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2020-01-08Reimplement nullification of walsender timestampAlvaro Herrera
Make the value null only at pg_stat_activity-output time, as suggested by Tom Lane, instead of messing with the internal state. This should appease buildfarm members with force_parallel_mode=regress, which are running parallel queries on logical replication walsenders. The fact that walsenders can run parallel queries should perhaps be studied more carefully, but for the moment let's get rid of the red blots in buildfarm. Backpatch to pg10, like the previous commit. Discussion: https://postgr.es/m/30804.1578438763@sss.pgh.pa.us
2020-01-07pg_stat_activity: show NULL stmt start time for walsendersAlvaro Herrera
Returning a non-NULL time is pointless, sinc a walsender is not a process that would be running normal transactions anyway, but the code was unintentionally exposing the process start time intermittently, which was not only bogus but it also confused monitoring systems looking for idle transactions. Fix by avoiding all updates in walsenders. Backpatch to 11, where walsenders started appearing in pg_stat_activity. Reported-by: Tomas Vondra Discussion: https://postgr.es/m/20191209234409.exe7osmyalwkt5j4@development
2019-12-18Remove shadow variables linked to RedoRecPtr in xlog.cMichael Paquier
This changes the routines in charge of recycling WAL segments past the last redo LSN to not use anymore "RedoRecPtr" as a local variable, which is also available in the context of the session as a static declaration, replacing it with "lastredoptr". This confusion has been introduced by d9fadbf, so backpatch down to v11 like the other commit. Thanks to Tom Lane, Robert Haas, Alvaro Herrera, Mark Dilger and Kyotaro Horiguchi for the input provided. Author: Ranier Vilela Discussion: https://postgr.es/m/MN2PR18MB2927F7B5F690065E1194B258E35D0@MN2PR18MB2927.namprd18.prod.outlook.com Backpatch-through: 11
2019-12-17Change overly strict Assert in TransactionGroupUpdateXidStatus.Amit Kapila
This Assert thought that an overflowed transaction can never get registered for the group update.  But that is not true, because even when the number of children for a transaction got reduced, the overflow flag is not changed. And, for group update, we only care about the current number of children for a transaction that is being committed. Based on comments by Andres Freund, remove a redundant Assert in TransactionIdSetPageStatus as we already had a static Assert for the same condition a few lines earlier. Reported-by: Vignesh C Author: Dilip Kumar Reviewed-by: Amit Kapila Backpatch-through: 11 Discussion: https://postgr.es/m/CAFiTN-s5=uJw-Z6JC9gcqtBSjXsrHnU63PXBrA=pnBjqnkm5UA@mail.gmail.com
2019-11-24Avoid assertion failure with LISTEN in a serializable transaction.Tom Lane
If LISTEN is the only action in a serializable-mode transaction, and the session was not previously listening, and the notify queue is not empty, predicate.c reported an assertion failure. That happened because we'd acquire the transaction's initial snapshot during PreCommit_Notify, which was called *after* predicate.c expects any such snapshot to have been established. To fix, just swap the order of the PreCommit_Notify and PreCommit_CheckForSerializationFailure calls during CommitTransaction. This will imply holding the notify-insertion lock slightly longer, but the difference could only be meaningful in serializable mode, which is an expensive option anyway. It appears that this is just an assertion failure, with no consequences in non-assert builds. A snapshot used only to scan the notify queue could not have been involved in any serialization conflicts, so there would be nothing for PreCommit_CheckForSerializationFailure to do except assign it a prepareSeqNo and set the SXACT_FLAG_PREPARED flag. And given no conflicts, neither of those omissions affect the behavior of ReleasePredicateLocks. This admittedly once-over-lightly analysis is backed up by the lack of field reports of trouble. Per report from Mark Dilger. The bug is old, so back-patch to all supported branches; but the new test case only goes back to 9.6, for lack of adequate isolationtester infrastructure before that. Discussion: https://postgr.es/m/3ac7f397-4d5f-be8e-f354-440020675694@gmail.com Discussion: https://postgr.es/m/13881.1574557302@sss.pgh.pa.us
