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* Consolidate nbtree VACUUM metapage routines.Peter Geoghegan2021-03-12
| | | | | | | | | | | Simplify _bt_vacuum_needs_cleanup() functions's signature (it only needs a single 'rel' argument now), and move it next to its sibling function in nbtpage.c. I believe that _bt_vacuum_needs_cleanup() was originally located in nbtree.c due to an include dependency issue. That's no longer an issue. Follow-up to commit 9f3665fb.
* Forbid marking an identity column as nullable.Tom Lane2021-03-12
| | | | | | | | | | | | | | | GENERATED ALWAYS AS IDENTITY implies NOT NULL, but the code failed to complain if you overrode that with "GENERATED ALWAYS AS IDENTITY NULL". One might think the old behavior was a feature, but it was inconsistent because the outcome varied depending on the order of the clauses, so it seems to have been just an oversight. Per bug #16913 from Pavel Boev. Back-patch to v10 where identity columns were introduced. Vik Fearing (minor tweaks by me) Discussion: https://postgr.es/m/16913-3b5198410f67d8c6@postgresql.org
* Specialize checkpointer sort functions.Thomas Munro2021-03-12
| | | | | | | | | When sorting a potentially large number of dirty buffers, the checkpointer can benefit from a faster sort routine. One reported improvement on a large buffer pool system was 1.4s -> 0.6s. Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
* Fix size overflow in calculation introduced by commits d6ad34f3 and bea449c6.Amit Kapila2021-03-12
| | | | | | | Reported-by: Thomas Munro Author: Takayuki Tsunakawa Reviewed-by: Kyotaro Horiguchi Discussion: https://postgr.es/m/CA+hUKG+oPoFizjABt=GXZWTEHx3oev5rAe2scjW2r6F1rguo5w@mail.gmail.com
* Fix use of relcache TriggerDesc field introduced by commit 05c8482f7f.Amit Kapila2021-03-12
| | | | | | | | | | | The commit added code which used a relcache TriggerDesc field across another cache access, which it shouldn't because the relcache doesn't guarantee it won't get moved. Diagnosed-by: Tom Lane Author: Greg Nancarrow Reviewed-by: Hou Zhijie, Amit Kapila Discussion: https://postgr.es/m/2309260.1615485644@sss.pgh.pa.us
* Poll postmaster less frequently in recovery.Thomas Munro2021-03-12
| | | | | | | | | | | | | | | | Since commits 9f095299 and f98b8476 we don't poll the postmaster pipe at all during crash recovery on Linux and FreeBSD, but on other operating systems we were still doing it for every WAL record. Do it less frequently on operating systems where system calls are required, at the cost of delaying exit a bit after postmaster death. This avoids expensive system calls reported to slow down CPU-bound recovery by as much as 10-30%. Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com Discussion: https://postgr.es/m/7261eb39-0369-f2f4-1bb5-62f3b6083b5e@iki.fi
* Add condition variable for walreceiver shutdown.Thomas Munro2021-03-12
| | | | | | | Use this new CV to wait for walreceiver shutdown without a sleep/poll loop, while also benefiting from standard postmaster death handling. Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com
* Add condition variable for recovery resume.Thomas Munro2021-03-12
| | | | | | | | | Replace a sleep loop with a CV, to get a fast reaction time when recovery is resumed or the postmaster exits via standard infrastructure. Unfortunately we still need to wake up every second to perform extra polling during the recovery pause loop. Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com
* Send statistics collected during shutdown checkpoint to the stats collector.Fujii Masao2021-03-12
| | | | | | | | | | | | | | When shutdown is requested, checkpointer performs checkpoint or restartpoint, and updates the statistics, before it exits. But previously checkpointer didn't send those statistics to the stats collector. Shutdown checkpoint and restartpoint are treated as requested ones instead of scheduled ones, so the number of them are counted in pg_stat_bgwriter.checkpoints_req column. Author: Masahiro Ikeda Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
* Force to send remaining WAL stats to the stats collector at walwriter exit.Fujii Masao2021-03-12
| | | | | | | | | | | | | | | | | | | In walwriter's main loop, WAL stats message is only sent if enough time has passed since last one was sent to reach PGSTAT_STAT_INTERVAL msecs. This is necessary to avoid overloading to the stats collector. But this can cause recent WAL stats to be unsent when walwriter exits. To ensure that all the WAL stats are sent, this commit makes walwriter force to send remaining WAL stats to the collector when it exits because of shutdown request. Note that those remaining WAL stats can still be unsent when walwriter exits with non-zero exit code (e.g., FATAL error). This is OK because that walwriter exit leads to server crash and subsequent recovery discards all the stats. So there is no need to send remaining stats in that case. Author: Masahiro Ikeda Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
* Minor modernization for README.barrier.Thomas Munro2021-03-12
| | | | | Itanium is very uncommon and being discontinued. ARM is everywhere. Prefer ARM as an example of an architecture with weak memory ordering.
