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path: root/src/include/access/parallel.h
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* Rename some signal and interrupt handling functions for consistencyHeikki Linnakangas2025-03-05
| | | | | | | | | | | | | | | | | | | | | | | | The usual pattern for handling a signal is that the signal handler sets a flag and calls SetLatch(MyLatch), and CHECK_FOR_INTERRUPTS() or other code that is part of a wait loop calls another function to deal with it. The naming of the functions involved was a bit inconsistent, however. CHECK_FOR_INTERRUPTS() calls ProcessInterrupts() to do the heavy-lifting, but the analogous functions in aux processes were called HandleMainLoopInterrupts(), HandleStartupProcInterrupts(), etc. Similarly, most subroutines of ProcessInterrupts() were called Process*(), but some were called Handle*(). To make things less confusing, rename all the functions that are part of the overall signal/interrupt handling system but are not executed in a signal handler to e.g. ProcessSomething(), rather than HandleSomething(). The "Process" prefix is now consistently used in the non-signal-handler functions, and the "Handle" prefix in functions that are part of signal handlers, except for some completely unrelated functions that clearly have nothing to do with signal or interrupt handling. Reviewed-by: Nathan Bossart <nathandbossart@gmail.com> Discussion: https://www.postgresql.org/message-id/8a384b26-1499-41f6-be33-64b801fb98b8@iki.fi
* Update copyright for 2025Bruce Momjian2025-01-01
| | | | Backpatch-through: 13
* Remove unused ParallelWorkerInfo.pid fieldHeikki Linnakangas2024-03-04
| | | | | | | The pid was originally used in error context of messages propagated from parallel workers, but commit 292794f82b removed that. If the need arises in the future, you can also get the pid with "shm_mq_get_sender(pcxt->worker[i].error_mqh)->pid".
* Update copyright for 2024Bruce Momjian2024-01-03
| | | | | | | | Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
* Update copyright for 2023Bruce Momjian2023-01-02
| | | | Backpatch-through: 11
* Mark ParallelMessagePending as sig_atomic_tMichael Paquier2022-09-27
| | | | | | | | | ParallelMessagePending was previously marked as a boolean which should be fine on modern platforms, but the C standard recommends the use of sig_atomic_t for variables manipulated in signal handlers. Author: Hayato Kuroda Discussion: https://postgr.es/m/TYAPR01MB58667C15A95A234720F4F876F5529@TYAPR01MB5866.jpnprd01.prod.outlook.com
* Apply PGDLLIMPORT markings broadly.Robert Haas2022-04-08
| | | | | | | | | | | Up until now, we've had a policy of only marking certain variables in the PostgreSQL header files with PGDLLIMPORT, but now we've decided to mark them all. This means that extensions running on Windows should no longer operate at a disadvantage as compared to extensions running on Linux: if the variable is present in a header file, it should be accessible. Discussion: http://postgr.es/m/CA+TgmoYanc1_FSfimhgiWSqVyP5KKmh5NP2BWNwDhO8Pg2vGYQ@mail.gmail.com
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Allow vacuum command to process indexes in parallel.Amit Kapila2020-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | This feature allows the vacuum to leverage multiple CPUs in order to process indexes. This enables us to perform index vacuuming and index cleanup with background workers. This adds a PARALLEL option to VACUUM command where the user can specify the number of workers that can be used to perform the command which is limited by the number of indexes on a table. Specifying zero as a number of workers will disable parallelism. This option can't be used with the FULL option. Each index is processed by at most one vacuum process. Therefore parallel vacuum can be used when the table has at least two indexes. The parallel degree is either specified by the user or determined based on the number of indexes that the table has, and further limited by max_parallel_maintenance_workers. The index can participate in parallel vacuum iff it's size is greater than min_parallel_index_scan_size. Author: Masahiko Sawada and Amit Kapila Reviewed-by: Dilip Kumar, Amit Kapila, Robert Haas, Tomas Vondra, Mahendra Singh and Sergei Kornilov Tested-by: Mahendra Singh and Prabhat Sahu Discussion: https://postgr.es/m/CAD21AoDTPMgzSkV4E3SFo1CH_x50bf5PqZFQf4jmqjk-C03BWg@mail.gmail.com https://postgr.es/m/CAA4eK1J-VoR9gzS5E75pcD-OH0mEyCdp8RihcwKrcuw7J-Q0+w@mail.gmail.com
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Phase 2 pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | | Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