2019-11-07Fix assertion failure when running pgbench -s.Fujii Masao
If there is the WAL page that the continuation WAL record just fits within (i.e., the continuation record ends just at the end of the page) and the LSN in such page is specified with -s option, previously pg_waldump caused an assertion failure. The cause of this assertion failure was that XLogFindNextRecord() that pg_waldump -s calls mistakenly handled such special WAL page. This commit changes XLogFindNextRecord() so that it can handle such WAL page correctly. Back-patch to all supported versions. Author: Andrey Lepikhov Reviewed-by: Fujii Masao, Michael Paquier Discussion: https://postgr.es/m/99303554-5dd5-06e6-f943-b3005ccd6edd@postgrespro.ru
2019-10-27Fix initialization of fake LSN for unlogged relationsMichael Paquier
9155580 has changed the value of the first fake LSN for unlogged relations from 1 to FirstNormalUnloggedLSN (aka 1000), GiST requiring a non-zero LSN on some pages to allow an interlocking logic to work, but its value was still initialized to 1 at the beginning of recovery or after running pg_resetwal. This fixes the initialization for both code paths. Author: Takayuki Tsunakawa Reviewed-by: Dilip Kumar, Kyotaro Horiguchi, Michael Paquier Discussion: https://postgr.es/m/OSBPR01MB2503CE851940C17DE44AE3D9FE6F0@OSBPR01MB2503.jpnprd01.prod.outlook.com Backpatch-through: 12
2019-10-18Fix failure of archive recovery with recovery_min_apply_delay enabled.Fujii Masao
recovery_min_apply_delay parameter is intended for use with streaming replication deployments. However, the document clearly explains that the parameter will be honored in all cases if it's specified. So it should take effect even if in archive recovery. But, previously, archive recovery with recovery_min_apply_delay enabled always failed, and caused assertion failure if --enable-caasert is enabled. The cause of this problem is that; the ownership of recoveryWakeupLatch that recovery_min_apply_delay uses was taken only when standby mode is requested. So unowned latch could be used in archive recovery, and which caused the failure. This commit changes recovery code so that the ownership of recoveryWakeupLatch is taken even in archive recovery. Which prevents archive recovery with recovery_min_apply_delay from failing. Back-patch to v9.4 where recovery_min_apply_delay was added. Author: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CAHGQGwEyD6HdZLfdWc+95g=VQFPR4zQL4n+yHxQgGEGjaSVheQ@mail.gmail.com
2019-10-18Make crash recovery ignore recovery_min_apply_delay setting.Fujii Masao
In v11 or before, this setting could not take effect in crash recovery because it's specified in recovery.conf and crash recovery always starts without recovery.conf. But commit 2dedf4d9a8 integrated recovery.conf into postgresql.conf and which unexpectedly allowed this setting to take effect even in crash recovery. This is definitely not good behavior. To fix the issue, this commit makes crash recovery always ignore recovery_min_apply_delay setting. Back-patch to v12 where the issue was added. Author: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CAHGQGwEyD6HdZLfdWc+95g=VQFPR4zQL4n+yHxQgGEGjaSVheQ@mail.gmail.com Discussion: https://postgr.es/m/e445616d-023e-a268-8aa1-67b8b335340c@pgmasters.net
2019-10-11Make crash recovery ignore restore_command and recovery_end_command settings.Fujii Masao
