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* Handle elog(FATAL) during ROLLBACK more robustly.Tom Lane2017-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stress testing by Andreas Seltenreich disclosed longstanding problems that occur if a FATAL exit (e.g. due to receipt of SIGTERM) occurs while we are trying to execute a ROLLBACK of an already-failed transaction. In such a case, xact.c is in TBLOCK_ABORT state, so that AbortOutOfAnyTransaction would skip AbortTransaction and go straight to CleanupTransaction. This led to an assert failure in an assert-enabled build (due to the ROLLBACK's portal still having a cleanup hook) or without assertions, to a FATAL exit complaining about "cannot drop active portal". The latter's not disastrous, perhaps, but it's messy enough to want to improve it. We don't really want to run all of AbortTransaction in this code path. The minimum required to clean up the open portal safely is to do AtAbort_Memory and AtAbort_Portals. It seems like a good idea to do AtAbort_Memory unconditionally, to be entirely sure that we are starting with a safe CurrentMemoryContext. That means that if the main loop in AbortOutOfAnyTransaction does nothing, we need an extra step at the bottom to restore CurrentMemoryContext = TopMemoryContext, which I chose to do by invoking AtCleanup_Memory. This'll result in calling AtCleanup_Memory twice in many of the paths through this function, but that seems harmless and reasonably inexpensive. The original motivation for the assertion in AtCleanup_Portals was that we wanted to be sure that any user-defined code executed as a consequence of the cleanup hook runs during AbortTransaction not CleanupTransaction. That still seems like a valid concern, and now that we've seen one case of the assertion firing --- which means that exactly that would have happened in a production build --- let's replace the Assert with a runtime check. If we see the cleanup hook still set, we'll emit a WARNING and just drop the hook unexecuted. This has been like this a long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/877ey7bmun.fsf@ansel.ydns.eu
* Remove AtEOXact_CatCache().Tom Lane2017-08-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sole useful effect of this function, to check that no catcache entries have positive refcounts at transaction end, has really been obsolete since we introduced ResourceOwners in PG 8.1. We reduced the checks to assertions years ago, so that the function was a complete no-op in production builds. There have been previous discussions about removing it entirely, but consensus up to now was that it had some small value as a cross-check for bugs in the ResourceOwner logic. However, it now emerges that it's possible to trigger these assertions if you hit an assert-enabled backend with SIGTERM during a call to SearchCatCacheList, because that function temporarily increases the refcounts of entries it's intending to add to a catcache list construct. In a normal ERROR scenario, the extra refcounts are cleaned up by SearchCatCacheList's PG_CATCH block; but in a FATAL exit we do a transaction abort and exit without ever executing PG_CATCH handlers. There's a case to be made that this is a generic hazard and we should consider restructuring elog(FATAL) handling so that pending PG_CATCH handlers do get run. That's pretty scary though: it could easily create more problems than it solves. Preliminary stress testing by Andreas Seltenreich suggests that there are not many live problems of this ilk, so we rejected that idea. There are more-localized ways to fix the problem; the most principled one would be to use PG_ENSURE_ERROR_CLEANUP instead of plain PG_TRY. But adding cycles to SearchCatCacheList isn't very appealing. We could also weaken the assertions in AtEOXact_CatCache in some more or less ad-hoc way, but that just makes its raison d'etre even less compelling. In the end, the most reasonable solution seems to be to just remove AtEOXact_CatCache altogether, on the grounds that it's not worth trying to fix it. It hasn't found any bugs for us in many years. Per report from Jeevan Chalke. Back-patch to all supported branches. Discussion: https://postgr.es/m/CAM2+6=VEE30YtRQCZX7_sCFsEpoUkFBV1gZazL70fqLn8rcvBA@mail.gmail.com
* Reword some unclear commentsAlvaro Herrera2017-08-08
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* Fix concurrent locking of tuple update chainAlvaro Herrera2017-07-26
| | | | | | | | | | | | | | | | | | | If several sessions are concurrently locking a tuple update chain with nonconflicting lock modes using an old snapshot, and they all succeed, it may happen that some of them fail because of restarting the loop (due to a concurrent Xmax change) and getting an error in the subsequent pass while trying to obtain a tuple lock that they already have in some tuple version. This can only happen with very high concurrency (where a row is being both updated and FK-checked by multiple transactions concurrently), but it's been observed in the field and can have unpleasant consequences such as an FK check failing to see a tuple that definitely exists: ERROR: insert or update on table "child_table" violates foreign key constraint "fk_constraint_name" DETAIL: Key (keyid)=(123456) is not present in table "parent_table". (where the key is observably present in the table). Discussion: https://postgr.es/m/20170714210011.r25mrff4nxjhmf3g@alvherre.pgsql
* Fix double shared memory allocation.Teodor Sigaev2017-07-21
| | | | | | | | | | | SLRU buffer lwlocks are allocated twice by oversight in commit fe702a7b3f9f2bc5bf6d173166d7d55226af82c8 where that locks were moved to separate tranche. The bug doesn't have user-visible effects except small overspending of shared memory. Backpatch to 9.6 where it was introduced. Alexander Korotkov with small editorization by me.
