which taught the planner to produce alternative index paths, with path keys, but without low-order SAOP index quals (filter quals were used instead). We'll no longer generate these alternative paths, since they can no longer offer any meaningful advantages over standard index qual paths. Affected queries thereby avoid all of the disadvantages that come from using filter quals within index scan nodes. They can avoid extra heap page accesses from using filter quals to exclude non-matching tuples (index quals will never have that problem). They can also skip over irrelevant sections of the index in more cases (though only when nbtree determines that starting another primitive scan actually makes sense). There is a theoretical risk that removing restrictions on SAOP index paths from the planner will break compatibility with amcanorder-based index AMs maintained as extensions. Such an index AM could have the same limitations around ordered SAOP scans as nbtree had up until now. Adding a pro forma incompatibility item about the issue to the Postgres 17 release notes seems like a good idea. Author: Peter Geoghegan <pg@bowt.ie> Author: Matthias van de Meent <boekewurm+postgres@gmail.com> Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com> Reviewed-By: Tomas Vondra <tomas.vondra@enterprisedb.com> Discussion: https://postgr.es/m/CAH2-Wz=ksvN_sjcnD1+Bt-WtifRA5ok48aDYnq3pkKhxgMQpcw@mail.gmail.com
* Remove unused #include's from backend .c filesPeter Eisentraut2024-03-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | as determined by include-what-you-use (IWYU) While IWYU also suggests to *add* a bunch of #include's (which is its main purpose), this patch does not do that. In some cases, a more specific #include replaces another less specific one. Some manual adjustments of the automatic result: - IWYU currently doesn't know about includes that provide global variable declarations (like -Wmissing-variable-declarations), so those includes are being kept manually. - All includes for port(ability) headers are being kept for now, to play it safe. - No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the patch from exploding in size. Note that this patch touches just *.c files, so nothing declared in header files changes in hidden ways. As a small example, in src/backend/access/transam/rmgr.c, some IWYU pragma annotations are added to handle a special case there. Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org
* Promote assertion about !ReindexIsProcessingIndex to runtime error.Tom Lane2024-02-25
| | | | | | | | | | | | | | | | | | | | | When this assertion was installed (in commit d2f60a3ab), I thought it was only for catching server logic errors that caused accesses to catalogs that were undergoing index rebuilds. However, it will also fire in case of a user-defined index expression that attempts to access its own table. We occasionally see reports of people trying to do that, and typically getting unintelligible low-level errors as a result. We can provide a more on-point message by making this a regular runtime check. While at it, adjust the similar error check in systable_beginscan_ordered to use the same message text. That one is (probably) not reachable without a coding bug, but we might as well use a translatable message if we have one. Per bug #18363 from Alexander Lakhin. Back-patch to all supported branches. Discussion: https://postgr.es/m/18363-e3598a5a572d0699@postgresql.org
* Fix some typosMichael Paquier2024-01-22
| | | | | Author: Yongtao Huang Discussion: https://postgr.es/m/CAOe1Go1F99o5JsphtXdDC5bxm7AzetU8q3AxLh4AAVGKu1AzEQ@mail.gmail.com
* Add try_index_open(), conditional variant of index_open()Michael Paquier2024-01-18
| | | | | | | | | | | | | | try_index_open() is able to open an index if its relkind fits, except that it would return NULL instead of generated an error if the relation does not exist. This new routine will be used by an upcoming patch to make REINDEX on partitioned relations more robust when an index in a partition tree is dropped. Extracted from a larger patch by the same author. Author: Fei Changhong Discussion: https://postgr.es/m/tencent_6A52106095ACDE55333E3AD33F304C0C3909@qq.com Backpatch-through: 14
* Update copyright for 2024Bruce Momjian2024-01-03
| | | | | | | | Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
* Check if ii_AmCache is NULL in aminsertcleanupTomas Vondra2023-11-27
| | | | | | | | | | | | | | Fix a bug introduced by c1ec02be1d79. It may happen that the executor opens indexes on the result relation, but no rows end up being inserted. Then the index_insert_cleanup still gets executed, but passes down NULL to the AM callback. The AM callback may not expect this, as is the case of brininsertcleanup, leading to a crash. Fixed by only calling the cleanup callback if (ii_AmCache != NULL). This way the AM can simply assume to only see a valid cache. Reported-by: Richard Guo Discussion: https://postgr.es/m/CAMbWs4-w9qC-o9hQox9UHvdVZAYTp8OrPQOKtwbvzWaRejTT=Q@mail.gmail.com