In v11 or before, those settings could not take effect in crash recovery because they are specified in recovery.conf and crash recovery always starts without recovery.conf. But commit 2dedf4d9a8 integrated recovery.conf into postgresql.conf and which unexpectedly allowed those settings to take effect even in crash recovery. This is definitely not good behavior. To fix the issue, this commit makes crash recovery always ignore restore_command and recovery_end_command settings. Back-patch to v12 where the issue was added. Author: Fujii Masao Reviewed-by: Peter Eisentraut Discussion: https://postgr.es/m/e445616d-023e-a268-8aa1-67b8b335340c@pgmasters.net
2019-10-02Remove temporary WAL and history files at the end of archive recoveryMichael Paquier
cbc55da has reworked the order of some actions at the end of archive recovery. Unfortunately this overlooked the fact that the startup process needs to remove RECOVERYXLOG (for temporary WAL segment newly recovered from archives) and RECOVERYHISTORY (for temporary history file) at this step, leaving the files around even after recovery ended. Backpatch to 9.5, like the previous commit. Author: Sawada Masahiko Reviewed-by: Fujii Masao, Michael Paquier Discussion: https://postgr.es/m/CAD21AoBO_eDQub6zojFnWtnmutRBWvYf7=cW4Hsqj+U_R26w3Q@mail.gmail.com Backpatch-through: 9.5
2019-09-30Make crash recovery ignore recovery target settings.Fujii Masao
In v11 or before, recovery target settings could not take effect in crash recovery because they are specified in recovery.conf and crash recovery always starts without recovery.conf. But commit 2dedf4d9a8 integrated recovery.conf into postgresql.conf and which unexpectedly allowed recovery target settings to take effect even in crash recovery. This is definitely not good behavior. To fix the issue, this commit makes crash recovery always ignore recovery target settings. Back-patch to v12. Author: Peter Eisentraut Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/e445616d-023e-a268-8aa1-67b8b335340c@pgmasters.net
2019-09-23Message style fixesPeter Eisentraut
2019-09-08Fix behavior of AND CHAIN outside of explicit transaction blocksPeter Eisentraut
When using COMMIT AND CHAIN or ROLLBACK AND CHAIN not in an explicit transaction block, the previous implementation would leave a transaction block active in the ROLLBACK case but not the COMMIT case. To fix for now, error out when using these commands not in an explicit transaction block. This restriction could be lifted if a sensible definition and implementation is found. Bug: #15977 Author: fn ln <emuser20140816@gmail.com> Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>
2019-09-06Make pg_promote() detect postmaster death while waiting for promotion to end.Fujii Masao
Previously even if postmaster died and WaitLatch() woke up with that event while pg_promote() was waiting for the standby promotion to finish, pg_promote() did nothing special and kept waiting until timeout occurred. This could cause a busy loop. This patch make pg_promote() return false immediately when postmaster dies, to avoid such a busy loop. Back-patch to v12 where pg_promote() was added. Author: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CAHGQGwEs9ROgSp+QF+YdDU+xP8W=CY1k-_Ov-d_Z3JY+to3eXA@mail.gmail.com
2019-09-03Better error messages for short reads/writes in SLRUPeter Eisentraut
This avoids getting a Could not read from file ...: Success. for a short read or write (since errno is not set in that case). Instead, report a more specific error messages. Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://www.postgresql.org/message-id/flat/5de61b6b-8be9-7771-0048-860328efe027%402ndquadrant.com
2019-06-30Don't call data type input functions in GUC check hooksPeter Eisentraut