* Fix potential data corruption during freezeTeodor Sigaev2017-07-06
| | | | | | | Fix oversight in 3b97e6823b94 bug fix. Bitwise AND is used instead of OR and it cleans all bits in t_infomask heap tuple field. Backpatch to 9.3
* Fix typo in commentAlvaro Herrera2017-06-22
| | | | | | | | Once upon a time, WAL pointers could be NULL, but no longer. We talk about "valid" now. Reported-by: Amit Langote Discussion: https://postgr.es/m/33e9617d-27f1-eee8-3311-e27af98eaf2b@lab.ntt.co.jp
* Fix possibility of creating a "phantom" segment after promotion.Andres Freund2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When promoting a standby just after a XLOG_SWITCH record was replayed, and next segment(s) are already are locally available (via walsender, restore_command + trigger/recovery target), that segment could accidentally be recycled onto the past of the new timeline. Later checkpointer would create a .ready file for it, assuming there was an error during creation, and it would get archived. That causes trouble if another standby is later brought up from a basebackup from before the timeline creation, because it would try to read the segment, because XLogFileReadAnyTLI just tries all possible timelines, which doesn't have valid contents. Thus replay would fail. The problem, if already occurred, can be fixed by removing the segment and/or having restore_command filter it out. The reason for the creation of such "phantom" segments was, that after an XLOG_SWITCH record the EndOfLog variable points to the beginning of the next segment, and RemoveXlogFile() used XLByteToPrevSeg(). Normally RemoveXlogFile() doing so is harmless, because the last segment will still exist preventing InstallXLogFileSegment() from causing harm, but just after promotion there's no previous segment on the new timeline. Fix that by using XLByteToSeg() instead of XLByteToPrevSeg(). Author: Andres Freund Reported-By: Greg Burek Discussion: https://postgr.es/m/20170619073026.zcwpe6mydsaz5ygd@alap3.anarazel.de Backpatch: 9.2-, bug older than all supported versions
* 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
* Assorted translatable string fixesAlvaro Herrera2017-06-04
| | | | | Mark our rusage reportage string translatable; remove quotes from type names; unify formatting of very similar messages.
* 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 new warnings from GCC 7Peter Eisentraut2017-05-16
| | | | | This addresses the new warning types -Wformat-truncation -Wformat-overflow that are part of -Wall, via -Wformat, in GCC 7.