* Reuse BrinDesc and BrinRevmap in brininsertTomas Vondra2023-11-25
| | | | | | | | | | | | | | | | The brininsert code used to initialize (and destroy) BrinDesc and BrinRevmap for each tuple, which is not free. This patch initializes these structures only once, and reuses them for all inserts in the same command. The data is passed through indexInfo->ii_AmCache. This also introduces an optional AM callback "aminsertcleanup" that allows performing custom cleanup in case simply pfree-ing ii_AmCache is not sufficient (which is the case when the cache contains TupleDesc, Buffers, and so on). Author: Soumyadeep Chakraborty Reviewed-by: Alvaro Herrera, Matthias van de Meent, Tomas Vondra Discussion: https://postgr.es/m/CAE-ML%2B9r2%3DaO1wwji1sBN9gvPz2xRAtFUGfnffpd0ZqyuzjamA%40mail.gmail.com
* Add const to values and nulls argumentsPeter Eisentraut2023-10-10
| | | | | | | This excludes any changes that would change the external AM APIs. Reviewed-by: Aleksander Alekseev <aleksander@timescale.com> Discussion: https://www.postgresql.org/message-id/flat/14c31f4a-0347-0805-dce8-93a9072c05a5%40eisentraut.org
* Add SysCacheGetAttrNotNull for guaranteed not-null attrsDaniel Gustafsson2023-03-25
| | | | | | | | | | | | | When extracting an attr from a cached tuple in the syscache with SysCacheGetAttr the isnull parameter must be checked in case the attr cannot be NULL. For cases when this is known beforehand, a wrapper is introduced which perform the errorhandling internally on behalf of the caller, invoking an elog in case of a NULL attr. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com> Reviewed-by: David Rowley <dgrowleyml@gmail.com> Discussion: https://postgr.es/m/AD76405E-DB45-46B6-941F-17B1EB3A9076@yesql.se
* Update copyright for 2023Bruce Momjian2023-01-02
| | | | Backpatch-through: 11
* Add copyright notices to meson filesAndrew Dunstan2022-12-20
| | | | Discussion: https://postgr.es/m/222b43a5-2fb3-2c1b-9cd0-375d376c8246@dunslane.net
* Check the snapshot argument of index_beginscan and familyAlexander Korotkov2022-12-06
| | | | | | | | | | | | Passing a NULL snapshot (InvalidSnapshot) is going to work but only as long as the index can't find any matching rows. This can be confusing for the extension authors, so add an explicit check for this argument. The check is implemented with Assert() in order to avoid overhead in release builds. Reported-by: Sven Klemm Discussion: https://postgr.es/m/CAJ7c6TPxitD4vbKyP-mpmC1XwyHdPPqvjLzm%2BVpB88h8LGgneQ%40mail.gmail.com Author: Aleksander Alekseev Reviewed-by: Pavel Borisov
* Standardize rmgrdesc recovery conflict XID output.Peter Geoghegan2022-11-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Standardize on the name snapshotConflictHorizon for all XID fields from WAL records that generate recovery conflicts when in hot standby mode. This supersedes the previous latestRemovedXid naming convention. The new naming convention places emphasis on how the values are actually used by REDO routines. How the values are generated during original execution (details of which vary by record type) is deemphasized. Users of tools like pg_waldump can now grep for snapshotConflictHorizon to see all potential sources of recovery conflicts in a standardized way, without necessarily having to consider which specific record types might be involved. Also bring a couple of WAL record types that didn't follow any kind of naming convention into line. These are heapam's VISIBLE record type and SP-GiST's VACUUM_REDIRECT record type. Now every WAL record whose REDO routine calls ResolveRecoveryConflictWithSnapshot() passes through the snapshotConflictHorizon field from its WAL record. This is follow-up work to the refactoring from commit 9e540599 that made FREEZE_PAGE WAL records use a standard snapshotConflictHorizon style XID cutoff. No bump in XLOG_PAGE_MAGIC, since the underlying format of affected WAL records doesn't change. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/CAH2-Wzm2CQUmViUq7Opgk=McVREHSOorYaAjR1ZpLYkRN7_dPw@mail.gmail.com
* meson: Add initial version of meson based build systemAndres Freund2022-09-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Autoconf is showing its age, fewer and fewer contributors know how to wrangle it. Recursive make has a lot of hard to resolve dependency issues and slow incremental rebuilds. Our home-grown MSVC build system is hard to maintain for developers not using Windows and runs tests serially. While these and other issues could individually be addressed with incremental improvements, together they seem best addressed by moving to a more modern build system. After evaluating different build system choices, we chose to use meson, to a good degree based on the adoption by other open source projects. We decided that it's more realistic to commit a relatively early version of the