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* Formatting improvements in config file samplesPeter Eisentraut2017-06-09
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* Update code commentsPeter Eisentraut2017-06-09
| | | | Author: Neha Khatri <nehakhatri5@gmail.com>
* Clean up latch related code.Andres Freund2017-06-06
| | | | | | | | | | | | | | | | | | | | | | The larger part of this patch replaces usages of MyProc->procLatch with MyLatch. The latter works even early during backend startup, where MyProc->procLatch doesn't yet. While the affected code shouldn't run in cases where it's not initialized, it might get copied into places where it might. Using MyLatch is simpler and a bit faster to boot, so there's little point to stick with the previous coding. While doing so I noticed some weaknesses around newly introduced uses of latches that could lead to missed events, and an omitted CHECK_FOR_INTERRUPTS() call in worker_spi. As all the actual bugs are in v10 code, there doesn't seem to be sufficient reason to backpatch this. Author: Andres Freund Discussion: https://postgr.es/m/20170606195321.sjmenrfgl2nu6j63@alap3.anarazel.de https://postgr.es/m/20170606210405.sim3yl6vpudhmufo@alap3.anarazel.de Backpatch: -
* Prevent possibility of panics during shutdown checkpoint.Andres Freund2017-06-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the checkpointer writes the shutdown checkpoint, it checks afterwards whether any WAL has been written since it started and throws a PANIC if so. At that point, only walsenders are still active, so one might think this could not happen, but walsenders can also generate WAL, for instance in BASE_BACKUP and logical decoding related commands (e.g. via hint bits). So they can trigger this panic if such a command is run while the shutdown checkpoint is being written. To fix this, divide the walsender shutdown into two phases. First, checkpointer, itself triggered by postmaster, sends a PROCSIG_WALSND_INIT_STOPPING signal to all walsenders. If the backend is idle or runs an SQL query this causes the backend to shutdown, if logical replication is in progress all existing WAL records are processed followed by a shutdown. Otherwise this causes the walsender to switch to the "stopping" state. In this state, the walsender will reject any further replication commands. The checkpointer begins the shutdown checkpoint once all walsenders are confirmed as stopping. When the shutdown checkpoint finishes, the postmaster sends us SIGUSR2. This instructs walsender to send any outstanding WAL, including the shutdown checkpoint record, wait for it to be replicated to the standby, and then exit. Author: Andres Freund, based on an earlier patch by Michael Paquier Reported-By: Fujii Masao, Andres Freund Reviewed-By: Michael Paquier Discussion: https://postgr.es/m/20170602002912.tqlwn4gymzlxpvs2@alap3.anarazel.de Backpatch: 9.4, where logical decoding was introduced
* Revert "Prevent panic during shutdown checkpoint"Andres Freund2017-06-05
| | | | | | | | | | | This reverts commit 086221cf6b1727c2baed4703c582f657b7c5350e, which was made to master only. The approach implemented in the above commit has some issues. While those could easily be fixed incrementally, doing so would make backpatching considerably harder, so instead first revert this patch. Discussion: https://postgr.es/m/20170602002912.tqlwn4gymzlxpvs2@alap3.anarazel.de
* Don't be so trusting that shm_toc_lookup() will always succeed.Tom Lane2017-06-05
| | | | | | | | | | | | | | | | | | Given the possibility of race conditions and so on, it seems entirely unsafe to just assume that shm_toc_lookup() always finds the key it's looking for --- but that was exactly what all but one call site were doing. To fix, add a "bool noError" argument, similarly to what we have in many other functions, and throw an error on an unexpected lookup failure. Remove now-redundant Asserts that a rather random subset of call sites had. I doubt this will throw any light on buildfarm member lorikeet's recent failures, because if an unnoticed lookup failure were involved, you'd kind of expect a null-pointer-dereference crash rather than the observed symptom. But you never know ... and this is better coding practice even if it never catches anything. Discussion: https://postgr.es/m/9697.1496675981@sss.pgh.pa.us
* Assorted translatable string fixesAlvaro Herrera2017-06-04
| | | | | Mark our rusage reportage string translatable; remove quotes from type names; unify formatting of very similar messages.
