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* Fix assorted bugs in CREATE INDEX CONCURRENTLY.Tom Lane2012-11-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch changes CREATE INDEX CONCURRENTLY so that the pg_index flag changes it makes without exclusive lock on the index are made via heap_inplace_update() rather than a normal transactional update. The latter is not very safe because moving the pg_index tuple could result in concurrent SnapshotNow scans finding it twice or not at all, thus possibly resulting in index corruption. In addition, fix various places in the code that ought to check to make sure that the indexes they are manipulating are valid and/or ready as appropriate. These represent bugs that have existed since 8.2, since a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid index behind, and we ought not try to do anything that might fail with such an index. Also fix RelationReloadIndexInfo to ensure it copies all the pg_index columns that are allowed to change after initial creation. Previously we could have been left with stale values of some fields in an index relcache entry. It's not clear whether this actually had any user-visible consequences, but it's at least a bug waiting to happen. This is a subset of a patch already applied in 9.2 and HEAD. Back-patch into all earlier supported branches. Tom Lane and Andres Freund
* Avoid bogus "out-of-sequence timeline ID" errors in standby-mode.Heikki Linnakangas2012-11-22
| | | | | | | | | | | | | | | | | | When startup process opens a WAL segment after replaying part of it, it validates the first page on the WAL segment, even though the page it's really interested in later in the file. As part of the validation, it checks that the TLI on the page header is >= the TLI it saw on the last page it read. If the segment contains a timeline switch, and we have already replayed it, and then re-open the WAL segment (because of streaming replication got disconnected and reconnected, for example), the TLI check will fail when the first page is validated. Fix that by relaxing the TLI check when re-opening a WAL segment. Backpatch to 9.0. Earlier versions had the same code, but before standby mode was introduced in 9.0, recovery never tried to re-read a segment after partially replaying it. Reported by Amit Kapila, while testing a new feature.
* Fix multiple problems in WAL replay.Tom Lane2012-11-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the replay functions for WAL record types that modify more than one page failed to ensure that those pages were locked correctly to ensure that concurrent queries could not see inconsistent page states. This is a hangover from coding decisions made long before Hot Standby was added, when it was hardly necessary to acquire buffer locks during WAL replay at all, let alone hold them for carefully-chosen periods. The key problem was that RestoreBkpBlocks was written to hold lock on each page restored from a full-page image for only as long as it took to update that page. This was guaranteed to break any WAL replay function in which there was any update-ordering constraint between pages, because even if the nominal order of the pages is the right one, any mixture of full-page and non-full-page updates in the same record would result in out-of-order updates. Moreover, it wouldn't work for situations where there's a requirement to maintain lock on one page while updating another. Failure to honor an update ordering constraint in this way is thought to be the cause of bug #7648 from Daniel Farina: what seems to have happened there is that a btree page being split was rewritten from a full-page image before the new right sibling page was written, and because lock on the original page was not maintained it was possible for hot standby queries to try to traverse the page's right-link to the not-yet-existing sibling page. To fix, get rid of RestoreBkpBlocks as such, and instead create a new function RestoreBackupBlock that restores just one full-page image at a time. This function can be invoked by WAL replay functions at the points where they would otherwise perform non-full-page updates; in this way, the physical order of page updates remains the same no matter which pages are replaced by full-page images. We can then further adjust the logic in individual replay functions if it is necessary to hold buffer locks for overlapping periods. A side benefit is that we can simplify the handling of concurrency conflict resolution by moving that code into the record-type-specfic functions; there's no more need to contort the code layout to keep conflict resolution in front of the RestoreBkpBlocks call. In connection with that, standardize on zero-based numbering rather than one-based numbering for referencing the full-page images. In HEAD, I removed the macros XLR_BKP_BLOCK_1 through XLR_BKP_BLOCK_4. They are still there in the header files in previous branches, but are no longer used by the code. In addition, fix some other bugs identified in the course of making these changes: spgRedoAddNode could fail to update the parent downlink at all, if the parent tuple is in the same page as either the old or new split tuple and we're not doing a full-page image: it would get fooled by the LSN having been advanced already. This would result in permanent index corruption, not just transient failure of concurrent queries. Also, ginHeapTupleFastInsert's "merge lists" case failed to mark the old tail page as a candidate for a full-page image; in the worst case this could result in torn-page corruption. heap_xlog_freeze() was inconsistent about using a cleanup lock or plain exclusive lock: it did the former in the normal path but the latter for a full-page image. A plain exclusive lock seems sufficient, so change to that. Also, remove gistRedoPageDeleteRecord(), which has been dead code since VACUUM FULL was rewritten. Back-patch to 9.0, where hot standby was introduced. Note however that 9.0 had a significantly different WAL-logging scheme for GIST index updates, and it doesn't appear possible to make that scheme safe for concurrent hot standby queries, because it can leave inconsistent states in the index even between WAL records. Given the lack of complaints from the field, we won't work too hard on fixing that branch.