* Save a few cycles during nbtree VACUUM.Peter Geoghegan2021-03-11
| | | | | | | | | | | Avoid calling RelationGetNumberOfBlocks() unnecessarily in the common case where there are no deleted but not yet recycled pages to recycle during a cleanup-only nbtree VACUUM operation. Follow-up to commit e5d8a999, which (among other things) taught the "skip full scan" nbtree VACUUM mechanism to only trigger a full index scan when the absolute number of deleted pages in the index is considered excessive.
* Add back vacuum_cleanup_index_scale_factor parameter.Peter Geoghegan2021-03-11
| | | | | | | | | | | | | | | | | Commit 9f3665fb removed the vacuum_cleanup_index_scale_factor storage parameter. However, that creates dump/reload hazards when moving across major versions. Add back the vacuum_cleanup_index_scale_factor parameter (though not the GUC of the same name) purely to avoid problems when using tools like pg_upgrade. The parameter remains disabled and undocumented. No backpatch to Postgres 13, since vacuum_cleanup_index_scale_factor was only disabled by REL_13_STABLE's version of master branch commit 9f3665fb in the first place -- the parameter already looks like this on REL_13_STABLE. Discussion: https://postgr.es/m/YEm/a3Ko3nKnBuVq@paquier.xyz
* Be clear about whether a recovery pause has taken effect.Robert Haas2021-03-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, the code and documentation seem to have essentially assumed than a call to pg_wal_replay_pause() would take place immediately, but that's not the case, because we only check for a pause in certain places. This means that a tool that uses this function and then wants to do something else afterward that is dependent on the pause having taken effect doesn't know how long it needs to wait to be sure that no more WAL is going to be replayed. To avoid that, add a new function pg_get_wal_replay_pause_state() which returns either 'not paused', 'paused requested', or 'paused'. After calling pg_wal_replay_pause() the status will immediate change from 'not paused' to 'pause requested'; when the startup process has noticed this, the status will change to 'pause'. For backward compatibility, pg_is_wal_replay_paused() still exists and returns the same thing as before: true if a pause has been requested, whether or not it has taken effect yet; and false if not. The documentation is updated to clarify. To improve the changes that a pause request is quickly confirmed effective, adjust things so that WaitForWALToBecomeAvailable will swiftly reach a call to recoveryPausesHere() when a pause request is made. Dilip Kumar, reviewed by Simon Riggs, Kyotaro Horiguchi, Yugo Nagata, Masahiko Sawada, and Bharath Rupireddy. Discussion: http://postgr.es/m/CAFiTN-vcLLWEm8Zr%3DYK83rgYrT9pbC8VJCfa1kY9vL3AUPfu6g%40mail.gmail.com
* VACUUM ANALYZE: Always update pg_class.reltuples.Peter Geoghegan2021-03-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vacuumlazy.c sometimes fails to update pg_class entries for each index (to ensure that pg_class.reltuples is current), even though analyze.c assumed that that must have happened during VACUUM ANALYZE. There are at least a couple of reasons for this. For example, vacuumlazy.c could fail to update pg_class when the index AM indicated that its statistics are merely an estimate, per the contract for amvacuumcleanup() routines established by commit e57345975cf back in 2006. Stop assuming that pg_class must have been updated with accurate statistics within VACUUM ANALYZE -- update pg_class for indexes at the same time as the table relation in all cases. That way VACUUM ANALYZE will never fail to keep pg_class.reltuples reasonably accurate. The only downside of this approach (compared to the old approach) is that it might inaccurately set pg_class.reltuples for indexes whose heap relation ends up with the same inaccurate value anyway. This doesn't seem too bad. We already consistently called vac_update_relstats() (to update pg_class) for the heap/table relation twice during any VACUUM ANALYZE -- once in vacuumlazy.c, and once in analyze.c. We now make sure that we call vac_update_relstats() at least once (though often twice) for each index. This is follow up work to commit 9f3665fb, which dealt with issues in btvacuumcleanup(). Technically this fixes an unrelated issue, though. btvacuumcleanup() no longer provides an accurate num_index_tuples value following commit 9f3665fb (when there was no btbulkdelete() call during the VACUUM operation in question), but hashvacuumcleanup() has worked in the same way for many years now. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAH2-WzknxdComjhqo4SUxVFk_Q1171GJO2ZgHZ1Y6pion6u8rA@mail.gmail.com Backpatch: 13-, just like commit 9f3665fb.