* Restore accidentally-removed line.Robert Haas2017-05-31
| | | | | | | | Commit 88e66d193fbaf756b3cc9bf94cad116aacbb355b is to blame. Masahiko Sawada Discussion: http://postgr.es/m/CAD21AoAXeb7O4hgg+efs8JT_SxpR4doAH5c5s-Z5WoRLstBZJA@mail.gmail.com
* brin: Don't crash on auto-summarizationAlvaro Herrera2017-05-30
| | | | | | | | | | | | | | We were trying to free a pointer into a shared buffer, which never works; and we were failing to release the buffer lock appropriately. Fix those omissions. While at it, improve documentation for brinGetTupleForHeapBlock, the inadequacy of which evidently caused these bugs in the first place. Reported independently by Zhou Digoal (bug #14668) and Alexander Sosna. Discussion: https://postgr.es/m/8c31c11b-6adb-228d-22c2-4ace89fc9209@credativ.de Discussion: https://postgr.es/m/20170524063323.29941.46339@wrigleys.postgresql.org
* Fix wording in amvalidate error messagesAlvaro Herrera2017-05-30
| | | | | | | | Remove some gratuituous message differences by making the AM name previously embedded in each message be a %s instead. While at it, get rid of terminology that's unclear and unnecessary in one message. Discussion: https://postgr.es/m/20170523001557.bq2hbq7hxyvyw62q@alvherre.pgsql
* Fix typo in commentMagnus Hagander2017-05-22
| | | | Author: Masahiko Sawada
* Post-PG 10 beta1 pgindent runBruce Momjian2017-05-17
| | | | perltidy run not included.
* Standardize "WAL location" terminologyPeter Eisentraut2017-05-12
| | | | Other previously used terms were "WAL position" or "log position".
* Replace "transaction log" with "write-ahead log"Peter Eisentraut2017-05-12
| | | | | This makes documentation and error messages match the renaming of "xlog" to "wal" in APIs and file naming.
* Rename WAL-related functions and views to use "lsn" not "location".Tom Lane2017-05-11
| | | | | | | | | | | | | | | Per discussion, "location" is a rather vague term that could refer to multiple concepts. "LSN" is an unambiguous term for WAL locations and should be preferred. Some function names, view column names, and function output argument names used "lsn" already, but others used "location", as well as yet other terms such as "wal_position". Since we've already renamed a lot of things in this area from "xlog" to "wal" for v10, we may as well incur a bit more compatibility pain and make these names all consistent. David Rowley, minor additional docs hacking by me Discussion: https://postgr.es/m/CAKJS1f8O0njDKe8ePFQ-LK5-EjwThsDws6ohJ-+c6nWK+oUxtg@mail.gmail.com
* Revert "Permit dump/reload of not-too-large >1GB tuples"Alvaro Herrera2017-05-10
| | | | | | | | | | | | | | | | | | | This reverts commits fa2fa9955280 and 42f50cb8fa98. While the functionality that was intended to be provided by these commits is desired, the patch didn't actually solve as many of the problematic situations as we hoped, and it created a bunch of its own problems. Since we're going to require more extensive changes soon for other reasons and users have been working around these problems for a long time already, there is no point in spending effort in fixing this halfway measure. Per complaint from Tom Lane. Discussion: https://postgr.es/m/21407.1484606922@sss.pgh.pa.us (Commit fa2fa9955280 had already been reverted in branches 9.5 as f858524ee4f and 9.6 as e9e44a0953, so this touches master only. Commit 42f50cb8fa98 was not present in the older branches.)