* Close un-owned SMgrRelations at transaction end.Tom Lane2012-10-17
| | | | | | | | | | | | | | | | | | If an SMgrRelation is not "owned" by a relcache entry, don't allow it to live past transaction end. This design allows the same SMgrRelation to be used for blind writes of multiple blocks during a transaction, but ensures that we don't hold onto such an SMgrRelation indefinitely. Because an SMgrRelation typically corresponds to open file descriptors at the fd.c level, leaving it open when there's no corresponding relcache entry can mean that we prevent the kernel from reclaiming deleted disk space. (While CacheInvalidateSmgr messages usually fix that, there are cases where they're not issued, such as DROP DATABASE. We might want to add some more sinval messaging for that, but I'd be inclined to keep this type of logic anyway, since allowing VFDs to accumulate indefinitely for blind-written relations doesn't seem like a good idea.) This code replaces a previous attempt towards the same goal that proved to be unreliable. Back-patch to 9.1 where the previous patch was added.
* Properly set relpersistence for fake relcache entries.Robert Haas2012-09-14
| | | | | | | This can result in buffers failing to be properly flushed at checkpoint time, leading to data loss. Report, diagnosis, and patch by Jeff Davis.
* Fix inappropriate error messages for Hot Standby misconfiguration errors.Tom Lane2012-09-05
| | | | | | | | Give the correct name of the GUC parameter being complained of. Also, emit a more suitable SQLSTATE (INVALID_PARAMETER_VALUE, not the default INTERNAL_ERROR). Gurjeet Singh, errcode adjustment by me
* Back-patch recent fixes for gistchoose and gistRelocateBuildBuffersOnSplit.Tom Lane2012-08-30
| | | | | | | | | | | | | | | | This back-ports commits c8ba697a4bdb934f0c51424c654e8db6133ea255 and e5db11c5582b469c04a11f217a0f32c827da5dd7, which fix one definite and one speculative bug in gistchoose, and make the code a lot more intelligible as well. In 9.2 only, this also affects the largely-copied-and-pasted logic in gistRelocateBuildBuffersOnSplit. The impact of the bugs was that the functions might make poor decisions as to which index tree branch to push a new entry down into, resulting in GiST index bloat and poor performance. The fixes rectify these decisions for future insertions, but a REINDEX would be needed to clean up any existing index bloat. Alexander Korotkov, Robert Haas, Tom Lane
* fsync backup_label after pg_start_backup()Simon Riggs2012-08-07
| | | | Dave Kerr, backpatched by Simon Riggs
* Initialize shared memory copy of ckptXidEpoch correctly when not in recovery.Heikki Linnakangas2012-06-29
| | | | | | | This bug was introduced by commit 20d98ab6e4110087d1816cd105a40fcc8ce0a307, so backpatch this to 9.0-9.2 like that one. This fixes bug #6710, reported by Tarvi Pillessaar
* Wake WALSender to reduce data loss at failover for async commit.Simon Riggs2012-06-07
| | | | | | | | | WALSender now woken up after each background flush by WALwriter, avoiding multi-second replication delay for an all-async commit workload. Replication delay reduced from 7s with default settings to 200ms, allowing significantly reduced data loss at failover. Andres Freund and Simon Riggs
* Avoid early reuse of btree pages, causing incorrect query results.Simon Riggs2012-06-01
| | | | | | | | | | | | | When we allowed read-only transactions to skip assigning XIDs we introduced the possibility that a fully deleted btree page could be reused. This broke the index link sequence which could then lead to indexscans silently returning fewer rows than would have been correct. The actual incidence of silent errors from this is thought to be very low because of the exact workload required and locking pre-conditions. Fix is to remove pages only if index page opaque->btpo.xact precedes RecentGlobalXmin. Noah Misch, reviewed by Simon Riggs
* Revert back-branch changes in behavior of age(xid).Tom Lane2012-05-31
| | | | | | | | Per discussion, it does not seem like a good idea to change the behavior of age(xid) in a minor release, even though the old definition causes the function to fail on hot standby slaves. Therefore, revert commit 5829387381d2e4edf84652bb5a712f6185860670 and follow-on commits in the back branches only.