* Don't consider newly inserted tuples in nbtree VACUUM.Peter Geoghegan2021-03-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the entire idea of "stale stats" within nbtree VACUUM (stop caring about stats involving the number of inserted tuples). Also remove the vacuum_cleanup_index_scale_factor GUC/param on the master branch (though just disable them on postgres 13). The vacuum_cleanup_index_scale_factor/stats interface made the nbtree AM partially responsible for deciding when pg_class.reltuples stats needed to be updated. This seems contrary to the spirit of the index AM API, though -- it is not actually necessary for an index AM's bulk delete and cleanup callbacks to provide accurate stats when it happens to be inconvenient. The core code owns that. (Index AMs have the authority to perform or not perform certain kinds of deferred cleanup based on their own considerations, such as page deletion and recycling, but that has little to do with pg_class.reltuples/num_index_tuples.) This issue was fairly harmless until the introduction of the autovacuum_vacuum_insert_threshold feature by commit b07642db, which had an undesirable interaction with the vacuum_cleanup_index_scale_factor mechanism: it made insert-driven autovacuums perform full index scans, even though there is no real benefit to doing so. This has been tied to a regression with an append-only insert benchmark [1]. Also have remaining cases that perform a full scan of an index during a cleanup-only nbtree VACUUM indicate that the final tuple count is only an estimate. This prevents vacuumlazy.c from setting the index's pg_class.reltuples in those cases (it will now only update pg_class when vacuumlazy.c had TIDs for nbtree to bulk delete). This arguably fixes an oversight in deduplication-related bugfix commit 48e12913. [1] https://smalldatum.blogspot.com/2021/01/insert-benchmark-postgres-is-still.html Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAD21AoA4WHthN5uU6+WScZ7+J_RcEjmcuH94qcoUPuB42ShXzg@mail.gmail.com Backpatch: 13-, where autovacuum_vacuum_insert_threshold was added.
* C comments: improve description of GiST NSN and GistBuildLSNBruce Momjian2021-03-10
| | | | | | | GiST indexes are complex, so adding more details in the code might help someone. Discussion: https://postgr.es/m/20210302164021.GA364@momjian.us
* Replace buffer I/O locks with condition variables.Thomas Munro2021-03-11
| | | | | | | | | | | | | | | | | | | 1. Backends waiting for buffer I/O are now interruptible. 2. If something goes wrong in a backend that is currently performing I/O, waiting backends no longer wake up until that backend reaches AbortBufferIO() and broadcasts on the CV. Previously, any waiters would wake up (because the I/O lock was automatically released) and then busy-loop until AbortBufferIO() cleared BM_IO_IN_PROGRESS. 3. LWLockMinimallyPadded is removed, as it would now be unused. Author: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Thomas Munro <thomas.munro@gmail.com> Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (earlier version, 2016) Discussion: https://postgr.es/m/CA%2BhUKGJ8nBFrjLuCTuqKN0pd2PQOwj9b_jnsiGFFMDvUxahj_A%40mail.gmail.com Discussion: https://postgr.es/m/CA+Tgmoaj2aPti0yho7FeEf2qt-JgQPRWb0gci_o1Hfr=C56Xng@mail.gmail.com
* Avoid creating duplicate cached plans for inherited FK constraints.Tom Lane2021-03-10
| | | | | | | | | | | | | | | | | When a foreign key constraint is applied to a partitioned table, each leaf partition inherits a similar FK constraint. We were processing all of those constraints independently, meaning that in large partitioning trees we'd build up large collections of cached FK-checking query plans. However, in all cases but one, the generated queries are actually identical for all members of the inheritance tree (because, in most cases, the query only mentions the topmost table of the other side of the FK relationship). So we can share a single cached plan among all the partitions, saving memory, not to mention time to build and maintain the cached plans. Keisuke Kuroda and Amit Langote Discussion: https://postgr.es/m/cab4b85d-9292-967d-adf2-be0d803c3e23@nttcom.co.jp_1