* Remove no-longer-needed compatibility code for hash indexes.Robert Haas2017-05-09
| | | | | | | | | | Because commit ea69a0dead5128c421140dc53fac165ba4af8520 bumped the HASH_VERSION, we don't need to worry about PostgreSQL 10 seeing bucket pages from earlier versions. Amit Kapila Discussion: http://postgr.es/m/CAA4eK1LAo4DGwh+mi-G3U8Pj1WkBBeFL38xdCnUHJv1z4bZFkQ@mail.gmail.com
* Prevent panic during shutdown checkpointPeter Eisentraut2017-05-05
| | | | | | | | | | | | | | | | | | | | | | | | | When the checkpointer writes the shutdown checkpoint, it checks afterwards whether any WAL has been written since it started and throws a PANIC if so. At that point, only walsenders are still active, so one might think this could not happen, but walsenders can also generate WAL, for instance in BASE_BACKUP and certain variants of CREATE_REPLICATION_SLOT. So they can trigger this panic if such a command is run while the shutdown checkpoint is being written. To fix this, divide the walsender shutdown into two phases. First, the postmaster sends a SIGUSR2 signal to all walsenders. The walsenders then put themselves into the "stopping" state. In this state, they reject any new commands. (For simplicity, we reject all new commands, so that in the future we do not have to track meticulously which commands might generate WAL.) The checkpointer waits for all walsenders to reach this state before proceeding with the shutdown checkpoint. After the shutdown checkpoint is done, the postmaster sends SIGINT (previously unused) to the walsenders. This triggers the existing shutdown behavior of sending out the shutdown checkpoint record and then terminating. Author: Michael Paquier <michael.paquier@gmail.com> Reported-by: Fujii Masao <masao.fujii@gmail.com>
* Fix pfree-of-already-freed-tuple when rescanning a GiST index-only scan.Tom Lane2017-05-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | GiST's getNextNearest() function attempts to pfree the previously-returned tuple if any (that is, scan->xs_hitup in HEAD, or scan->xs_itup in older branches). However, if we are rescanning a plan node after ending a previous scan early, those tuple pointers could be pointing to garbage, because they would be pointing into the scan's pageDataCxt or queueCxt which has been reset. In a debug build this reliably results in a crash, although I think it might sometimes accidentally fail to fail in production builds. To fix, clear the pointer field anyplace we reset a context it might be pointing into. This may be overkill --- I think probably only the queueCxt case is involved in this bug, so that resetting in gistrescan() would be sufficient --- but dangling pointers are generally bad news, so let's avoid them. Another plausible answer might be to just not bother with the pfree in getNextNearest(). The reconstructed tuples would go away anyway in the context resets, and I'm far from convinced that freeing them a bit earlier really saves anything meaningful. I'll stick with the original logic in this patch, but if we find more problems in the same area we should consider that approach. Per bug #14641 from Denis Smirnov. Back-patch to 9.5 where this logic was introduced. Discussion: https://postgr.es/m/20170504072034.24366.57688@wrigleys.postgresql.org
* Fix logical replication launcher wake up and resetPeter Eisentraut2017-05-01
| | | | | | | | | | | | | After the logical replication launcher was told to wake up at commit (for example, by a CREATE SUBSCRIPTION command), the flag to wake up was not reset, so it would be woken up at every following commit as well. So fix that by resetting the flag. Also, we don't need to wake up anything if the transaction was rolled back. Just reset the flag in that case. Author: Masahiko Sawada <sawada.mshk@gmail.com> Reported-by: Fujii Masao <masao.fujii@gmail.com>
* Rework handling of subtransactions in 2PC recoverySimon Riggs2017-04-27