* Teach AbortOutOfAnyTransaction to clean up partially-started transactions.Tom Lane2012-05-28
| | | | | | | | | | | | AbortOutOfAnyTransaction failed to do anything if the state it saw on entry corresponded to failing partway through StartTransaction. I fixed AbortCurrentTransaction to cope with that case way back in commit 60b2444cc3ba037630c9b940c3c9ef01b954b87b, but evidently overlooked that AbortOutOfAnyTransaction should do likewise. Back-patch to all supported branches. It's not clear that this omission has any more-than-cosmetic consequences, but it's also not clear that it doesn't, so back-patching seems the least risky choice.
* Prevent synchronized scanning when systable_beginscan chooses a heapscan.Tom Lane2012-05-26
| | | | | | | | | | | | | | | The only interesting-for-performance case wherein we force heapscan here is when we're rebuilding the relcache init file, and the only such case that is likely to be examining a catalog big enough to be syncscanned is RelationBuildTupleDesc. But the early-exit optimization in that code gets broken if we start the scan at a random place within the catalog, so that allowing syncscan is actually a big deoptimization if pg_attribute is large (at least for the normal case where the rows for core system catalogs have never been changed since initdb). Hence, prevent syncscan here. Per my testing pursuant to complaints from Jeff Frost and Greg Sabino Mullane, though neither of them seem to have actually hit this specific problem. Back-patch to 8.3, where syncscan was introduced.
* Ensure that seqscans check for interrupts at least once per page.Tom Lane2012-05-22
| | | | | | | | | | | | | If a seqscan encounters many consecutive pages containing only dead tuples, it can remain in the loop in heapgettup for a long time, and there was no CHECK_FOR_INTERRUPTS anywhere in that loop. This meant there were real-world situations where a query would be effectively uncancelable for long stretches. Add a check placed to occur once per page, which should be enough to provide reasonable response time without adding any measurable overhead. Report and patch by Merlin Moncure (though I tweaked it a bit). Back-patch to all supported branches.
* Ensure backwards compatibility for GetStableLatestTransactionId()Simon Riggs2012-05-12
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* Ensure age() returns a stable value rather than the latest valueSimon Riggs2012-05-11
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* On GiST page split, release the locks on child pages before recursing up.Heikki Linnakangas2012-05-11
| | | | | | | | | | | | | | | | | | When inserting the downlinks for a split gist page, we used hold the locks on the child pages until the insertion into the parent - and recursively its parent if it had to be split too - were all completed. Change that so that the locks on child pages are released after the insertion in the immediate parent is done, before recursing further up the tree. This reduces the number of lwlocks that are held simultaneously. Holding many locks is bad for concurrency, and in extreme cases you can even hit the limit of 100 simultaneously held lwlocks in a backend. If you're really unlucky, you can hit the limit while in a critical section, which brings down the whole system. This fixes bug #6629 reported by Tom Forbes. Backpatch to 9.1. The page splitting code was rewritten in 9.1, and the old code did not have this problem.
* Don't wait for the commit record to be replicated if we wrote no WAL.Heikki Linnakangas2012-04-17
| | | | | | | | When using synchronous replication, we waited for the commit record to be replicated, but if we our transaction didn't write any other WAL records, that's not required because we don't even flush the WAL locally to disk in that case. This lead to long waits when committing a transaction that only modified a temporary table. Bug spotted by Thom Brown.
* Fix misleading output from gin_desc().Tom Lane2012-04-06
| | | | | | | | | | | XLOG_GIN_UPDATE_META_PAGE and XLOG_GIN_DELETE_LISTPAGE records were printed with a list link field labeled as "blkno", which was confusing, especially when the link was empty (InvalidBlockNumber). Print the metapage block number instead, since that's what's actually being updated. We could include the link values too as a separate field, but not clear it's worth the trouble. Back-patch to 8.4 where the dubious code was added.
* Correct epoch of txid_current() when executed on a Hot Standby server.Simon Riggs2012-03-29
| | | | | | | | | Initialise ckptXidEpoch from starting checkpoint and maintain the correct value as we roll forwards. This allows GetNextXidAndEpoch() to return the correct epoch when executed during recovery. Backpatch to 9.0 when the problem is first observable by a user. Bug report from Daniel Farina
* Fix some more bugs in GIN's WAL replay logic.Tom Lane2012-02-26
| | | | | | | | | | | | | | | | | | In commit 4016bdef8aded77b4903c457050622a5a1815c16 I fixed a bunch of ginxlog.c bugs having to do with not handling XLogReadBuffer failures correctly. However, in ginRedoUpdateMetapage and ginRedoDeleteListPages, I unaccountably thought that failure to read the metapage would be impossible and just put in an elog(PANIC) call. This is of course wrong: failure is exactly what will happen if the index got dropped (or rebuilt) between creation of the WAL record and the crash we're trying to recover from. I believe this explains Nicholas Wilson's recent report of these errors getting reached. Also, fix memory leak in forgetIncompleteSplit. This wasn't of much concern when the code was written, but in a long-running standby server page split records could be expected to accumulate indefinitely. Back-patch to 8.4 --- before that, GIN didn't have a metapage.