* Add bound check before bsearch() for performancePeter Eisentraut2021-03-10
| | | | | | | | | | | | | | | In the current lazy vacuum implementation, some index AMs such as btree indexes call lazy_tid_reaped() for each index tuple during ambulkdelete to check if the index tuple points to the (collected) garbage tuple. In that function, we simply call bsearch(), but we should be able to know the result without bsearch() if the index tuple points to the heap tuple that is out of range of the collected garbage tuples. Therefore, add a simple bound check before resorting to bsearch(). Testing has shown that this can give significant performance benefits. Author: Masahiko Sawada <masahiko.sawada@2ndquadrant.com> Discussion: https://www.postgresql.org/message-id/flat/CA+fd4k76j8jKzJzcx8UqEugvayaMSnQz0iLUt_XgBp-_-bd22A@mail.gmail.com
* Small debug message tweakPeter Eisentraut2021-03-10
| | | | This makes the wording of the delete case match the update case.
* Fix valgrind issue in commit 05c8482f7f.Amit Kapila2021-03-10
| | | | | | | | | | Initialize other newly added variables in max_parallel_hazard_context via is_parallel_safe() because we don't check the parallel-safety of target relations in that function. Reported-by: Tom Lane as per buildfarm Author: Amit Kapila Discussion: https://postgr.es/m/2060179.1615347455@sss.pgh.pa.us
* Enable parallel SELECT for "INSERT INTO ... SELECT ...".Amit Kapila2021-03-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Parallel SELECT can't be utilized for INSERT in the following cases: - INSERT statement uses the ON CONFLICT DO UPDATE clause - Target table has a parallel-unsafe: trigger, index expression or predicate, column default expression or check constraint - Target table has a parallel-unsafe domain constraint on any column - Target table is a partitioned table with a parallel-unsafe partition key expression or support function The planner is updated to perform additional parallel-safety checks for the cases listed above, for determining whether it is safe to run INSERT in parallel-mode with an underlying parallel SELECT. The planner will consider using parallel SELECT for "INSERT INTO ... SELECT ...", provided nothing unsafe is found from the additional parallel-safety checks, or from the existing parallel-safety checks for SELECT. While checking parallel-safety, we need to check it for all the partitions on the table which can be costly especially when we decide not to use a parallel plan. So, in a separate patch, we will introduce a GUC and or a reloption to enable/disable parallelism for Insert statements. Prior to entering parallel-mode for the execution of INSERT with parallel SELECT, a TransactionId is acquired and assigned to the current transaction state. This is necessary to prevent the INSERT from attempting to assign the TransactionId whilst in parallel-mode, which is not allowed. This approach has a disadvantage in that if the underlying SELECT does not return any rows, then the TransactionId is not used, however that shouldn't happen in practice in many cases. Author: Greg Nancarrow, Amit Langote, Amit Kapila Reviewed-by: Amit Langote, Hou Zhijie, Takayuki Tsunakawa, Antonin Houska, Bharath Rupireddy, Dilip Kumar, Vignesh C, Zhihong Yu, Amit Kapila Tested-by: Tang, Haiying Discussion: https://postgr.es/m/CAJcOf-cXnB5cnMKqWEp2E2z7Mvcd04iLVmV=qpFJrR3AcrTS3g@mail.gmail.com Discussion: https://postgr.es/m/CAJcOf-fAdj=nDKMsRhQzndm-O13NY4dL6xGcEvdX5Xvbbi0V7g@mail.gmail.com