Instead of calling pg_lsn_in() in check_recovery_target_lsn and timestamptz_in() in check_recovery_target_time, reorganize the respective code so that we don't raise any errors in the check hooks. The previous code tried to use PG_TRY/PG_CATCH to handle errors in a way that is not safe, so now the code contains no ereport() calls and can operate safely within the GUC error handling system. Moreover, since the interpretation of the recovery_target_time string may depend on the time zone, we cannot do the final processing of that string until all the GUC processing is done. Instead, check_recovery_target_time() now does some parsing for syntax checking, but the actual conversion to a timestamptz value is done later in the recovery code that uses it. Reported-by: Andres Freund <andres@anarazel.de> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://www.postgresql.org/message-id/flat/20190611061115.njjwkagvxp4qujhp%40alap3.anarazel.de
2019-06-17Fix more typos and inconsistencies in the treeMichael Paquier
Author: Alexander Lakhin Discussion: https://postgr.es/m/0a5419ea-1452-a4e6-72ff-545b1a5a8076@gmail.com
2019-06-08Update stale comments, and fix comment typos.Noah Misch
2019-06-08Fix assorted inconsistencies.Amit Kapila
There were a number of issues in the recent commits which include typos, code and comments mismatch, leftover function declarations. Fix them. Reported-by: Alexander Lakhin Author: Alexander Lakhin, Amit Kapila and Amit Langote Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/ef0c0232-0c1d-3a35-63d4-0ebd06e31387@gmail.com
2019-05-22Phase 2 pgindent run for v12.Tom Lane
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
2019-05-22Initial pgindent run for v12.Tom Lane
This is still using the 2.0 version of pg_bsd_indent. I thought it would be good to commit this separately, so as to document the differences between 2.0 and 2.1 behavior. Discussion: https://postgr.es/m/16296.1558103386@sss.pgh.pa.us
2019-05-21Fix comment for issue_xlog_fsync().Fujii Masao
"segno" is the argument for the function, not "log" and "seg". Author: Antonin Houska Discussion: https://postgr.es/m/11863.1558361020@spoje.net
2019-05-08Clean up the behavior and API of catalog.c's is-catalog-relation tests.Tom Lane
The right way for IsCatalogRelation/Class to behave is to return true for OIDs less than FirstBootstrapObjectId (not FirstNormalObjectId), without any of the ad-hoc fooling around with schema membership. The previous code was wrong because (1) it claimed that information_schema tables were not catalog relations but their toast tables were, which is silly; and (2) if you dropped and recreated information_schema, which is a supported operation, the behavior changed. That's even sillier. With this definition, "catalog relations" are exactly the ones traceable to the postgres.bki data, which seems like what we want. With this simplification, we don't actually need access to the pg_class tuple to identify a catalog relation; we only need its OID. Hence, replace IsCatalogClass with "IsCatalogRelationOid(oid)". But keep IsCatalogRelation as a convenience function. This allows fixing some arguably-wrong semantics in contrib/sepgsql and ReindexRelationConcurrently, which were using an IsSystemNamespace test where what they really should be using is IsCatalogRelationOid. The previous coding failed to protect toast tables of system catalogs, and also was not on board with the general principle that user-created tables do not become catalogs just by virtue of being renamed into pg_catalog. We can also get rid of a messy hack in ReindexMultipleTables. While we're at it, also rename IsSystemNamespace to IsCatalogNamespace, because the previous name invited confusion with the more expansive semantics used by IsSystemRelation/Class. Also improve the comments in catalog.c. There are a few remaining places in replication-related code that are special-casing OIDs below FirstNormalObjectId. I'm inclined to think those are wrong too, and if there should be any special case it should just extend to FirstBootstrapObjectId. But first we need to debate whether a FOR ALL TABLES publication should include information_schema. Discussion: https://postgr.es/m/21697.1557092753@sss.pgh.pa.us Discussion: https://postgr.es/m/15150.1557257111@sss.pgh.pa.us
2019-05-08Remove leftover reference to old "flat file" mechanism in a comment.Heikki Linnakangas
The flat file mechanism was removed in PostgreSQL 9.0.