new build system and mature it in tree. This commit adds an initial version of a meson based build system. It supports building postgres on at least AIX, FreeBSD, Linux, macOS, NetBSD, OpenBSD, Solaris and Windows (however only gcc is supported on aix, solaris). For Windows/MSVC postgres can now be built with ninja (faster, particularly for incremental builds) and msbuild (supporting the visual studio GUI, but building slower). Several aspects (e.g. Windows rc file generation, PGXS compatibility, LLVM bitcode generation, documentation adjustments) are done in subsequent commits requiring further review. Other aspects (e.g. not installing test-only extensions) are not yet addressed. When building on Windows with msbuild, builds are slower when using a visual studio version older than 2019, because those versions do not support MultiToolTask, required by meson for intra-target parallelism. The plan is to remove the MSVC specific build system in src/tools/msvc soon after reaching feature parity. However, we're not planning to remove the autoconf/make build system in the near future. Likely we're going to keep at least the parts required for PGXS to keep working around until all supported versions build with meson. Some initial help for postgres developers is at https://wiki.postgresql.org/wiki/Meson With contributions from Thomas Munro, John Naylor, Stone Tickle and others. Author: Andres Freund <andres@anarazel.de> Author: Nazir Bilal Yavuz <byavuz81@gmail.com> Author: Peter Eisentraut <peter@eisentraut.org> Reviewed-By: Peter Eisentraut <peter.eisentraut@enterprisedb.com> Discussion: https://postgr.es/m/20211012083721.hvixq4pnh2pixr3j@alap3.anarazel.de
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Add hardening to catch invalid TIDs in indexes.Peter Geoghegan2021-11-04
| | | | | | | | | | | | | | | | | | | Add hardening to the heapam index tuple deletion path to catch TIDs in index pages that point to a heap item that index tuples should never point to. The corruption we're trying to catch here is particularly tricky to detect, since it typically involves "extra" (corrupt) index tuples, as opposed to the absence of required index tuples in the index. For example, a heap TID from an index page that turns out to point to an LP_UNUSED item in the heap page has a good chance of being caught by one of the new checks. There is a decent chance that the recently fixed parallel VACUUM bug (see commit 9bacec15) would have been caught had that particular check been in place for Postgres 14. No backpatch of this extra hardening for now, though. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/CAH2-Wzk-4_raTzawWGaiqNvkpwDXxv3y1AQhQyUeHfkU=tFCeA@mail.gmail.com
* Initial pgindent and pgperltidy run for v14.Tom Lane2021-05-12
| | | | | | | | Also "make reformat-dat-files". The only change worthy of note is that pgindent messed up the formatting of launcher.c's struct LogicalRepWorkerId, which led me to notice that that struct wasn't used at all anymore, so I just took it out.
* Fix typos and grammar in comments and docsMichael Paquier2021-04-19
| | | | | Author: Justin Pryzby Discussion: https://postgr.es/m/20210416070310.GG3315@telsasoft.com
* Improve quoting in some error messagesPeter Eisentraut2021-04-14
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* Simplify state managed by VACUUM.Peter Geoghegan2021-04-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reorganize the state struct used by VACUUM -- group related items together to make it easier to understand. Also stop relying on stack variables inside lazy_scan_heap() -- move those into the state struct instead. Doing things this way simplifies large groups of related functions whose function signatures had a lot of unnecessary redundancy. Switch over to using int64 for the struct fields used to count things that are reported to the user via log_autovacuum and VACUUM VERBOSE output. We were using double, but that doesn't seem to have any advantages. Using int64 makes it possible to add assertions that verify that the first pass over the heap (pruning) encounters precisely the same number of LP_DEAD items that get deleted from indexes later on, in the second pass over the heap. These assertions will be added in later commits. Finally, adjust the signatures of functions with IndexBulkDeleteResult pointer arguments in cases where there was ambiguity about whether or not the argument relates to a single index or all indexes. Functions now use the idiom that both ambulkdelete() and amvacuumcleanup() have always used (where appropriate): accept a mutable IndexBulkDeleteResult pointer argument, and return a result IndexBulkDeleteResult pointer to caller. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Reviewed-By: Robert Haas <robertmhaas@gmail.com> Discussion: https://postgr.es/m/CAH2-WzkeOSYwC6KNckbhk2b1aNnWum6Yyn0NKP9D-Hq1LGTDPw@mail.gmail.com
* Fix GiST index deletion assert issue.Peter Geoghegan2021-01-26