* Track total amounts of times spent writing and syncing WAL data to disk.Fujii Masao2021-03-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds new GUC track_wal_io_timing. When this is enabled, the total amounts of time XLogWrite writes and issue_xlog_fsync syncs WAL data to disk are counted in pg_stat_wal. This information would be useful to check how much WAL write and sync affect the performance. Enabling track_wal_io_timing will make the server query the operating system for the current time every time WAL is written or synced, which may cause significant overhead on some platforms. To avoid such additional overhead in the server with track_io_timing enabled, this commit introduces track_wal_io_timing as a separate parameter from track_io_timing. Note that WAL write and sync activity by walreceiver has not been tracked yet. This commit makes the server also track the numbers of times XLogWrite writes and issue_xlog_fsync syncs WAL data to disk, in pg_stat_wal, regardless of the setting of track_wal_io_timing. This counters can be used to calculate the WAL write and sync time per request, for example. Bump PGSTAT_FILE_FORMAT_ID. Bump catalog version. Author: Masahiro Ikeda Reviewed-By: Japin Li, Hayato Kuroda, Masahiko Sawada, David Johnston, Fujii Masao Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
* Add support for more progress reporting in COPYMichael Paquier2021-03-09
| | | | | | | | | | | | | | | | | The command (TO or FROM), its type (file, pipe, program or callback), and the number of tuples excluded by a WHERE clause in COPY FROM are added to the progress reporting already available. The column "lines_processed" is renamed to "tuples_processed" to disambiguate the meaning of this column in the cases of CSV and BINARY COPY and to be more consistent with the other catalog progress views. Bump catalog version, again. Author: Matthias van de Meent Reviewed-by: Michael Paquier, Justin Pryzby, Bharath Rupireddy, Josef Šimánek, Tomas Vondra Discussion: https://postgr.es/m/CAEze2WiOcgdH4aQA8NtZq-4dgvnJzp8PohdeKchPkhMY-jWZXA@mail.gmail.com
* Remove support for SSL compressionMichael Paquier2021-03-09
| | | | | | | | | | | | | | | | | | | | | | | | | | PostgreSQL disabled compression as of e3bdb2d and the documentation recommends against using it since. Additionally, SSL compression has been disabled in OpenSSL since version 1.1.0, and was disabled in many distributions long before that. The most recent TLS version, TLSv1.3, disallows compression at the protocol level. This commit removes the feature itself, removing support for the libpq parameter sslcompression (parameter still listed for compatibility reasons with existing connection strings, just ignored), and removes the equivalent field in pg_stat_ssl and de facto PgBackendSSLStatus. Note that, on top of removing the ability to activate compression by configuration, compression is actively disabled in both frontend and backend to avoid overrides from local configurations. A TAP test is added for deprecated SSL parameters to check after backwards compatibility. Bump catalog version. Author: Daniel Gustafsson Reviewed-by: Peter Eisentraut, Magnus Hagander, Michael Paquier Discussion: https://postgr.es/m/7E384D48-11C5-441B-9EC3-F7DB1F8518F6@yesql.se
* Complain if a function-in-FROM returns a set when it shouldn't.Tom Lane2021-03-08
| | | | | | | | | | | | | | | Throw a "function protocol violation" error if a function in FROM tries to return a set though it wasn't marked proretset. Although such cases work at the moment, it doesn't seem like something we want to guarantee will keep working. Besides, there are other negative consequences of not setting the proretset flag, such as potentially bad plans. No back-patch, since if there is any third-party code violating this expectation, people wouldn't appreciate us breaking it in a minor release. Discussion: https://postgr.es/m/1636062.1615141782@sss.pgh.pa.us
* Validate the OID argument of pg_import_system_collations().Tom Lane2021-03-08
| | | | | | | | | | | | | "SELECT pg_import_system_collations(0)" caused an assertion failure. With a random nonzero argument --- or indeed with zero, in non-assert builds --- it would happily make pg_collation entries with garbage values of collnamespace. These are harmless as far as I can tell (unless maybe the OID happens to become used for a schema, later on?). In any case this isn't a security issue, since the function is superuser-only. But it seems like a gotcha for unwary DBAs, so let's add a check that the given OID belongs to some schema. Back-patch to v10 where this function was introduced.