| | | | | | | | | | | | | | The bug fixed by 0874d4f3e183757ba15a4b3f3bf563e0393dd9c2 caused us to question and rework the handling of subtransactions in 2PC during and at end of recovery. Patch adds checks and tests to ensure no further bugs. This effectively removes the temporary measure put in place by 546c13e11b29a5408b9d6a6e3cca301380b47f7f. Author: Simon Riggs Reviewed-by: Tom Lane, Michael Paquier Discussion: http://postgr.es/m/CANP8+j+vvXmruL_i2buvdhMeVv5TQu0Hm2+C5N+kdVwHJuor8w@mail.gmail.com
* Workaround for RecoverPreparedTransactions()Simon Riggs2017-04-23
| | | | | | Force overwriteOK = true while we investigate deeper fix Proposed by Tom Lane as temporary measure, accepted by me
* Fix order of arguments to SubTransSetParent().Tom Lane2017-04-23
| | | | | | | | | | | | | | ProcessTwoPhaseBuffer (formerly StandbyRecoverPreparedTransactions) mixed up the parent and child XIDs when calling SubTransSetParent to record the transactions' relationship in pg_subtrans. Remarkably, analysis by Simon Riggs suggests that this doesn't lead to visible problems (at least, not in non-Assert builds). That might explain why we'd not noticed it before. Nonetheless, it's surely wrong. This code was born broken, so back-patch to all supported branches. Discussion: https://postgr.es/m/20110.1492905318@sss.pgh.pa.us
* Exit correctly from PrepareRedoRemove() when not foundSimon Riggs2017-04-18
| | | | | | | | | Complex crash bug all started with this failure. Diagnosed and fixed by Nikhil Sontakke, reviewed by me. Reported-by: Jeff Janes Author: Nikhil Sontakke Discussion: https://postgr.es/m/CAMkU=1xBP8cqdS5eK8APHL=X6RHMMM2vG5g+QamduuTsyCwv9g@mail.gmail.com
* Don’t push nextid too far forwards in recoverySimon Riggs2017-04-18
| | | | | | | | | | | | | | Doing so allows various crash possibilities. Fix by avoiding having PrescanPreparedTransactions() increment ShmemVariableCache->nextXid when it has no 2PC files Bug found by Jeff Janes, diagnosis and patch by Pavan Deolasee, then patch re-designed for clarity and full accuracy by Michael Paquier. Reported-by: Jeff Janes Author: Pavan Deolasee, Michael Paquier Discussion: https://postgr.es/m/CAMkU=1zMLnH_i1-PVQ-biZzvNx7VcuatriquEnh7HNk6K8Ss3Q@mail.gmail.com
* Fix new warnings from GCC 7Peter Eisentraut2017-04-17
| | | | | This addresses the new warning types -Wformat-truncation -Wformat-overflow that are part of -Wall, via -Wformat, in GCC 7.
* Ensure BackgroundWorker struct contents are well-defined.Tom Lane2017-04-16
| | | | | | | | Coverity complained because bgw.bgw_extra wasn't being filled in by ApplyLauncherRegister(). The most future-proof fix is to memset the whole BackgroundWorker struct to zeroes. While at it, let's apply the same coding rule to other places that set up BackgroundWorker structs; four out of five had the same or related issues.
* Fix typo in commentPeter Eisentraut2017-04-16
| | | | Author: Masahiko Sawada <sawada.mshk@gmail.com>
* More cleanup of manipulations of hash indexes' hasho_flag field.Tom Lane2017-04-15
| | | | | | | Not much point in defining test macros for the flag bits if we don't use 'em. Amit Kapila
* 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
* Clean up manipulations of hash indexes' hasho_flag field.Tom Lane2017-04-14
| | | | | | | | | | | | | | | | | | | | | | | | Standardize on testing a hash index page's type by doing (opaque->hasho_flag & LH_PAGE_TYPE) == LH_xxx_PAGE Various places were taking shortcuts like opaque->hasho_flag & LH_BUCKET_PAGE which while not actually wrong, is still bad practice because it encourages use of opaque->hasho_flag & LH_UNUSED_PAGE which *is* wrong (LH_UNUSED_PAGE == 0, so the above is constant false). hash_xlog.c's hash_mask() contained such an incorrect test. This also ensures that we mask out the additional flag bits that hasho_flag has accreted since 9.6. pgstattuple's pgstat_hash_page(), for one, was failing to do that and was thus actively broken. Also fix assorted comments that hadn't been updated to reflect the extended usage of hasho_flag, and fix some macros that were testing just "(hasho_flag & bit)" to use the less dangerous, project-approved form "((hasho_flag & bit) != 0)". Coverity found the bug in hash_mask(); I noted the one in pgstat_hash_page() through code reading.