2019-05-07Revert "Avoid the creation of the free space map for small heap relations".Amit Kapila
This feature was using a process local map to track the first few blocks in the relation. The map was reset each time we get the block with enough freespace. It was discussed that it would be better to track this map on a per-relation basis in relcache and then invalidate the same whenever vacuum frees up some space in the page or when FSM is created. The new design would be better both in terms of API design and performance. List of commits reverted, in reverse chronological order: 06c8a5090e Improve code comments in b0eaa4c51b. 13e8643bfc During pg_upgrade, conditionally skip transfer of FSMs. 6f918159a9 Add more tests for FSM. 9c32e4c350 Clear the local map when not used. 29d108cdec Update the documentation for FSM behavior.. 08ecdfe7e5 Make FSM test portable. b0eaa4c51b Avoid creation of the free space map for small heap relations. Discussion: https://postgr.es/m/20190416180452.3pm6uegx54iitbt5@alap3.anarazel.de
2019-04-30Message style fixesAlvaro Herrera
2019-04-17Simplify some ERROR paths clearing wait events and transient filesMichael Paquier
Transient files and wait events get normally cleaned up when seeing an exception (be it in the context of a transaction for a backend or another process like the checkpointer), hence there is little point in complicating error code paths to do this work. This shaves a bit of code, and removes some extra handling with errno which needed to be preserved during the cleanup steps done. Reported-by: Masahiko Sawada Author: Michael Paquier Reviewed-by: Tom Lane, Masahiko Sawada Discussion: https://postgr.es/m/CAD21AoDhHYVq5KkXfkaHhmjA-zJYj-e4teiRAJefvXuKJz1tKQ@mail.gmail.com
2019-04-12Fix GetNewTransactionId()'s interaction with xidVacLimit.Thomas Munro
Commit ad308058 switched to returning a FullTransactionId, but failed to load the potentially updated value in the case where xidVacLimit is reached and we release and reacquire the lock. Repair, closing bug #15727. While reviewing that commit, also fix the size computation used by EstimateTransactionStateSize() and switch to the mul_size() macro traditionally used in such expressions. Author: Thomas Munro Reported-by: Roman Zharkov Discussion: https://postgr.es/m/15727-0be246e7d852d229%40postgresql.org
2019-04-10Avoid counting transaction stats for parallel worker cooperatingAmit Kapila
transaction. The transaction that is initiated by the parallel worker to cooperate with the actual transaction started by the main backend to complete the query execution should not be counted as a separate transaction. The other internal transactions started and committed by the parallel worker are still counted as separate transactions as we that is what we do in other places like autovacuum. This will partially fix the bloat in transaction stats due to additional transactions performed by parallel workers. For a complete fix, we need to decide how we want to show all the transactions that are started internally for various operations and that is a matter of separate patch. Reported-by: Haribabu Kommi Author: Haribabu Kommi Reviewed-by: Amit Kapila, Jamison Kirk and Rahila Syed Backpatch-through: 9.6 Discussion: https://postgr.es/m/CAJrrPGc9=jKXuScvNyQ+VNhO0FZk7LLAShAJRyZjnedd2D61EQ@mail.gmail.com
2019-04-04Refactor the fsync queue for wider use.Thomas Munro
Previously, md.c and checkpointer.c were tightly integrated so that fsync calls could be handed off and processed in the background. Introduce a system of callbacks and file tags, so that other modules can hand off fsync work in the same way. For now only md.c uses the new interface, but other users are being proposed. Since there may be use cases that are not strictly SMGR implementations, use a new function table for sync handlers rather than extending the traditional SMGR one. Instead of using a bitmapset of segment numbers for each RelFileNode in the checkpointer's hash table, make the segment number part of the key. This requires sending explicit "forget" requests for every segment individually when relations are dropped, but suits the file layout schemes of proposed future users better (ie sparse or high segment numbers). Author: Shawn Debnath and Thomas Munro Reviewed-by: Thomas Munro, Andres Freund Discussion: https://postgr.es/m/CAEepm=2gTANm=e3ARnJT=n0h8hf88wqmaZxk0JYkxw+b21fNrw@mail.gmail.com
2019-04-03Log all statements from a sample of transactionsAlvaro Herrera
This is useful to obtain a view of the different transaction types in an application, regardless of the durations of the statements each runs. Author: Adrien Nayrat Reviewed-by: Masahiko Sawada, Hayato Kuroda, Andres Freund