* 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 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
* Avoid passing function pointers across process boundaries.Tom Lane2017-04-15
| | | | | | | | | | | | This back-patches commit 32470825d36d99a81347ee36c181d609c952c061 into 9.6, primarily to make buildfarm member culicidae happy. Unlike the HEAD patch, avoid changing the existing API of CreateParallelContext; instead we just switch to using CreateParallelContextForExternalFunction, even for core functions. 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
* Suppress implicit-conversion warnings seen with newer clang versions.Tom Lane2017-03-28
| | | | | | | | | | | | | | | We were assigning values near 255 through "char *" pointers. On machines where char is signed, that's not entirely kosher, and it's reasonable for compilers to warn about it. A better solution would be to change the pointer type to "unsigned char *", but that would be vastly more invasive. For the moment, let's just apply this simple backpatchable solution. Aleksander Alekseev Discussion: https://postgr.es/m/20170220141239.GD12278@e733.localdomain Discussion: https://postgr.es/m/2839.1490714708@sss.pgh.pa.us
* Fix backup cancelingTeodor Sigaev2017-03-24
| | | | | | | | | | | | | | | | | Assert-enabled build crashes but without asserts it works by wrong way: it may not reset forcing full page write and preventing from starting exclusive backup with the same name as cancelled. Patch replaces pair of booleans nonexclusive_backup_running/exclusive_backup_running to single enum to correctly describe backup state. Backpatch to 9.6 where bug was introduced Reported-by: David Steele Authors: Michael Paquier, David Steele Reviewed-by: Anastasia Lubennikova https://commitfest.postgresql.org/13/1068/
* Spelling fixesPeter Eisentraut2017-03-14
| | | | From: Josh Soref <jsoref@gmail.com>
* Fix incorrect variable datatypeMagnus Hagander2017-02-28
| | | | | | | Both datatypes map to the same underlying one which is why it still worked, but we should use the correct type. Author: Kyotaro HORIGUCHI
* Fix typos in comments.Heikki Linnakangas2017-02-06
| | | | | | | | | Backpatch to all supported versions, where applicable, to make backpatching of future fixes go more smoothly. Josh Soref Discussion: https://www.postgresql.org/message-id/CACZqfqCf+5qRztLPgmmosr-B0Ye4srWzzw_mo4c_8_B_mtjmJQ@mail.gmail.com
* Don't count background workers against a user's connection limit.Andrew Dunstan2017-02-01
| | | | | | | | | | Doing so doesn't seem to be within the purpose of the per user connection limits, and has particularly unfortunate effects in conjunction with parallel queries. Backpatch to 9.6 where parallel queries were introduced. David Rowley, reviewed by Robert Haas and Albe Laurenz.
* Fix an assertion failure related to an exclusive backup.Fujii Masao2017-01-17
| | | | | | | | | | | | | | | | | | | | | | Previously multiple sessions could execute pg_start_backup() and pg_stop_backup() to start and stop an exclusive backup at the same time. This could trigger the assertion failure of "FailedAssertion("!(XLogCtl->Insert.exclusiveBackup)". This happend because, even while pg_start_backup() was starting an exclusive backup, other session could run pg_stop_backup() concurrently and mark the backup as not-in-progress unconditionally. This patch introduces ExclusiveBackupState indicating the state of an exclusive backup. This state is used to ensure that there is only one session running pg_start_backup() or pg_stop_backup() at the same time, to avoid the assertion failure. Back-patch to all supported versions. Author: Michael Paquier Reviewed-By: Kyotaro Horiguchi and me Reported-By: Andreas Seltenreich Discussion: <87mvktojme.fsf@credativ.de>
* Fix ALTER TABLE / SET TYPE for irregular inheritanceAlvaro Herrera2017-01-09
| | | | | | | | | | | | | | | | | | | If inherited tables don't have exactly the same schema, the USING clause in an ALTER TABLE / SET DATA TYPE misbehaves when applied to the children tables since commit 9550e8348b79. Starting with that commit, the attribute numbers in the USING expression are fixed during parse analysis. This can lead to bogus errors being reported during execution, such as: ERROR: attribute 2 has wrong type DETAIL: Table has type smallint, but query expects integer. Since it wouldn't do to revert to the original coding, we now apply a transformation to map the attribute numbers to the correct ones for each child. Reported by Justin Pryzby Analysis by Tom Lane; patch by me. Discussion: https://postgr.es/m/20170102225618.GA10071@telsasoft.com
* BRIN revmap pages are not standard pages ...Alvaro Herrera2017-01-09
| | | | | | | | | | | | | | | | | | | | | | | | ... and therefore we ought not to tell XLogRegisterBuffer the opposite, when writing XLog for a brin update that moves the index tuple to a different page. Otherwise, xlog insertion would try to "compress the hole" when producing a full-page image for it; but since we don't update pd_lower/upper, the hole covers the whole page. On WAL replay, the revmap page becomes empty and so the entire portion of the index is useless and needs to be recomputed. This is low-probability: a BRIN update only moves an index tuple to a different page when the summary tuple is larger than the existing one, which doesn't happen with fixed-width datatypes. Also, the revmap page must be first after a checkpoint. Report and patch: Kuntal Ghosh Bug is alleged to have detected by a WAL-consistency-checking tool. Discussion: https://postgr.es/m/CAGz5QCJ=00UQjScSEFbV=0qO5ShTZB9WWz_Fm7+Wd83zPs9Geg@mail.gmail.com I posted a test case demonstrating the problem, but I'm refraining from adding it to the test suite; if the WAL consistency tool makes it in, that will be a better way to catch this from regressing. (We should definitely have someting that causes not-same-page updates, though.)