* Enable parallel query with SERIALIZABLE isolation.Thomas Munro2019-03-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, the SERIALIZABLE isolation level prevented parallel query from being used. Allow the two features to be used together by sharing the leader's SERIALIZABLEXACT with parallel workers. An extra per-SERIALIZABLEXACT LWLock is introduced to make it safe to share, and new logic is introduced to coordinate the early release of the SERIALIZABLEXACT required for the SXACT_FLAG_RO_SAFE optimization, as follows: The first backend to observe the SXACT_FLAG_RO_SAFE flag (set by some other transaction) will 'partially release' the SERIALIZABLEXACT, meaning that the conflicts and locks it holds are released, but the SERIALIZABLEXACT itself will remain active because other backends might still have a pointer to it. Whenever any backend notices the SXACT_FLAG_RO_SAFE flag, it clears its own MySerializableXact variable and frees local resources so that it can skip SSI checks for the rest of the transaction. In the special case of the leader process, it transfers the SERIALIZABLEXACT to a new variable SavedSerializableXact, so that it can be completely released at the end of the transaction after all workers have exited. Remove the serializable_okay flag added to CreateParallelContext() by commit 9da0cc35, because it's now redundant. Author: Thomas Munro Reviewed-by: Haribabu Kommi, Robert Haas, Masahiko Sawada, Kevin Grittner Discussion: https://postgr.es/m/CAEepm=0gXGYhtrVDWOTHS8SQQy_=S9xo+8oCxGLWZAOoeJ=yzQ@mail.gmail.com
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Support parallel btree index builds.Robert Haas2018-02-02
| | | | | | | | | | | | | | | | | | | | | | To make this work, tuplesort.c and logtape.c must also support parallelism, so this patch adds that infrastructure and then applies it to the particular case of parallel btree index builds. Testing to date shows that this can often be 2-3x faster than a serial index build. The model for deciding how many workers to use is fairly primitive at present, but it's better than not having the feature. We can refine it as we get more experience. Peter Geoghegan with some help from Rushabh Lathia. While Heikki Linnakangas is not an author of this patch, he wrote other patches without which this feature would not have been possible, and therefore the release notes should possibly credit him as an author of this feature. Reviewed by Claudio Freire, Heikki Linnakangas, Thomas Munro, Tels, Amit Kapila, me. Discussion: http://postgr.es/m/CAM3SWZQKM=Pzc=CAHzRixKjp2eO5Q0Jg1SoFQqeXFQ647JiwqQ@mail.gmail.com Discussion: http://postgr.es/m/CAH2-Wz=AxWqDoVvGU7dq856S4r6sJAj6DBn7VMtigkB33N5eyg@mail.gmail.com
* Add new function WaitForParallelWorkersToAttach.Robert Haas2018-02-02
| | | | | | | | | | | | | | | | Once this function has been called, we know that all workers have started and attached to their error queues -- so if any of them subsequently exit uncleanly, we'll be sure to throw an ERROR promptly. Otherwise, users of the ParallelContext machinery must be careful not to wait forever for a worker that has failed to start. Parallel query manages to work without needing this for reasons explained in new comments added by this patch, but it's a useful primitive for other parallel operations, such as the pending patch to make creating a btree index run in parallel. Amit Kapila, revised by me. Additional review by Peter Geoghegan. Discussion: http://postgr.es/m/CAA4eK1+e2MzyouF5bg=OtyhDSX+=Ao=3htN=T-r_6s3gCtKFiw@mail.gmail.com
* Report an ERROR if a parallel worker fails to start properly.Robert Haas2018-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 28724fd90d2f85a0573a8107b48abad062a86d83 fixed things so that if a background worker fails to start due to fork() failure or because it is terminated before startup succeeds, BGWH_STOPPED will be reported. However, that only helps if the code that uses the background worker machinery notices the change in status, and the code in parallel.c did not. To fix that, do two things. First, make sure that when a worker exits, it triggers the leader to read from error queues. That way, if a worker which has attached to an error queue exits uncleanly, the leader is sure to throw some error, either the contents of the ErrorResponse sent by the worker, or "lost connection to parallel worker" if it exited without sending one. To cover the case where the worker never starts up in the first place or exits before attaching to the error queue, the ParallelContext now keeps track of which workers have sent at least one message via the error queue. A worker which sends no messages by the time the parallel operation finishes will be checked to see whether it exited before attaching to the error queue; if so, a new error message, "parallel worker failed to initialize", will be reported. If not, we'll continue to wait until it either starts up and exits cleanly, starts up and exits uncleanly, or fails to start, and then take the appropriate action. Patch by me, reviewed by Amit Kapila. Discussion: http://postgr.es/m/CA+TgmoYnBgXgdTu6wk5YPdWhmgabYc9nY_pFLq=tB=FSLYkD8Q@mail.gmail.com
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Mark a few parallelism-related variables with PGDLLIMPORT.Robert Haas2017-12-19
| | | | Discussion: http://postgr.es/m/CAEepm=2HzxAOKU6eCWTyvMwBy=fhGvbwDPM_fVps759tkyQSYQ@mail.gmail.com
* Provide DSM segment to ExecXXXInitializeWorker functions.Andres Freund2017-11-16
| | | | | | | | | | | | Previously, executor nodes running in parallel worker processes didn't have access to the dsm_segment object used for parallel execution. In order to support resource management based on DSM segment lifetime, they need that. So create a ParallelWorkerContext object to hold it and pass it to all InitializeWorker functions. Author: Thomas Munro Reviewed-By: Andres Freund Discussion: https://postgr.es/m/CAEepm=2W=cOkiZxcg6qiFQP-dHUe09aqTrEMM7yJDrHMhDv_RA@mail.gmail.com