* Further tweak memory management for regex DFAs.Tom Lane2021-03-08
| | | | | | | | | | | | | | | | | | | | Coverity is still unhappy after commit 190c79884, and after looking closer I think it might be onto something. The callers of newdfa() typically drop out if v->err has been set nonzero, which newdfa() is faithfully doing if it fails. However, what if v->err was already nonzero before we entered newdfa()? Then newdfa() could succeed and the caller would promptly leak its result. I don't think this scenario can actually happen, but the predicate "v->err is always zero when newdfa() is called" seems difficult to be entirely sure of; there's a good deal of code that potentially could get that wrong. It seems better to adjust the callers to directly check for a null result instead of relying on ISERR() tests. This is slightly cheaper than the previous coding anyway. Lacking evidence that there's any real bug, no back-patch.
* Track replication origin progress for rollbacks.Amit Kapila2021-03-08
| | | | | | | | | | | | | | | | Commit 1eb6d6527a allowed to track replica origin replay progress for 2PC but it was not complete. It misses to properly track the progress for rollback prepared especially it missed updating the code for recovery. Additionally, we need to allow tracking it on subscriber nodes where wal_level might not be logical. It is required to track decoding of 2PC which is committed in PG14 (a271a1b50e) and also nobody complained about this till now so not backpatching it. Author: Amit Kapila Reviewed-by: Michael Paquier and Ajin Cherian Discussion: https://postgr.es/m/CAA4eK1L-kHmMnSdrRW6UhRbCjR7cgh04c+6psY15qzT6ktcd+g@mail.gmail.com
* Remove server and libpq support for old FE/BE protocol version 2.Heikki Linnakangas2021-03-04
| | | | | | | | | | | | | | | | | Protocol version 3 was introduced in PostgreSQL 7.4. There shouldn't be many clients or servers left out there without version 3 support. But as a courtesy, I kept just enough of the old protocol support that we can still send the "unsupported protocol version" error in v2 format, so that old clients can display the message properly. Likewise, libpq still understands v2 ErrorResponse messages when establishing a connection. The impetus to do this now is that I'm working on a patch to COPY FROM, to always prefetch some data. We cannot do that safely with the old protocol, because it requires parsing the input one byte at a time to detect the end-of-copy marker. Reviewed-by: Tom Lane, Alvaro Herrera, John Naylor Discussion: https://www.postgresql.org/message-id/9ec25819-0a8a-d51a-17dc-4150bb3cca3b%40iki.fi
* Add trim_array() function.Tom Lane2021-03-03
| | | | | | | | | | This has been in the SQL spec since 2008. It's a pretty thin wrapper around the array slice functionality, but the spec says we should have it, so here it is. Vik Fearing, reviewed by Dian Fay Discussion: https://postgr.es/m/fc92ce17-9655-8ff1-c62a-4dc4c8ccd815@postgresfriends.org
* Some copy-editing of GUC descriptionsPeter Eisentraut2021-03-03
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* Use sort_template.h for qsort_tuple() and qsort_ssup().Thomas Munro2021-03-03
| | | | | | | | Replace the Perl code previously used to generate specialized sort functions with sort_template.h. Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
* Add option to enable two_phase commits via pg_create_logical_replication_slot.Amit Kapila2021-03-03
| | | | | | | | | | | | | | | | | | | | Commit 0aa8a01d04 extends the output plugin API to allow decoding of prepared xacts and allowed the user to enable/disable the two-phase option via pg_logical_slot_get_changes(). This can lead to a problem such that the first time when it gets changes via pg_logical_slot_get_changes() without two_phase option enabled it will not get the prepared even though prepare is after consistent snapshot. Now next time during getting changes, if the two_phase option is enabled it can skip prepare because by that time start decoding point has been moved. So the user will only get commit prepared. Allow to enable/disable this option at the create slot time and default will be false. It will break the existing slots which is fine in a major release. Author: Ajin Cherian Reviewed-by: Amit Kapila and Vignesh C Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
* nbtree page deletion: Add leaftopparent assertion.Peter Geoghegan2021-03-02
| | | | | | Add documenting assertion. This makes it easier to follow how we maintain the top parent link in target subtree's half-dead/leaf level page.