* Remove triggerable Assert in hashname().Tom Lane2016-12-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hashname() asserted that the key string it is given is shorter than NAMEDATALEN. That should surely always be true if the input is in fact a regular value of type "name". However, for reasons of coding convenience, we allow plain old C strings to be treated as "name" values in many places. Some SQL functions accept arbitrary "text" inputs, convert them to C strings, and pass them otherwise-untransformed to syscache lookups for name columns, allowing an overlength input value to trigger hashname's Assert. This would be a DOS problem, except that it only happens in assert-enabled builds which aren't recommended for production. In a production build, you'll just get a name lookup error, since regardless of the hash value computed by hashname, the later equality comparison checks can't match. Likewise, if the catalog lookup is done by seqscan or indexscan searches, there will just be a lookup error, since the name comparison functions don't contain any similar length checks, and will see an overlength input as unequal to any stored entry. After discussion we concluded that we should simply remove this Assert. It's inessential to hashname's own functionality, and having such an assertion in only some paths for name lookup is more of a foot-gun than a useful check. There may or may not be a case for the affected callers to do something other than let the name lookup fail, but we'll consider that separately; in any case we probably don't want to change such behavior in the back branches. Per report from Tushar Ahuja. Back-patch to all supported branches. Report: https://postgr.es/m/7d0809ee-6f25-c9d6-8e74-5b2967830d49@enterprisedb.com Discussion: https://postgr.es/m/17691.1482523168@sss.pgh.pa.us
* Fix broken error check in _hash_doinsert.Robert Haas2016-12-22
| | | | | | | | | | | | You can't just cast a HashMetaPage to a Page, because the meta page data is stored after the page header, not at offset 0. Fortunately, this didn't break anything because it happens to find hashm_bsize at the offset at which it expects to find pd_pagesize_version, and the values are close enough to the same that this works out. Still, it's a bug, so back-patch to all supported versions. Mithun Cy, revised a bit by me.
* Log the creation of an init fork unconditionally.Robert Haas2016-12-08
| | | | | | | | | | | | | | | | | Previously, it was thought that this only needed to be done for the benefit of possible standbys, so wal_level = minimal skipped it. But that's not safe, because during crash recovery we might replay XLOG_DBASE_CREATE or XLOG_TBLSPC_CREATE record which recursively removes the directory that contains the new init fork. So log it always. The user-visible effect of this bug is that if you create a database or tablespace, then create an unlogged table, then crash without checkpointing, then restart, accessing the table will fail, because the it won't have been properly reset. This commit fixes that. Michael Paquier, per a report from Konstantin Knizhnik. Wording of the comments per a suggestion from me.
* Revert "Permit dump/reload of not-too-large >1GB tuples"Alvaro Herrera2016-12-06
| | | | | | This reverts commit 4e01ecae98275298c680c92fdba62daf603dc98e. Per Tom Lane, changing the definition of StringInfoData amounts to an ABI break, which is unacceptable in back branches.