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Avoid passing function pointers across process boundaries.Tom Lane2017-04-14
| | | | | | | | | | | | | | | | We'd already recognized that we can't pass function pointers across process boundaries for functions in loadable modules, since a shared library could get loaded at different addresses in different processes. But actually the practice doesn't work for functions in the core backend either, if we're using EXEC_BACKEND. This is the cause of recent failures on buildfarm member culicidae. Switch to passing a string function name in all cases. Something like this needs to be back-patched into 9.6, but let's see if the buildfarm likes it first. Petr Jelinek, with a bunch of basically-cosmetic adjustments by me Discussion: https://postgr.es/m/548f9c1d-eafa-e3fa-9da8-f0cc2f654e60@2ndquadrant.com
* Don't use bgw_main even to specify in-core bgworker entrypoints.Robert Haas2017-03-31
| | | | | | | | | | | | | | | On EXEC_BACKEND builds, this can fail if ASLR is in use. Backpatch to 9.5. On master, completely remove the bgw_main field completely, since there is no situation in which it is safe for an EXEC_BACKEND build. On 9.6 and 9.5, leave the field intact to avoid breaking things for third-party code that doesn't care about working under EXEC_BACKEND. Prior to 9.5, there are no in-core bgworker entrypoints. Petr Jelinek, reviewed by me. Discussion: http://postgr.es/m/09d8ad33-4287-a09b-a77f-77f8761adb5e@2ndquadrant.com
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Minor cleanup for access/transam/parallel.c.Tom Lane2016-08-01
| | | | | | | | | | | | | | | | | | | | ParallelMessagePending *must* be marked volatile, because it's set by a signal handler. On the other hand, it's pointless for HandleParallelMessageInterrupt to save/restore errno; that must be, and is, done at the outer level of the SIGUSR1 signal handler. Calling CHECK_FOR_INTERRUPTS() inside HandleParallelMessages, which itself is called from CHECK_FOR_INTERRUPTS(), seems both useless and hazardous. The comment claiming that this is needed to handle the error queue going away is certainly misguided, in any case. Improve a couple of error message texts, and use ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE to report loss of parallel worker connection, since that's what's used in e.g. tqueue.c. (Maybe it would be worth inventing a dedicated ERRCODE for this type of failure? But I do not think ERRCODE_INTERNAL_ERROR is appropriate.) Minor stylistic cleanups.
* Update copyright for 2016Bruce Momjian2016-01-02
| | | | Backpatch certain files through 9.1
* Update parallel executor support to reuse the same DSM.Robert Haas2015-10-30
| | | | | | | | | | | | | | | | Commit b0b0d84b3d663a148022e900ebfc164284a95f55 purported to make it possible to relaunch workers using the same parallel context, but it had an unpleasant race condition: we might reinitialize after the workers have sent their last control message but before they have dettached the DSM, leaving to crashes. Repair by introducing a new ParallelContext operation, ReinitializeParallelDSM. Adjust execParallel.c to use this new support, so that we can rescan a Gather node by relaunching workers but without needing to recreate the DSM. Amit Kapila, with some adjustments by me. Extracted from latest parallel sequential scan patch.
* Allow a parallel context to relaunch workers.Robert Haas2015-10-16
| | | | | | | | | This may allow some callers to avoid the overhead involved in tearing down a parallel context and then setting up a new one, which means releasing the DSM and then allocating and populating a new one. I suspect we'll want to revise the Gather node to make use of this new capability, but even if not it may be useful elsewhere and requires very little additional code.
* Fix a problem with parallel workers being unable to restore role.Robert Haas2015-10-16
| | | | | | | | | check_role() tries to verify that the user has permission to become the requested role, but this is inappropriate in a parallel worker, which needs to exactly recreate the master's authorization settings. So skip the check in that case. This fixes a bug in commit 924bcf4f16d54c55310b28f77686608684734f42.
* pgindent run for 9.5Bruce Momjian2015-05-23
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* Avoid using a C++ keyword as a structure member name.Robert Haas2015-05-05
| | | | Per request from Peter Eisentraut.
* Create an infrastructure for parallel computation in PostgreSQL.Robert Haas2015-04-30
This does four basic things. First, it provides convenience routines to coordinate the startup and shutdown of parallel workers. Second, it synchronizes various pieces of state (e.g. GUCs, combo CID mappings, transaction snapshot) from the parallel group leader to the worker processes. Third, it prohibits various operations that would result in unsafe changes to that state while parallelism is active. Finally, it propagates events that would result in an ErrorResponse, NoticeResponse, or NotifyResponse message being sent to the client from the parallel workers back to the master, from which they can then be sent on to the client. Robert Haas, Amit Kapila, Noah Misch, Rushabh Lathia, Jeevan Chalke. Suggestions and review from Andres Freund, Heikki Linnakangas, Noah Misch, Simon Riggs, Euler Taveira, and Jim Nasby.