| | | | | | | | | | | | | Avoid calling heap_index_delete_tuples() with an empty deltids array to avoid an assertion failure. This issue was arguably an oversight in commit b5f58cf2, though the failing assert itself was added by my recent commit d168b666. No backpatch, though, since the oversight is harmless in the back branches. Author: Peter Geoghegan <pg@bowt.ie> Reported-By: Jaime Casanova <jcasanov@systemguards.com.ec> Discussion: https://postgr.es/m/CAJKUy5jscES84n3puE=sYngyF+zpb4wv8UMtuLnLPv5z=6yyNw@mail.gmail.com
* Enhance nbtree index tuple deletion.Peter Geoghegan2021-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Teach nbtree and heapam to cooperate in order to eagerly remove duplicate tuples representing dead MVCC versions. This is "bottom-up deletion". Each bottom-up deletion pass is triggered lazily in response to a flood of versions on an nbtree leaf page. This usually involves a "logically unchanged index" hint (these are produced by the executor mechanism added by commit 9dc718bd). The immediate goal of bottom-up index deletion is to avoid "unnecessary" page splits caused entirely by version duplicates. It naturally has an even more useful effect, though: it acts as a backstop against accumulating an excessive number of index tuple versions for any given _logical row_. Bottom-up index deletion complements what we might now call "top-down index deletion": index vacuuming performed by VACUUM. Bottom-up index deletion responds to the immediate local needs of queries, while leaving it up to autovacuum to perform infrequent clean sweeps of the index. The overall effect is to avoid certain pathological performance issues related to "version churn" from UPDATEs. The previous tableam interface used by index AMs to perform tuple deletion (the table_compute_xid_horizon_for_tuples() function) has been replaced with a new interface that supports certain new requirements. Many (perhaps all) of the capabilities added to nbtree by this commit could also be extended to other index AMs. That is left as work for a later commit. Extend deletion of LP_DEAD-marked index tuples in nbtree by adding logic to consider extra index tuples (that are not LP_DEAD-marked) for deletion in passing. This increases the number of index tuples deleted significantly in many cases. The LP_DEAD deletion process (which is now called "simple deletion" to clearly distinguish it from bottom-up deletion) won't usually need to visit any extra table blocks to check these extra tuples. We have to visit the same table blocks anyway to generate a latestRemovedXid value (at least in the common case where the index deletion operation's WAL record needs such a value). Testing has shown that the "extra tuples" simple deletion enhancement increases the number of index tuples deleted with almost any workload that has LP_DEAD bits set in leaf pages. That is, it almost never fails to delete at least a few extra index tuples. It helps most of all in cases that happen to naturally have a lot of delete-safe tuples. It's not uncommon for an individual deletion operation to end up deleting an order of magnitude more index tuples compared to the old naive approach (e.g., custom instrumentation of the patch shows that this happens fairly often when the regression tests are run). Add a further enhancement that augments simple deletion and bottom-up deletion in indexes that make use of deduplication: Teach nbtree's _bt_delitems_delete() function to support granular TID deletion in posting list tuples. It is now possible to delete individual TIDs from posting list tuples provided the TIDs have a tableam block number of a table block that gets visited as part of the deletion process (visiting the table block can be triggered directly or indirectly). Setting the LP_DEAD bit of a posting list tuple is still an all-or-nothing thing, but that matters much less now that deletion only needs to start out with the right _general_ idea about which index tuples are deletable. Bump XLOG_PAGE_MAGIC because xl_btree_delete changed. No bump in BTREE_VERSION, since there are no changes to the on-disk representation of nbtree indexes. Indexes built on PostgreSQL 12 or PostgreSQL 13 will automatically benefit from bottom-up index deletion (i.e. no reindexing required) following a pg_upgrade. The enhancement to simple deletion is available with all B-Tree indexes following a pg_upgrade, no matter what PostgreSQL version the user upgrades from. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-By: Victor Yegorov <vyegorov@gmail.com> Discussion: https://postgr.es/m/CAH2-Wzm+maE3apHB8NOtmM=p-DO65j2V5GzAWCOEEuy3JZgb2g@mail.gmail.com