* Fix incorrect output from gin_desc().Fujii Masao2016-12-05
| | | | | | | | | | | | | | | | | | | | | Previously gin_desc() displayed incorrect output "unknown action 0" for XLOG_GIN_INSERT and XLOG_GIN_VACUUM_DATA_LEAF_PAGE records with valid actions. The cause of this problem was that gin_desc() wrongly used XLogRecGetData() to extract data from those records. Since they were registered by XLogRegisterBufData(), gin_desc() should have used XLogRecGetBlockData(), instead, like gin_redo(). Also there were other differences about how to treat XLOG_GIN_INSERT record between gin_desc() and gin_redo(). This commit fixes gin_desc() routine so that it treats those records in the same way as gin_redo(). Batch-patch to 9.5 where WAL record format was revamped and XLogRegisterBufData() was added. Reported-By: Andres Freund Reviewed-By: Tom Lane Discussion: <20160509194645.7lewnpw647zegx2m@alap3.anarazel.de>
* Permit dump/reload of not-too-large >1GB tuplesAlvaro Herrera2016-12-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our documentation states that our maximum field size is 1 GB, and that our maximum row size of 1.6 TB. However, while this might be attainable in theory with enough contortions, it is not workable in practice; for starters, pg_dump fails to dump tables containing rows larger than 1 GB, even if individual columns are well below the limit; and even if one does manage to manufacture a dump file containing a row that large, the server refuses to load it anyway. This commit enables dumping and reloading of such tuples, provided two conditions are met: 1. no single column is larger than 1 GB (in output size -- for bytea this includes the formatting overhead) 2. the whole row is not larger than 2 GB There are three related changes to enable this: a. StringInfo's API now has two additional functions that allow creating a string that grows beyond the typical 1GB limit (and "long" string). ABI compatibility is maintained. We still limit these strings to 2 GB, though, for reasons explained below. b. COPY now uses long StringInfos, so that pg_dump doesn't choke trying to emit rows longer than 1GB. c. heap_form_tuple now uses the MCXT_ALLOW_HUGE flag in its allocation for the input tuple, which means that large tuples are accepted on input. Note that at this point we do not apply any further limit to the input tuple size. The main reason to limit to 2 GB is that the FE/BE protocol uses 32 bit length words to describe each row; and because the documentation is ambiguous on its signedness and libpq does consider it signed, we cannot use the highest-order bit. Additionally, the StringInfo API uses "int" (which is 4 bytes wide in most platforms) in many places, so we'd need to change that API too in order to improve, which has lots of fallout. Backpatch to 9.5, which is the oldest that has MemoryContextAllocExtended, a necessary piece of infrastructure. We could apply to 9.4 with very minimal additional effort, but any further than that would require backpatching "huge" allocations too. This is the largest set of changes we could find that can be back-patched without breaking compatibility with existing systems. Fixing a bigger set of problems (for example, dumping tuples bigger than 2GB, or dumping fields bigger than 1GB) would require changing the FE/BE protocol and/or changing the StringInfo API in an ABI-incompatible way, neither of which would be back-patchable. Authors: Daniel Vérité, Álvaro Herrera Reviewed by: Tomas Vondra Discussion: https://postgr.es/m/20160229183023.GA286012@alvherre.pgsql
* Bring some clarity to the defaults for the xxx_flush_after parameters.Tom Lane2016-11-25
| | | | | | | | | | | | | | | | | | | | | | | | | | Instead of confusingly stating platform-dependent defaults for these parameters in the comments in postgresql.conf.sample (with the main entry being a lie on Linux), teach initdb to install the correct platform-dependent value in postgresql.conf, similarly to the way we handle other platform-dependent defaults. This won't do anything for existing 9.6 installations, but since it's effectively only a documentation improvement, that seems OK. Since this requires initdb to have access to the default values, move the #define's for those to pg_config_manual.h; the original placement in bufmgr.h is unworkable because that file can't be included by frontend programs. Adjust the default value for wal_writer_flush_after so that it is 1MB regardless of XLOG_BLCKSZ, conforming to what is stated in both the SGML docs and postgresql.conf. (We could alternatively make it scale with XLOG_BLCKSZ, but I'm not sure I see the point.) Copy-edit related SGML documentation. Fabien Coelho and Tom Lane, per a gripe from Tomas Vondra. Discussion: <30ebc6e3-8358-09cf-44a8-578252938424@2ndquadrant.com>