* Fix nbtree page deletion error messages.Peter Geoghegan2021-03-02
| | | | | | | | | | | | Adjust some "can't happen" error messages that assumed that the page deletion target page must be a half-dead page. This assumption was wrong in the case of an internal target page. Simply refer to these pages as the target page instead. Internal pages are never marked half-dead. There is exactly one half-dead page for each subtree undergoing deletion. The half-dead page is also the target subtree's leaf-level page. This has been the case since commit efada2b8, which totally overhauled nbtree page deletion.
* Mark default_transaction_read_only as GUC_REPORT.Tom Lane2021-03-02
| | | | | | | | | | | | | | This allows clients to find out the setting at connection time without having to expend a query round trip to do so; which is helpful when trying to identify read/write servers. (One must also look at in_hot_standby, but that's already GUC_REPORT, cf bf8a662c9.) Modifying libpq to make use of this will come soon, but I felt it cleaner to push the server change separately. Haribabu Kommi, Greg Nancarrow, Vignesh C; reviewed at various times by Laurenz Albe, Takayuki Tsunakawa, Peter Smith. Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com
* Suppress unnecessary regex subre nodes in a couple more cases.Tom Lane2021-03-02
| | | | | | | | | | | | | | | This extends the changes made in commit cebc1d34e, teaching parseqatom() to generate fewer or cheaper subre nodes in some edge cases. The case of interest here is a quantified atom that is "messy" only because it has greediness opposite to what preceded it (whereas captures and backrefs are intrinsically messy). In this case we don't need an iteration node, since we don't care where the sub-matches of the quantifier are; and we might also not need a second concatenation node. This seems of only marginal real-world use according to my testing, but I wanted to get it in before wrapping up this series of regex performance fixes. Discussion: https://postgr.es/m/1340281.1613018383@sss.pgh.pa.us
* Improve performance of regular expression back-references.Tom Lane2021-03-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some cases, at the time that we're doing an NFA-based precheck of whether a backref subexpression can match at a particular place in the string, we already know which substring the referenced subexpression matched. If so, we might as well forget about the NFA and just compare the substring; this is faster and it gives an exact rather than approximate answer. In general, this optimization can help while we are prechecking within the second child expression of a concat node, while the capture was within the first child expression; then the substring was saved during cdissect() of the first child and will be available to NFA checks done while cdissect() recurses into the second child. It can help quite a lot if the tree looks like concat / \ capture concat / \ expensive stuff backref as we will be able to avoid recursively dissecting the "expensive stuff" before discovering that the backref isn't satisfied with a particular midpoint that the lower concat node is testing. This doesn't help if the concat tree is left-deep, as the capture node won't get set soon enough (and it's hard to fix that without changing the engine's match behavior). Fortunately, right-deep concat trees are the common case. Patch by me, reviewed by Joel Jacobson Discussion: https://postgr.es/m/661609.1614560029@sss.pgh.pa.us
* Fix semantics of regular expression back-references.Tom Lane2021-03-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | POSIX defines the behavior of back-references thus: The back-reference expression '\n' shall match the same (possibly empty) string of characters as was matched by a subexpression enclosed between "\(" and "\)" preceding the '\n'. As far as I can see, the back-reference is supposed to consider only the data characters matched by the referenced subexpression. However, because our engine copies the NFA constructed from the referenced subexpression, it effectively enforces any constraints therein, too. As an example, '(^.)\1' ought to match 'xx', or any other string starting with two occurrences of the same character; but in our code it does not, and indeed can't match anything, because the '^' anchor constraint is included in the backref's copied NFA. If POSIX intended that, you'd think they'd mention it. Perl for one doesn't act that way, so it's hard to conclude that this isn't a bug. Fix by modifying the backref's NFA immediately after it's copied from the reference, replacing all constraint arcs by EMPTY arcs so that the constraints are treated as automatically satisfied. This still allows us to enforce matching rules that depend only on the data characters; for example, in '(^\d+).*\1' the NFA matching step will still know that the backref can only match strings of digits. Perhaps surprisingly, this change does not affect the results of any of a rather large corpus of real-world regexes. Nonetheless, I would not consider back-patching it, since it's a clear compatibility break. Patch by me, reviewed by Joel Jacobson Discussion: https://postgr.es/m/661609.1614560029@sss.pgh.pa.us