* Pass down "logically unchanged index" hint.Peter Geoghegan2021-01-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add an executor aminsert() hint mechanism that informs index AMs that the incoming index tuple (the tuple that accompanies the hint) is not being inserted by execution of an SQL statement that logically modifies any of the index's key columns. The hint is received by indexes when an UPDATE takes place that does not apply an optimization like heapam's HOT (though only for indexes where all key columns are logically unchanged). Any index tuple that receives the hint on insert is expected to be a duplicate of at least one existing older version that is needed for the same logical row. Related versions will typically be stored on the same index page, at least within index AMs that apply the hint. Recognizing the difference between MVCC version churn duplicates and true logical row duplicates at the index AM level can help with cleanup of garbage index tuples. Cleanup can intelligently target tuples that are likely to be garbage, without wasting too many cycles on less promising tuples/pages (index pages with little or no version churn). This is infrastructure for an upcoming commit that will teach nbtree to perform bottom-up index deletion. No index AM actually applies the hint just yet. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Victor Yegorov <vyegorov@gmail.com> Discussion: https://postgr.es/m/CAH2-Wz=CEKFa74EScx_hFVshCOn6AA5T-ajFASTdzipdkLTNQQ@mail.gmail.com
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* snapshot scalability: Don't compute global horizons while building snapshots.Andres Freund2020-08-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To make GetSnapshotData() more scalable, it cannot not look at at each proc's xmin: While snapshot contents do not need to change whenever a read-only transaction commits or a snapshot is released, a proc's xmin is modified in those cases. The frequency of xmin modifications leads to, particularly on higher core count systems, many cache misses inside GetSnapshotData(), despite the data underlying a snapshot not changing. That is the most significant source of GetSnapshotData() scaling poorly on larger systems. Without accessing xmins, GetSnapshotData() cannot calculate accurate horizons / thresholds as it has so far. But we don't really have to: The horizons don't actually change that much between GetSnapshotData() calls. Nor are the horizons actually used every time a snapshot is built. The trick this commit introduces is to delay computation of accurate horizons until there use and using horizon boundaries to determine whether accurate horizons need to be computed. The use of RecentGlobal[Data]Xmin to decide whether a row version could be removed has been replaces with new GlobalVisTest* functions. These use two thresholds to determine whether a row can be pruned: 1) definitely_needed, indicating that rows deleted by XIDs >= definitely_needed are definitely still visible. 2) maybe_needed, indicating that rows deleted by XIDs < maybe_needed can definitely be removed GetSnapshotData() updates definitely_needed to be the xmin of the computed snapshot. When testing whether a row can be removed (with GlobalVisTestIsRemovableXid()) and the tested XID falls in between the two (i.e. XID >= maybe_needed && XID < definitely_needed) the boundaries can be recomputed to be more accurate. As it is not cheap to compute accurate boundaries, we limit the number of times that happens in short succession. As the boundaries used by GlobalVisTestIsRemovableXid() are never reset (with maybe_needed updated by GetSnapshotData()), it is likely that further test can benefit from an earlier computation of accurate horizons. To avoid regressing performance when old_snapshot_threshold is set (as that requires an accurate horizon to be computed), heap_page_prune_opt() doesn't unconditionally call TransactionIdLimitedForOldSnapshots() anymore. Both the computation of the limited horizon, and the triggering of errors (with SetOldSnapshotThresholdTimestamp()) is now only done when necessary to remove tuples. This commit just removes the accesses to PGXACT->xmin from GetSnapshotData(), but other members of PGXACT residing in the same cache line are accessed. Therefore this in itself does not result in a significant improvement. Subsequent commits will take advantage of the fact that GetSnapshotData() now does not need to access xmins anymore. Note: This contains a workaround in heap_page_prune_opt() to keep the snapshot_too_old tests working. While that workaround is ugly, the tests currently are not meaningful, and it seems best to address them separately. Author: Andres Freund <andres@anarazel.de> Reviewed-By: Robert Haas <robertmhaas@gmail.com> Reviewed-By: Thomas Munro <thomas.munro@gmail.com> Reviewed-By: David Rowley <dgrowleyml@gmail.com> Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