* Fix commit_ts for FrozenXid and BootstrapXidAlvaro Herrera2016-11-24
| | | | | | | | | | | | | | | | Previously, requesting commit timestamp for transactions FrozenTransactionId and BootstrapTransactionId resulted in an error. But since those values can validly appear in committed tuples' Xmin, this behavior is unhelpful and error prone: each caller would have to special-case those values before requesting timestamp data for an Xid. We already have a perfectly good interface for returning "the Xid you requested is too old for us to have commit TS data for it", so let's use that instead. Backpatch to 9.5, where commit timestamps appeared. Author: Craig Ringer Discussion: https://www.postgresql.org/message-id/CAMsr+YFM5Q=+ry3mKvWEqRTxrB0iU3qUSRnS28nz6FJYtBwhJg@mail.gmail.com
* Avoid pin scan for replay of XLOG_BTREE_VACUUM in all casesAlvaro Herrera2016-11-17
| | | | | | | | | | | | | | | | | | | | | | | Replay of XLOG_BTREE_VACUUM during Hot Standby was previously thought to require complex interlocking that matched the requirements on the master. This required an O(N) operation that became a significant problem with large indexes, causing replication delays of seconds or in some cases minutes while the XLOG_BTREE_VACUUM was replayed. This commit skips the “pin scan” that was previously required, by observing in detail when and how it is safe to do so, with full documentation. The pin scan is skipped only in replay; the VACUUM code path on master is not touched here. No tests included. Manual tests using an additional patch to view WAL records and their timing have shown the change in WAL records and their handling has successfully reduced replication delay. This is a back-patch of commits 687f2cd7a015, 3e4b7d87988f, b60284261375 by Simon Riggs, to branches 9.4 and 9.5. No further backpatch is possible because this depends on catalog scans being MVCC. I (Álvaro) additionally updated a slight problem in the README, which explains why this touches the 9.6 and master branches.
* Fix possible pg_basebackup failure on standby with "include WAL".Robert Haas2016-10-27
| | | | | | | | | | | | | | | If a restartpoint flushed no dirty buffers, it could fail to update the minimum recovery point, leading to a minimum recovery point prior to the starting REDO location. perform_base_backup() would interpret that as meaning that no WAL files at all needed to be included in the backup, failing an internal sanity check. To fix, have restartpoints always update the minimum recovery point to just after the checkpoint record itself, so that the file (or files) containing the checkpoint record will always be included in the backup. Code by Amit Kapila, per a design suggestion by me, with some additional work on the code comment by me. Test case by Michael Paquier. Report by Kyotaro Horiguchi.
* Preserve commit timestamps across clean restartAlvaro Herrera2016-10-24
| | | | | | | | | An oversight in setting the boundaries of known commit timestamps during startup caused old commit timestamps to become inaccessible after a server restart. Author and reporter: Julien Rouhaud Review, test code: Craig Ringer
* Fix WAL-logging of FSM and VM truncation.Heikki Linnakangas2016-10-19
| | | | | | | | | | | | | | | | | | | | | | | | | | When a relation is truncated, it is important that the FSM is truncated as well. Otherwise, after recovery, the FSM can return a page that has been truncated away, leading to errors like: ERROR: could not read block 28991 in file "base/16390/572026": read only 0 of 8192 bytes We were using MarkBufferDirtyHint() to dirty the buffer holding the last remaining page of the FSM, but during recovery, that might in fact not dirty the page, and the FSM update might be lost. To fix, use the stronger MarkBufferDirty() function. MarkBufferDirty() requires us to do WAL-logging ourselves, to protect from a torn page, if checksumming is enabled. Also fix an oversight in visibilitymap_truncate: it also needs to WAL-log when checksumming is enabled. Analysis by Pavan Deolasee. Discussion: <CABOikdNr5vKucqyZH9s1Mh0XebLs_jRhKv6eJfNnD2wxTn=_9A@mail.gmail.com> Backpatch to 9.3, where we got data checksums.
* Remove useless code.Tom Lane2016-09-23
| | | | | | | | | Apparent copy-and-pasteo in standby_desc_invalidations() had two entries for msg->id == SHAREDINVALRELMAP_ID. Aleksander Alekseev Discussion: <20160923090814.GB1238@e733>
* Fix outdated comments, GIST search queue is not an RBTree anymore.Heikki Linnakangas2016-09-20
| | | | | | The GiST search queue is implemented as a pairing heap rather than as Red-Black Tree, since 9.5 (commit e7032610). I neglected these comments in that commit.