* Simplify code to switch pg_class.relrowsecurity in tablecmds.cMichael Paquier2021-03-02
| | | | | | | | | | The same code pattern was repeated twice to enable or disable ROW LEVEL SECURITY with an ALTER TABLE command. This makes the code slightly cleaner. Author: Justin Pryzby Reviewed-by: Zhihong Yu Discussion: https://postgr.es/m/20210228211854.GC20769@telsasoft.com
* Improve reporting for syntax errors in multi-line JSON data.Tom Lane2021-03-01
| | | | | | | | | | | Point to the specific line where the error was detected; the previous code tended to include several preceding lines as well. Avoid re-scanning the entire input to recompute which line that was. Simplify the logic a bit. Add test cases. Simon Riggs and Hamid Akhtar, reviewed by Daniel Gustafsson and myself Discussion: https://postgr.es/m/CANbhV-EPBnXm3MF_TTWBwwqgn1a1Ghmep9VHfqmNBQ8BT0f+_g@mail.gmail.com
* Remove obsolete comment for WaitForProcSignalBarrier().Thomas Munro2021-03-02
| | | | | | Commit 814f1d8b removed the behavior described. Reported-by: Amit Kapila <amit.kapila16@gmail.com>
* Allow condition variables to be used in interrupt code.Thomas Munro2021-03-01
| | | | | | | | | | Adjust the condition variable sleep loop to work correctly when code reached by its internal CHECK_FOR_INTERRUPTS() call interacts with another condition variable. There are no such cases currently, but a proposed patch would do this. Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
* Use condition variables for ProcSignalBarriers.Thomas Munro2021-03-01
| | | | | | | Instead of a poll/sleep loop, use a condition variable for precise wake-up whenever a backend's pss_barrierGeneration advances. Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
* Avoid repeated decoding of prepared transactions after a restart.Amit Kapila2021-03-01
| | | | | | | | | | | | | | | | | | | | In commit a271a1b50e, we allowed decoding at prepare time and the prepare was decoded again if there is a restart after decoding it. It was done that way because we can't distinguish between the cases where we have not decoded the prepare because it was prior to consistent snapshot or we have decoded it earlier but restarted. To distinguish between these two cases, we have introduced an initial_consistent_point at the slot level which is an LSN at which we found a consistent point at the time of slot creation. This is also the point where we have exported a snapshot for the initial copy. So, prepare transaction prior to this point are sent along with commit prepared. This commit bumps SNAPBUILD_VERSION because of change in SnapBuild. It will break existing slots which is fine in a major release. Author: Ajin Cherian, based on idea by Andres Freund Reviewed-by: Amit Kapila and Vignesh C Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
* Use FeBeWaitSet for walsender.c.Thomas Munro2021-03-01
| | | | | | | | | | This avoids the need to set up and tear down a fresh WaitEventSet every time we need need to wait. We have to add an explicit exit on postmaster exit (FeBeWaitSet isn't set up to do that automatically), so move the code to do that into a new function to avoid repetition. Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> (earlier version) Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
* Introduce symbolic names for FeBeWaitSet positions.Thomas Munro2021-03-01
| | | | | | | | | Previously we used 0 and 1 to refer to the socket and latch in far flung parts of the tree, without any explanation. Also use PGINVALID_SOCKET rather than -1 in a couple of places that didn't already do that. Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
* Update the docs and comments for decoding of prepared xacts.Amit Kapila2021-03-01
| | | | | | | | | | | | Commit a271a1b50e introduced decoding at prepare time in ReorderBuffer. This can lead to deadlock for out-of-core logical replication solutions that uses this feature to build distributed 2PC in case such transactions lock [user] catalog tables exclusively. They need to inform users to not have locks on catalog tables (via explicit LOCK command) in such transactions. Reported-by: Andres Freund Discussion: https://postgr.es/m/20210222222847.tpnb6eg3yiykzpky@alap3.anarazel.de
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