2019-04-03Generate less WAL during GiST, GIN and SP-GiST index build.Heikki Linnakangas
Instead of WAL-logging every modification during the build separately, first build the index without any WAL-logging, and make a separate pass through the index at the end, to write all pages to the WAL. This significantly reduces the amount of WAL generated, and is usually also faster, despite the extra I/O needed for the extra scan through the index. WAL generated this way is also faster to replay. For GiST, the LSN-NSN interlock makes this a little tricky. All pages must be marked with a valid (i.e. non-zero) LSN, so that the parent-child LSN-NSN interlock works correctly. We now use magic value 1 for that during index build. Change the fake LSN counter to begin from 1000, so that 1 is safely smaller than any real or fake LSN. 2 would've been enough for our purposes, but let's reserve a bigger range, in case we need more special values in the future. Author: Anastasia Lubennikova, Andrey V. Lepikhov Reviewed-by: Heikki Linnakangas, Dmitry Dolgov
2019-04-02Add support for partial TOAST decompressionStephen Frost
When asked for a slice of a TOAST entry, decompress enough to return the slice instead of decompressing the entire object. For use cases where the slice is at, or near, the beginning of the entry, this avoids a lot of unnecessary decompression work. This changes the signature of pglz_decompress() by adding a boolean to indicate if it's ok for the call to finish before consuming all of the source or destination buffers. Author: Paul Ramsey Reviewed-By: Rafia Sabih, Darafei Praliaskouski, Regina Obe Discussion: https://postgr.es/m/CACowWR07EDm7Y4m2kbhN_jnys%3DBBf9A6768RyQdKm_%3DNpkcaWg%40mail.gmail.com
2019-04-02Add wal_recycle and wal_init_zero GUCs.Thomas Munro
On at least ZFS, it can be beneficial to create new WAL files every time and not to bother zero-filling them. Since it's not clear which other filesystems might benefit from one or both of those things, add individual GUCs to control those two behaviors independently and make only very general statements in the docs. Author: Jerry Jelinek, with some adjustments by Thomas Munro Reviewed-by: Alvaro Herrera, Andres Freund, Tomas Vondra, Robert Haas and others Discussion: https://postgr.es/m/CACPQ5Fo00QR7LNAcd1ZjgoBi4y97%2BK760YABs0vQHH5dLdkkMA%40mail.gmail.com
2019-04-01Unified logging system for command-line programsPeter Eisentraut
This unifies the various ad hoc logging (message printing, error printing) systems used throughout the command-line programs. Features: - Program name is automatically prefixed. - Message string does not end with newline. This removes a common source of inconsistencies and omissions. - Additionally, a final newline is automatically stripped, simplifying use of PQerrorMessage() etc., another common source of mistakes. - I converted error message strings to use %m where possible. - As a result of the above several points, more translatable message strings can be shared between different components and between frontends and backend, without gratuitous punctuation or whitespace differences. - There is support for setting a "log level". This is not meant to be user-facing, but can be used internally to implement debug or verbose modes. - Lazy argument evaluation, so no significant overhead if logging at some level is disabled. - Some color in the messages, similar to gcc and clang. Set PG_COLOR=auto to try it out. Some colors are predefined, but can be customized by setting PG_COLORS. - Common files (common/, fe_utils/, etc.) can handle logging much more simply by just using one API without worrying too much about the context of the calling program, requiring callbacks, or having to pass "progname" around everywhere. - Some programs called setvbuf() to make sure that stderr is unbuffered, even on Windows. But not all programs did that. This is now done centrally. Soft goals: - Reduces vertical space use and visual complexity of error reporting in the source code. - Encourages more deliberate classification of messages. For example, in some cases it wasn't clear without analyzing the surrounding code whether a message was meant as an error or just an info. - Concepts and terms are vaguely aligned with popular logging frameworks such as log4j and Python logging. This is all just about printing stuff out. Nothing affects program flow (e.g., fatal exits). The uses are just too varied to do that. Some existing code had wrappers that do some kind of print-and-exit, and I adapted those. I tried to keep the output mostly the same, but there is a lot of historical baggage to unwind and special cases to consider, and I might not always have succeeded. One significant change is that pg_rewind used to write all error messages to stdout. That is now changed to stderr. Reviewed-by: Donald Dong <xdong@csumb.edu> Reviewed-by: Arthur Zakirov <a.zakirov@postgrespro.ru> Discussion: https://www.postgresql.org/message-id/flat/6a609b43-4f57-7348-6480-bd022f924310@2ndquadrant.com