* Implement streaming mode in ReorderBuffer.Amit Kapila2020-08-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of serializing the transaction to disk after reaching the logical_decoding_work_mem limit in memory, we consume the changes we have in memory and invoke stream API methods added by commit 45fdc9738b. However, sometimes if we have incomplete toast or speculative insert we spill to the disk because we can't generate the complete tuple and stream. And, as soon as we get the complete tuple we stream the transaction including the serialized changes. We can do this incremental processing thanks to having assignments (associating subxact with toplevel xacts) in WAL right away, and thanks to logging the invalidation messages at each command end. These features are added by commits 0bead9af48 and c55040ccd0 respectively. Now that we can stream in-progress transactions, the concurrent aborts may cause failures when the output plugin consults catalogs (both system and user-defined). We handle such failures by returning ERRCODE_TRANSACTION_ROLLBACK sqlerrcode from system table scan APIs to the backend or WALSender decoding a specific uncommitted transaction. The decoding logic on the receipt of such a sqlerrcode aborts the decoding of the current transaction and continue with the decoding of other transactions. We have ReorderBufferTXN pointer in each ReorderBufferChange by which we know which xact it belongs to. The output plugin can use this to decide which changes to discard in case of stream_abort_cb (e.g. when a subxact gets discarded). We also provide a new option via SQL APIs to fetch the changes being streamed. Author: Dilip Kumar, Tomas Vondra, Amit Kapila, Nikhil Sontakke Reviewed-by: Amit Kapila, Kuntal Ghosh, Ajin Cherian Tested-by: Neha Sharma, Mahendra Singh Thalor and Ajin Cherian Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
* Invent "amadjustmembers" AM method for validating opclass members.Tom Lane2020-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | This allows AM-specific knowledge to be applied during creation of pg_amop and pg_amproc entries. Specifically, the AM knows better than core code which entries to consider as required or optional. Giving the latter entries the appropriate sort of dependency allows them to be dropped without taking out the whole opclass or opfamily; which is something we'd like to have to correct obsolescent entries in extensions. This callback also opens the door to performing AM-specific validity checks during opclass creation, rather than hoping than an opclass developer will remember to test with "amvalidate". For the most part I've not actually added any such checks yet; that can happen in a follow-on patch. (Note that we shouldn't remove any tests from "amvalidate", as those are still needed to cross-check manually constructed entries in the initdb data. So adding tests to "amadjustmembers" will be somewhat duplicative, but it seems like a good idea anyway.) Patch by me, reviewed by Alexander Korotkov, Hamid Akhtar, and Anastasia Lubennikova. Discussion: https://postgr.es/m/4578.1565195302@sss.pgh.pa.us
* Initial pgindent and pgperltidy run for v13.Tom Lane2020-05-14
| | | | | | | | | | | Includes some manual cleanup of places that pgindent messed up, most of which weren't per project style anyway. Notably, it seems some people didn't absorb the style rules of commit c9d297751, because there were a bunch of new occurrences of function calls with a newline just after the left paren, all with faulty expectations about how the rest of the call would get indented.
* Remove rudiments of supporting procnum == 0 from 911e702077Alexander Korotkov2020-03-30
| | | | | | Early versions of opclass options patch uses zero support procedure as opclass options procedure. This commit removes rudiments of it, which were committed in 911e702077. Also, it implements correct handling of amoptsprocnum == 0.
* Implement operator class parametersAlexander Korotkov2020-03-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PostgreSQL provides set of template index access methods, where opclasses have much freedom in the semantics of indexing. These index AMs are GiST, GIN, SP-GiST and BRIN. There opclasses define representation of keys, operations on them and supported search strategies. So, it's natural that opclasses may be faced some tradeoffs, which require user-side decision. This commit implements opclass parameters allowing users to set some values, which tell opclass how to index the particular dataset. This commit doesn't introduce new storage in system catalog. Instead it uses pg_attribute.attoptions, which is used for table column storage options but unused for index attributes. In order to evade changing signature of each opclass support function, we implement unified way to pass options to opclass support functions. Options are set to fn_expr as the constant bytea expression. It's possible due to the fact that opclass support functions are executed outside of expressions, so fn_expr is unused for them. This commit comes with some examples of opclass options usage. We parametrize signature length in GiST. That applies to multiple opclasses: tsvector_ops, gist__intbig_ops, gist_ltree_ops, gist__ltree_ops, gist_trgm_ops and gist_hstore_ops. Also we parametrize maximum number of integer ranges for gist__int_ops. However, the main future usage of this feature is expected to be json, where users would be able to specify which way to index particular json parts. Catversion is bumped. Discussion: https://postgr.es/m/d22c3a18-31c7-1879-fc11-4c1ce2f5e5af%40postgrespro.ru Author: Nikita Glukhov, revised by me Reviwed-by: Nikolay Shaplov, Robert Haas, Tom Lane, Tomas Vondra, Alvaro Herrera