* Reduce the number of pallocs() in BRINAlvaro Herrera2017-04-07
| | | | | | | | | | Instead of allocating memory in brin_deform_tuple and brin_copy_tuple over and over during a scan, allow reuse of previously allocated memory. This is said to make for a measurable performance improvement. Author: Jinyu Zhang, Álvaro Herrera Reviewed by: Tomas Vondra Discussion: https://postgr.es/m/495deb78.4186.1500dacaa63.Coremail.beijing_pg@163.com
* Fix new BRIN desummarize WAL recordAlvaro Herrera2017-04-07
| | | | | | | | | | | | | The WAL-writing piece was forgetting to set the pages-per-range value. Also, fix the declared type of struct member heapBlk, which I mistakenly set as OffsetNumber rather than BlockNumber. Problem was introduced by commit c655899ba9ae (April 1st). Any system that tries to replay the new WAL record written before this fix is likely to die on replay and require pg_resetwal. Reported by Tom Lane. Discussion: https://postgr.es/m/20191.1491524824@sss.pgh.pa.us
* Clean up after insufficiently-researched optimization of tuple conversions.Tom Lane2017-04-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tupconvert.c's functions formerly considered that an explicit tuple conversion was necessary if the input and output tupdescs contained different type OIDs. The point of that was to make sure that a composite datum resulting from the conversion would contain the destination rowtype OID in its composite-datum header. However, commit 3838074f8 entirely misunderstood what that check was for, thinking that it had something to do with presence or absence of an OID column within the tuple. Removal of the check broke the no-op conversion path in ExecEvalConvertRowtype, as reported by Ashutosh Bapat. It turns out that of the dozen or so call sites for tupconvert.c functions, ExecEvalConvertRowtype is the only one that cares about the composite-datum header fields in the output tuple. In all the rest, we'd much rather avoid an unnecessary conversion whenever the tuples are physically compatible. Moreover, the comments in tupconvert.c only promise physical compatibility not a metadata match. So, let's accept the removal of the guarantee about the output tuple's rowtype marking, recognizing that this is a API change that could conceivably break third-party callers of tupconvert.c. (So, let's remember to mention it in the v10 release notes.) However, commit 3838074f8 did have a bit of a point here, in that two tuples mustn't be considered physically compatible if one has HEAP_HASOID set and the other doesn't. (Some of the callers of tupconvert.c might not really care about that, but we can't assume it in general.) The previous check accidentally covered that issue, because no RECORD types ever have OIDs, while if two tupdescs have the same named composite type OID then, a fortiori, they have the same tdhasoid setting. If we're removing the type OID match check then we'd better include tdhasoid match as part of the physical compatibility check. Without that hack in tupconvert.c, we need ExecEvalConvertRowtype to take responsibility for inserting the correct rowtype OID label whenever tupconvert.c decides it need not do anything. This is easily done with heap_copy_tuple_as_datum, which will be considerably faster than a tuple disassembly and reassembly anyway; so from a performance standpoint this change is a win all around compared to what happened in earlier branches. It just means a couple more lines of code in ExecEvalConvertRowtype. Ashutosh Bapat and Tom Lane Discussion: https://postgr.es/m/CAFjFpRfvHABV6+oVvGcshF8rHn+1LfRUhj7Jz1CDZ4gPUwehBg@mail.gmail.com
* Fix BRIN cost estimationAlvaro Herrera2017-04-06
| | | | | | | | | | | The original code was overly optimistic about the cost of scanning a BRIN index, leading to BRIN indexes being selected when they'd be a worse choice than some other index. This complete rewrite should be more accurate. Author: David Rowley, based on an earlier patch by Emre Hasegeli Reviewed-by: Emre Hasegeli Discussion: https://postgr.es/m/CAKJS1f9n-Wapop5Xz1dtGdpdqmzeGqQK4sV2MK-zZugfC14Xtw@mail.gmail.com
* Fix mixup of bool and ternary valuePeter Eisentraut2017-04-06