* Fix locking a tuple updated by an aborted (sub)transactionAlvaro Herrera2016-09-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When heap_lock_tuple decides to follow the update chain, it tried to also lock any version of the tuple that was created by an update that was subsequently rolled back. This is pointless, since for all intents and purposes that tuple exists no more; and moreover it causes misbehavior, as reported independently by Marko Tiikkaja and Marti Raudsepp: some SELECT FOR UPDATE/SHARE queries may fail to return the tuples, and assertion-enabled builds crash. Fix by having heap_lock_updated_tuple test the xmin and return success immediately if the tuple was created by an aborted transaction. The condition where tuples become invisible occurs when an updated tuple chain is followed by heap_lock_updated_tuple, which reports the problem as HeapTupleSelfUpdated to its caller heap_lock_tuple, which in turn propagates that code outwards possibly leading the calling code (ExecLockRows) to believe that the tuple exists no longer. Backpatch to 9.3. Only on 9.5 and newer this leads to a visible failure, because of commit 27846f02c176; before that, heap_lock_tuple skips the whole dance when the tuple is already locked by the same transaction, because of the ancient HeapTupleSatisfiesUpdate behavior. Still, the buggy condition may also exist in more convoluted scenarios involving concurrent transactions, so it seems safer to fix the bug in the old branches too. Discussion: https://www.postgresql.org/message-id/CABRT9RC81YUf1=jsmWopcKJEro=VoeG2ou6sPwyOUTx_qteRsg@mail.gmail.com https://www.postgresql.org/message-id/48d3eade-98d3-8b9a-477e-1a8dc32a724d@joh.to
* Fix corruption of 2PC recovery with subxactsSimon Riggs2016-09-09
| | | | | | | | Reading 2PC state files during recovery was borked, causing corruptions during recovery. Effect limited to servers with 2PC, subtransactions and recovery/replication. Stas Kelvich, reviewed by Michael Paquier and Pavan Deolasee
* Fix minor memory leak in Standby startupSimon Riggs2016-09-08
| | | | | | | | | | StandbyRecoverPreparedTransactions() leaked the buffer used for two phase state file. This was leaked once at startup and at every shutdown checkpoint seen. Backpatch to 9.6 Stas Kelvich
* Fix corrupt GIN_SEGMENT_ADDITEMS WAL records on big-endian hardware.Tom Lane2016-09-03
| | | | | | | | | | | | | | | | | | | | computeLeafRecompressWALData() tried to produce a uint16 WAL log field by memcpy'ing the first two bytes of an int-sized variable. That accidentally works on little-endian hardware, but not at all on big-endian. Replay then thinks it's looking at an ADDITEMS action with zero entries, and reads the first two bytes of the first TID therein as the next segno/action, typically leading to "unexpected GIN leaf action" errors during replay. Even if replay failed to crash, the resulting GIN index page would surely be incorrect. To fix, just declare the variable as uint16 instead. Per bug #14295 from Spencer Thomason (much thanks to Spencer for turning his problem into a self-contained test case). This likely also explains a previous report of the same symptom from Bernd Helmle. Back-patch to 9.4 where the problem was introduced (by commit 14d02f0bb). Discussion: <20160826072658.15676.7628@wrigleys.postgresql.org> Possible-Report: <2DA7350F7296B2A142272901@eje.land.credativ.lan>
* Prevent starting a standalone backend with standby_mode on.Tom Lane2016-08-31
| | | | | | | | | | | | | | | | | | | This can't really work because standby_mode expects there to be more WAL arriving, which there will not ever be because there's no WAL receiver process to fetch it. Moreover, if standby_mode is on then hot standby might also be turned on, causing even more strangeness because that expects read-only sessions to be executing in parallel. Bernd Helmle reported a case where btree_xlog_delete_get_latestRemovedXid got confused, but rather than band-aiding individual problems it seems best to prevent getting anywhere near this state in the first place. Back-patch to all supported branches. In passing, also fix some omissions of errcodes in other ereport's in readRecoveryCommandFile(). Michael Paquier (errcode hacking by me) Discussion: <00F0B2CEF6D0CEF8A90119D4@eje.credativ.lan>
* Fix pg_xlogdump so that it handles cross-page XLP_FIRST_IS_CONTRECORD record.Fujii Masao2016-08-29