2019-03-29Warn more strongly about the dangers of exclusive backup mode.Robert Haas
Especially, warn about the hazards of mishandling the backup_label file. Adjust a couple of server messages to be more clear about the hazards associated with removing backup_label files, too. David Steele and Robert Haas, reviewed by Laurenz Albe, Martín Marqués, Peter Eisentraut, and Magnus Hagander. Discussion: http://postgr.es/m/7d85c387-000e-16f0-e00b-50bf83c22127@pgmasters.net
2019-03-29Fix typo.Thomas Munro
Author: Masahiko Sawada
2019-03-28Use FullTransactionId for the transaction stack.Thomas Munro
Provide GetTopFullTransactionId() and GetCurrentFullTransactionId(). The intended users of these interfaces are access methods that use xids for visibility checks but don't want to have to go back and "freeze" existing references some time later before the 32 bit xid counter wraps around. Use a new struct to serialize the transaction state for parallel query, because FullTransactionId doesn't fit into the previous serialization scheme very well. Author: Thomas Munro Reviewed-by: Heikki Linnakangas Discussion: https://postgr.es/m/CAA4eK1%2BMv%2Bmb0HFfWM9Srtc6MVe160WFurXV68iAFMcagRZ0dQ%40mail.gmail.com
2019-03-28Add basic infrastructure for 64 bit transaction IDs.Thomas Munro
Instead of inferring epoch progress from xids and checkpoints, introduce a 64 bit FullTransactionId type and use it to track xid generation. This fixes an unlikely bug where the epoch is reported incorrectly if the range of active xids wraps around more than once between checkpoints. The only user-visible effect of this commit is to correct the epoch used by txid_current() and txid_status(), also visible with pg_controldata, in those rare circumstances. It also creates some basic infrastructure so that later patches can use 64 bit transaction IDs in more places. The new type is a struct that we pass by value, as a form of strong typedef. This prevents the sort of accidental confusion between TransactionId and FullTransactionId that would be possible if we were to use a plain old uint64. Author: Thomas Munro Reported-by: Amit Kapila Reviewed-by: Andres Freund, Tom Lane, Heikki Linnakangas Discussion: https://postgr.es/m/CAA4eK1%2BMv%2Bmb0HFfWM9Srtc6MVe160WFurXV68iAFMcagRZ0dQ%40mail.gmail.com
2019-03-24Transaction chainingPeter Eisentraut
Add command variants COMMIT AND CHAIN and ROLLBACK AND CHAIN, which start new transactions with the same transaction characteristics as the just finished one, per SQL standard. Support for transaction chaining in PL/pgSQL is also added. This functionality is especially useful when running COMMIT in a loop in PL/pgSQL. Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr> Discussion: https://www.postgresql.org/message-id/flat/28536681-324b-10dc-ade8-ab46f7645a5a@2ndquadrant.com
2019-03-18Refactor more code logic to update the control fileMichael Paquier
ce6afc6 has begun the refactoring work by plugging pg_rewind into a central routine to update the control file, and left around two extra copies, with one in xlog.c for the backend and one in pg_resetwal.c. By adding an extra option to the central routine in controldata_utils.c to control if a flush of the control file needs to be done, it is proving to be straight-forward to make xlog.c and pg_resetwal.c use the central code path at the condition of moving the wait event tracking there. Hence, this allows to have only one central code path to update the control file, shaving the code from the duplicates. This refactoring actually fixes a problem in pg_resetwal. Previously, the control file was first removed before being recreated. So if a crash happened between the moment the file was removed and the moment the file was created, then it would have been possible to not have a control file anymore in the database folder. Author: Fabien Coelho Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/alpine.DEB.2.21.1903170935210.2506@lancre
2019-03-16Avoid casting away a constPeter Eisentraut
2019-03-15Enable parallel query with SERIALIZABLE isolation.Thomas Munro
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