| | | | | | | Not currently a problem, but could be with stricter bool behavior under stdbool or C++. Reviewed-by: Andres Freund <andres@anarazel.de>
* Always SnapshotResetXmin() during ClearTransaction()Simon Riggs2017-04-06
| | | | Avoid corner cases during 2PC with 6bad580d9e678a0b604883e14d8401d469b06566
* Identity columnsPeter Eisentraut2017-04-06
| | | | | | | | | | | | | This is the SQL standard-conforming variant of PostgreSQL's serial columns. It fixes a few usability issues that serial columns have: - CREATE TABLE / LIKE copies default but refers to same sequence - cannot add/drop serialness with ALTER TABLE - dropping default does not drop sequence - need to grant separate privileges to sequence - other slight weirdnesses because serial is some kind of special macro Reviewed-by: Vitaly Burovoy <vitaly.burovoy@gmail.com>
* Avoid SnapshotResetXmin() during AtEOXact_Snapshot()Simon Riggs2017-04-06
| | | | | | | | | | | | | | | | | | | For normal commits and aborts we already reset PgXact->xmin, so we can simply avoid running SnapshotResetXmin() twice. During performance tests by Alexander Korotkov, diagnosis by Andres Freund showed PgXact array as a bottleneck. After manual analysis by me of the code paths that touch those memory locations, I was able to identify extraneous code in the main transaction commit path. Avoiding touching highly contented shmem improves concurrent performance slightly on all workloads, confirmed by tests run by Ashutosh Sharma and Alexander Korotkov. Simon Riggs Discussion: CANP8+jJdXE9b+b9F8CQT-LuxxO0PBCB-SZFfMVAdp+akqo4zfg@mail.gmail.com
* Fix pageinspect failures on hash indexes.Robert Haas2017-04-05
| | | | | | | | | | | | | | Make every page in a hash index which isn't all-zeroes have a valid special space, so that tools like pageinspect don't error out. Also, make pageinspect cope with all-zeroes pages, because _hash_alloc_buckets can leave behind large numbers of those until they're consumed by splits. Ashutosh Sharma and Robert Haas, reviewed by Amit Kapila. Original trouble report from Jeff Janes. Discussion: http://postgr.es/m/CAMkU=1y6NjKmqbJ8wLMhr=F74WzcMALYWcVFhEpm7i=mV=XsOg@mail.gmail.com
* hash: Fix write-ahead logging bug.Robert Haas2017-04-05
| | | | | | | | | | The size of the data is not the same thing as the size of the size of the data. Reported off-list by Tushar Ahuja. Fix by Ashutosh Sharma, reviewed by Amit Kapila. Discussion: http://postgr.es/m/CAE9k0PnmPDXfvf8HDObme7q_Ewc4E26ukHXUBPySoOs0ObqqaQ@mail.gmail.com
* Capitalize names of PLs consistentlyPeter Eisentraut2017-04-05
| | | | Author: Daniel Gustafsson <daniel@yesql.se>
* Make min_wal_size/max_wal_size use MB internallySimon Riggs2017-04-04
| | | | | | | | | Previously they were defined using multiples of XLogSegSize. Remove GUC_UNIT_XSEGS. Introduce GUC_UNIT_MB Extracted from patch series on XLogSegSize infrastructure. Beena Emerson
* Fix uninitialized variables in twophase.cSimon Riggs2017-04-04
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* Speedup 2PC recovery by skipping two phase state files in normal pathSimon Riggs2017-04-04
| | | | | | | | | | | 2PC state info held in shmem at PREPARE, then cleaned at COMMIT PREPARED/ABORT PREPARED, avoiding writing/fsyncing any state information to disk in the normal path, greatly enhancing replay speed. Prepared transactions that live past one checkpoint redo horizon will be written to disk as now. Similar conceptually to 978b2f65aa1262eb4ecbf8b3785cb1b9cf4db78e and building upon the infrastructure created by that commit. Authors, in equal measure: Stas Kelvich, Nikhil Sontakke and Michael Paquier Discussion: https://postgr.es/m/CAMGcDxf8Bn9ZPBBJZba9wiyQq-Qk5uqq=VjoMnRnW5s+fKST3w@mail.gmail.com
* Fix formula in _hash_spareindex.Robert Haas2017-04-04
| | | | | | | | | | This was correct in earlier versions of the patch that lead to commit ea69a0dead5128c421140dc53fac165ba4af8520, but somehow got broken in the last version which I actually committed. Mithun Cy, per an off-list report from Ashutosh Sharma Discussion: http://postgr.es/m/CAD__OujbAwNU71v1y-RoQxZ8LZ6-V2UFTkex3v34MK6uZ3Xb5w@mail.gmail.com