* Add deduplication to nbtree.Peter Geoghegan2020-02-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Deduplication reduces the storage overhead of duplicates in indexes that use the standard nbtree index access method. The deduplication process is applied lazily, after the point where opportunistic deletion of LP_DEAD-marked index tuples occurs. Deduplication is only applied at the point where a leaf page split would otherwise be required. New posting list tuples are formed by merging together existing duplicate tuples. The physical representation of the items on an nbtree leaf page is made more space efficient by deduplication, but the logical contents of the page are not changed. Even unique indexes make use of deduplication as a way of controlling bloat from duplicates whose TIDs point to different versions of the same logical table row. The lazy approach taken by nbtree has significant advantages over a GIN style eager approach. Most individual inserts of index tuples have exactly the same overhead as before. The extra overhead of deduplication is amortized across insertions, just like the overhead of page splits. The key space of indexes works in the same way as it has since commit dd299df8 (the commit that made heap TID a tiebreaker column). Testing has shown that nbtree deduplication can generally make indexes with about 10 or 15 tuples for each distinct key value about 2.5X - 4X smaller, even with single column integer indexes (e.g., an index on a referencing column that accompanies a foreign key). The final size of single column nbtree indexes comes close to the final size of a similar contrib/btree_gin index, at least in cases where GIN's posting list compression isn't very effective. This can significantly improve transaction throughput, and significantly reduce the cost of vacuuming indexes. A new index storage parameter (deduplicate_items) controls the use of deduplication. The default setting is 'on', so all new B-Tree indexes automatically use deduplication where possible. This decision will be reviewed at the end of the Postgres 13 beta period. There is a regression of approximately 2% of transaction throughput with synthetic workloads that consist of append-only inserts into a table with several non-unique indexes, where all indexes have few or no repeated values. The underlying issue is that cycles are wasted on unsuccessful attempts at deduplicating items in non-unique indexes. There doesn't seem to be a way around it short of disabling deduplication entirely. Note that deduplication of items in unique indexes is fairly well targeted in general, which avoids the problem there (we can use a special heuristic to trigger deduplication passes in unique indexes, since we're specifically targeting "version bloat"). Bump XLOG_PAGE_MAGIC because xl_btree_vacuum changed. No bump in BTREE_VERSION, since the representation of posting list tuples works in a way that's backwards compatible with version 4 indexes (i.e. indexes built on PostgreSQL 12). However, users must still REINDEX a pg_upgrade'd index to use deduplication, regardless of the Postgres version they've upgraded from. This is the only way to set the new nbtree metapage flag indicating that deduplication is generally safe. Author: Anastasia Lubennikova, Peter Geoghegan Reviewed-By: Peter Geoghegan, Heikki Linnakangas Discussion: https://postgr.es/m/55E4051B.7020209@postgrespro.ru https://postgr.es/m/4ab6e2db-bcee-f4cf-0916-3a06e6ccbb55@postgrespro.ru
* Remove dependency on HeapTuple from predicate locking functions.Thomas Munro2020-01-28
| | | | | | | | | | | | | | | | The following changes make the predicate locking functions more generic and suitable for use by future access methods: - PredicateLockTuple() is renamed to PredicateLockTID(). It takes ItemPointer and inserting transaction ID instead of HeapTuple. - CheckForSerializableConflictIn() takes blocknum instead of buffer. - CheckForSerializableConflictOut() no longer takes HeapTuple or buffer. Author: Ashwin Agrawal Reviewed-by: Andres Freund, Kuntal Ghosh, Thomas Munro Discussion: https://postgr.es/m/CALfoeiv0k3hkEb3Oqk%3DziWqtyk2Jys1UOK5hwRBNeANT_yX%2Bng%40mail.gmail.com
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Revert "Rename files and headers related to index AM"Michael Paquier2019-12-27