2019-03-11Adjust error message for partial writes in WAL segmentsMichael Paquier
93473c6 has removed openLogOff, changing on the way the error message which is used to report partial writes to WAL segments. The newly-introduced error message used the offset up to which the write has happened, keeping always the same total length to write. This changes the error message so as the number of bytes left to write are reported. Reported-by: Michael Paquier Author: Robert Haas Discussion: https://postgr.es/m/20190306235251.GA17293@paquier.xyz
2019-03-09Tighten use of OpenTransientFile and CloseTransientFileMichael Paquier
This fixes two sets of issues related to the use of transient files in the backend: 1) OpenTransientFile() has been used in some code paths with read-write flags while read-only is sufficient, so switch those calls to be read-only where necessary. These have been reported by Joe Conway. 2) When opening transient files, it is up to the caller to close the file descriptors opened. In error code paths, CloseTransientFile() gets called to clean up things before issuing an error. However in normal exit paths, a lot of callers of CloseTransientFile() never actually reported errors, which could leave a file descriptor open without knowing about it. This is an issue I complained about a couple of times, but never had the courage to write and submit a patch, so here we go. Note that one frontend code path is impacted by this commit so as an error is issued when fetching control file data, making backend and frontend to be treated consistently. Reported-by: Joe Conway, Michael Paquier Author: Michael Paquier Reviewed-by: Álvaro Herrera, Georgios Kokolatos, Joe Conway Discussion: https://postgr.es/m/20190301023338.GD1348@paquier.xyz Discussion: https://postgr.es/m/c49b69ec-e2f7-ff33-4f17-0eaa4f2cef27@joeconway.com
2019-03-06Removed unused variable, openLogOff.Robert Haas
Antonin Houska Discussion: http://postgr.es/m/30413.1551870730@localhost
2019-02-25Make release of 2PC identifier and locks consistent in COMMIT PREPAREDMichael Paquier
When preparing a transaction in two-phase commit, a dummy PGPROC entry holding the GID used for the transaction is registered, which gets released once COMMIT PREPARED is run. Prior releasing its shared memory state, all the locks taken in the prepared transaction are released using a dedicated set of callbacks (pgstat and multixact having similar callbacks), which may cause the locks to be released before the GID is set free. Hence, there is a small window where lock conflicts could happen, for example: - Transaction A releases its locks, still holding its GID in shared memory. - Transaction B held a lock which conflicted with locks of transaction A. - Transaction B continues its processing, reusing the same GID as transaction A. - Transaction B fails because of a conflicting GID, already in use by transaction A. This commit changes the shared memory state release so as post-commit callbacks and predicate lock cleanup happen consistently with the shared memory state cleanup for the dummy PGPROC entry. The race window is small and 2PC had this issue from the start, so no backpatch is done. On top if that fixes discussed involved ABI breakages, which are not welcome in stable branches. Reported-by: Oleksii Kliukin, Ildar Musin Diagnosed-by: Oleksii Kliukin, Ildar Musin Author: Michael Paquier Reviewed-by: Masahiko Sawada, Oleksii Kliukin Discussion: https://postgr.es/m/BF9B38A4-2BFF-46E8-BA87-A2D00A8047A6@hintbits.com
2019-02-23Fix incorrect function reference in comment of twophase.cMichael Paquier
The header block of TwoPhaseGetDummyBackendId mentioned incorrectly TwoPhaseGetDummyProc. Reported-by: Oleksii Kliukin Discussion: https://postgr.es/m/D8336E40-BBE1-4954-98BB-7830D3F5CB36@hintbits.com
2019-02-18Avoid some unnecessary block reads in WAL readerMichael Paquier
When reading a new page internally and depending on the way the WAL reader facility gets used by plugins, the current implementation of the WAL reader may finish by reading a block multiple times while it is not actually necessary as the requested data length may be equal to what has been already read. This can happen for any size, but is more likely to happen at the end of a page. This can cause performance penalties in plugins which rely on the block reads to be purely sequential, zlib not liking backward reads for example. The new behavior also shaves some cycles when doing recovery. Author: Arthur Zakirov Reviewed-by: Andrey Lepikhov, Michael Paquier, Grigory Smolkin Discussion: https://postgr.es/m/2ddf4a32-517e-d6f4-d992-4a63b6035bfd@postgrespro.ru