* Expand hash indexes more gradually.Robert Haas2017-04-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | Since hash indexes typically have very few overflow pages, adding a new splitpoint essentially doubles the on-disk size of the index, which can lead to large and abrupt increases in disk usage (and perhaps long delays on occasion). To mitigate this problem to some degree, divide larger splitpoints into four equal phases. This means that, for example, instead of growing from 4GB to 8GB all at once, a hash index will now grow from 4GB to 5GB to 6GB to 7GB to 8GB, which is perhaps still not as smooth as we'd like but certainly an improvement. This changes the on-disk format of the metapage, so bump HASH_VERSION from 2 to 3. This will force a REINDEX of all existing hash indexes, but that's probably a good idea anyway. First, hash indexes from pre-10 versions of PostgreSQL could easily be corrupted, and we don't want to confuse corruption carried over from an older release with any corruption caused despite the new write-ahead logging in v10. Second, it will let us remove some backward-compatibility code added by commit 293e24e507838733aba4748b514536af2d39d7f2. Mithun Cy, reviewed by Amit Kapila, Jesper Pedersen and me. Regression test outputs updated by me. Discussion: http://postgr.es/m/CAD__OuhG6F1gQLCgMQNnMNgoCvOLQZz9zKYJQNYvYmmJoM42gA@mail.gmail.com Discussion: http://postgr.es/m/CA+TgmoYty0jCf-pa+m+vYUJ716+AxM7nv_syvyanyf5O-L_i2A@mail.gmail.com
* Properly acquire buffer lock for page-at-a-time hash vacuum.Robert Haas2017-04-03
| | | | | | | | | In a couple of places, _hash_kill_items was mistakenly called with the buffer lock not held. Repair. Ashutosh Sharma, per a report from Andreas Seltenreich Discussion: http://postgr.es/m/87o9wo8o0j.fsf@credativ.de
* BRIN de-summarizationAlvaro Herrera2017-04-01
| | | | | | | | | | | | | | When the BRIN summary tuple for a page range becomes too "wide" for the values actually stored in the table (because the tuples that were present originally are no longer present due to updates or deletes), it can be useful to remove the outdated summary tuple, so that a future summarization can install a tighter summary. This commit introduces a SQL-callable interface to do so. Author: Álvaro Herrera Reviewed-by: Eiji Seki Discussion: https://postgr.es/m/20170228045643.n2ri74ara4fhhfxf@alvherre.pgsql
* BRIN auto-summarizationAlvaro Herrera2017-04-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, only VACUUM would cause a page range to get initially summarized by BRIN indexes, which for some use cases takes too much time since the inserts occur. To avoid the delay, have brininsert request a summarization run for the previous range as soon as the first tuple is inserted into the first page of the next range. Autovacuum is in charge of processing these requests, after doing all the regular vacuuming/ analyzing work on tables. This doesn't impose any new tasks on autovacuum, because autovacuum was already in charge of doing summarizations. The only actual effect is to change the timing, i.e. that it occurs earlier. For this reason, we don't go any great lengths to record these requests very robustly; if they are lost because of a server crash or restart, they will happen at a later time anyway. Most of the new code here is in autovacuum, which can now be told about "work items" to process. This can be used for other things such as GIN pending list cleaning, perhaps visibility map bit setting, both of which are currently invoked during vacuum, but do not really depend on vacuum taking place. The requests are at the page range level, a granularity for which we did not have SQL-level access; we only had index-level summarization requests via brin_summarize_new_values(). It seems reasonable to add SQL-level access to range-level summarization too, so add a function brin_summarize_range() to do that. Authors: Álvaro Herrera, based on sketch from Simon Riggs. Reviewed-by: Thomas Munro. Discussion: https://postgr.es/m/20170301045823.vneqdqkmsd4as4ds@alvherre.pgsql
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