| | | | | | | | This follows multiple complains from Peter Geoghegan, Andres Freund and Alvaro Herrera that this issue ought to be dug more before actually happening, if it happens. Discussion: https://postgr.es/m/20191226144606.GA5659@alvherre.pgsql
* Rename files and headers related to index AMMichael Paquier2019-12-25
| | | | | | | | | | | | | | | | | | | | | The following renaming is done so as source files related to index access methods are more consistent with table access methods (the original names used for index AMs ware too generic, and could be confused as including features related to table AMs): - amapi.h -> indexam.h. - amapi.c -> indexamapi.c. Here we have an equivalent with backend/access/table/tableamapi.c. - amvalidate.c -> indexamvalidate.c. - amvalidate.h -> indexamvalidate.h. - genam.c -> indexgenam.c. - genam.h -> indexgenam.h. This has been discussed during the development of v12 when table AM was worked on, but the renaming never happened. Author: Michael Paquier Reviewed-by: Fabien Coelho, Julien Rouhaud Discussion: https://postgr.es/m/20191223053434.GF34339@paquier.xyz
* Remove configure --disable-float4-byvalPeter Eisentraut2019-11-21
| | | | | | | | | | | This build option was only useful to maintain compatibility for version-0 functions, but those are no longer supported, so this option can be removed. float4 is now always pass-by-value; the pass-by-reference code path is completely removed. Discussion: https://www.postgresql.org/message-id/flat/f3e1e576-2749-bbd7-2d57-3f9dcf75255a@2ndquadrant.com
* Split all OBJS style lines in makefiles into one-line-per-entry style.Andres Freund2019-11-05
| | | | | | | | | | | | | | | When maintaining or merging patches, one of the most common sources for conflicts are the list of objects in makefiles. Especially when the split across lines has been changed on both sides, which is somewhat common due to attempting to stay below 80 columns, those conflicts are unnecessarily laborious to resolve. By splitting, and alphabetically sorting, OBJS style lines into one object per line, conflicts should be less frequent, and easier to resolve when they still occur. Author: Andres Freund Discussion: https://postgr.es/m/20191029200901.vww4idgcxv74cwes@alap3.anarazel.de
* Fix freeing old values in index_store_float8_orderby_distances()Alexander Korotkov2019-09-20
| | | | | | | | | | | | | | | 6cae9d2c10 has added an error in freeing old values in index_store_float8_orderby_distances() function. It looks for old value in scan->xs_orderbynulls[i] after setting a new value there. This commit fixes that. Also it removes short-circuit in handling distances == NULL situation. Now distances == NULL will be treated the same way as array with all null distances. That is, previous values will be freed if any. Reported-by: Tom Lane, Nikita Glukhov Discussion: https://postgr.es/m/CAPpHfdu2wcoAVAm3Ek66rP%3Duo_C-D84%2B%2Buf1VEcbyi_caBXWCA%40mail.gmail.com Discussion: https://postgr.es/m/426580d3-a668-b9d1-7b8e-f74d1a6524e0%40postgrespro.ru Backpatch-through: 12
* Improve handling of NULLs in KNN-GiST and KNN-SP-GiSTAlexander Korotkov2019-09-19
| | | | | | | | | | | | | | | | | | | | | This commit improves subject in two ways: * It removes ugliness of 02f90879e7, which stores distance values and null flags in two separate arrays after GISTSearchItem struct. Instead we pack both distance value and null flag in IndexOrderByDistance struct. Alignment overhead should be negligible, because we typically deal with at most few "col op const" expressions in ORDER BY clause. * It fixes handling of "col op NULL" expression in KNN-SP-GiST. Now, these expression are not passed to support functions, which can't deal with them. Instead, NULL result is implicitly assumed. It future we may decide to teach support functions to deal with NULL arguments, but current solution is bugfix suitable for backpatch. Reported-by: Nikita Glukhov Discussion: https://postgr.es/m/826f57ee-afc7-8977-c44c-6111d18b02ec%40postgrespro.ru Author: Nikita Glukhov Reviewed-by: Alexander Korotkov Backpatch-through: 9.4
* Fix handling of NULL distances in KNN-GiSTAlexander Korotkov2019-09-08
| | | | | | | | | | | | | | In order to implement NULL LAST semantic GiST previously assumed distance to the NULL value to be Inf. However, our distance functions can return Inf and NaN for non-null values. In such cases, NULL LAST semantic appears to be broken. This commit fixes that by introducing separate array of null flags for distances. Backpatch to all supported versions. Discussion: https://postgr.es/m/CAPpHfdsNvNdA0DBS%2BwMpFrgwT6C3-q50sFVGLSiuWnV3FqOJuQ%40mail.gmail.com Author: Alexander Korotkov Backpatch-through: 9.4
* Fix inconsistencies and typos in the treeMichael Paquier2019-07-22
| | | | | | | | This is numbered take 7, and addresses a set of issues with code comments, variable names and unreferenced variables. Author: Alexander Lakhin Discussion: https://postgr.es/m/dff75442-2468-f74f-568c-6006e141062f@gmail.com