| | | | | | | | | | | | | | | | | | Previously pg_xlogdump failed to dump the contents of the WAL file if the file starts with the continuation WAL record which spans more than one pages. Since pg_xlogdump assumed that the continuation record always fits on a page, it could not find the valid WAL record to start reading from in that case. This patch changes pg_xlogdump so that it can handle a continuation WAL record which crosses a page boundary and find the valid record to start reading from. Back-patch to 9.3 where pg_xlogdump was introduced. Author: Pavan Deolasee Reviewed-By: Michael Paquier and Craig Ringer Discussion: CABOikdPsPByMiG6J01DKq6om2+BNkxHTPkOyqHM2a4oYwGKsqQ@mail.gmail.com
* Add macros to make AllocSetContextCreate() calls simpler and safer.Tom Lane2016-08-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I found that half a dozen (nearly 5%) of our AllocSetContextCreate calls had typos in the context-sizing parameters. While none of these led to especially significant problems, they did create minor inefficiencies, and it's now clear that expecting people to copy-and-paste those calls accurately is not a great idea. Let's reduce the risk of future errors by introducing single macros that encapsulate the common use-cases. Three such macros are enough to cover all but two special-purpose contexts; those two calls can be left as-is, I think. While this patch doesn't in itself improve matters for third-party extensions, it doesn't break anything for them either, and they can gradually adopt the simplified notation over time. In passing, change TopMemoryContext to use the default allocation parameters. Formerly it could only be extended 8K at a time. That was probably reasonable when this code was written; but nowadays we create many more contexts than we did then, so that it's not unusual to have a couple hundred K in TopMemoryContext, even without considering various dubious code that sticks other things there. There seems no good reason not to let it use growing blocks like most other contexts. Back-patch to 9.6, mostly because that's still close enough to HEAD that it's easy to do so, and keeping the branches in sync can be expected to avoid some future back-patching pain. The bugs fixed by these changes don't seem to be significant enough to justify fixing them further back. Discussion: <21072.1472321324@sss.pgh.pa.us>
* Fix potential memory leakage from HandleParallelMessages().Tom Lane2016-08-26
| | | | | | | | | | | | | | | | HandleParallelMessages leaked memory into the caller's context. Since it's called from ProcessInterrupts, there is basically zero certainty as to what CurrentMemoryContext is, which means we could be leaking into long-lived contexts. Over the processing of many worker messages that would grow to be a problem. Things could be even worse than just a leak, if we happened to service the interrupt while ErrorContext is current: elog.c thinks it can reset that on its own whim, possibly yanking storage out from under HandleParallelMessages. Give HandleParallelMessages its own dedicated context instead, which we can reset during each call to ensure there's no accumulation of wasted memory. Discussion: <16610.1472222135@sss.pgh.pa.us>
* Fix logic for adding "parallel worker" context line to worker errors.Tom Lane2016-08-26
| | | | | | | | | The previous coding here was capable of adding a "parallel worker" context line to errors that were not, in fact, returned from a parallel worker. Instead of using an errcontext callback to add that annotation, just paste it onto the message by hand; this looks uglier but is more reliable. Discussion: <19757.1472151987@sss.pgh.pa.us>
* Fix small query-lifespan memory leak in bulk updates.Tom Lane2016-08-24
| | | | | | | | | | | | | When there is an identifiable REPLICA IDENTITY index on the target table, heap_update leaks the id_attrs bitmapset. That's not many bytes, but it adds up over enough rows, since the code typically runs in a query-lifespan context. Bug introduced in commit e55704d8b, which did a rather poor job of cloning the existing use-pattern for RelationGetIndexAttrBitmap(). Per bug #14293 from Zhou Digoal. Back-patch to 9.4 where the bug was introduced. Report: <20160824114320.15676.45171@wrigleys.postgresql.org>
* Suppress compiler warnings in non-cassert builds.Tom Lane2016-08-23
| | | | | | With Asserts off, these variables are set but never used, resulting in warnings from pickier compilers. Fix that with our standard solution. Per report from Jeff Janes.