* Correctly initialise shared recoveryLastRecPtr in recovery.Simon Riggs2012-02-22
| | | | | | | | Previously we used ReadRecPtr rather than EndRecPtr, which was not a serious error but caused pg_stat_replication to report incorrect replay_location until at least one WAL record is replayed. Fujii Masao
* Don't clear btpo_cycleid during _bt_vacuum_one_page.Tom Lane2012-02-21
| | | | | | | | | | | | | | When "vacuuming" a single btree page by removing LP_DEAD tuples, we are not actually within a vacuum operation, but rather in an ordinary insertion process that could well be running concurrently with a vacuum. So clearing the cycleid is incorrect, and could cause the concurrent vacuum to miss removing tuples that it needs to remove. This is a longstanding bug introduced by commit e6284649b9e30372b3990107a082bc7520325676 of 2006-07-25. I believe it explains Maxim Boguk's recent report of index corruption, and probably some other previously unexplained reports. In 9.0 and up this is a one-line fix; before that we need to introduce a flag to tell _bt_delitems what to do.
* Throw error sooner for unlogged GiST indexes.Tom Lane2012-02-08
| | | | | | Throwing an error only after we've built the main index fork is pretty unfriendly when the table already contains data. Per gripe from Jay Levitt.
* Avoid problems with OID wraparound during WAL replay.Tom Lane2012-02-06
| | | | | | | | | | | | | | | | | | | | | | | | Fix a longstanding thinko in replay of NEXTOID and checkpoint records: we tried to advance nextOid only if it was behind the value in the WAL record, but the comparison would draw the wrong conclusion if OID wraparound had occurred since the previous value. Better to just unconditionally assign the new value, since OID assignment shouldn't be happening during replay anyway. The consequences of a failure to update nextOid would be pretty minimal, since we have long had the code set up to obtain another OID and try again if the generated value is already in use. But in the worst case there could be significant performance glitches while such loops iterate through many already-used OIDs before finding a free one. The odds of a wraparound happening during WAL replay would be small in a crash-recovery scenario, and the length of any ensuing OID-assignment stall quite limited anyway. But neither of these statements hold true for a replication slave that follows a WAL stream for a long period; its behavior upon going live could be almost unboundedly bad. Hence it seems worth back-patching this fix into all supported branches. Already fixed in HEAD in commit c6d76d7c82ebebb7210029f7382c0ebe2c558bca.
* Fix transient clobbering of shared buffers during WAL replay.Tom Lane2012-02-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | RestoreBkpBlocks was in the habit of zeroing and refilling the target buffer; which was perfectly safe when the code was written, but is unsafe during Hot Standby operation. The reason is that we have coding rules that allow backends to continue accessing a tuple in a heap relation while holding only a pin on its buffer. Such a backend could see transiently zeroed data, if WAL replay had occasion to change other data on the page. This has been shown to be the cause of bug #6425 from Duncan Rance (who deserves kudos for developing a sufficiently-reproducible test case) as well as Bridget Frey's re-report of bug #6200. It most likely explains the original report as well, though we don't yet have confirmation of that. To fix, change the code so that only bytes that are supposed to change will change, even transiently. This actually saves cycles in RestoreBkpBlocks, since it's not writing the same bytes twice. Also fix seq_redo, which has the same disease, though it has to work a bit harder to meet the requirement. So far as I can tell, no other WAL replay routines have this type of bug. In particular, the index-related replay routines, which would certainly be broken if they had to meet the same standard, are not at risk because we do not have coding rules that allow access to an index page when not holding a buffer lock on it. Back-patch to 9.0 where Hot Standby was added.
* Fix CLUSTER/VACUUM FULL for toast values owned by recently-updated rows.Tom Lane2012-01-12
| | | | | | | | | | | | | | | | | | | | | | | | | | In commit 7b0d0e9356963d5c3e4d329a917f5fbb82a2ef05, I made CLUSTER and VACUUM FULL try to preserve toast value OIDs from the original toast table to the new one. However, if we have to copy both live and recently-dead versions of a row that has a toasted column, those versions may well reference the same toast value with the same OID. The patch then led to duplicate-key failures as we tried to insert the toast value twice with the same OID. (The previous behavior was not very desirable either, since it would have silently inserted the same value twice with different OIDs. That wastes space, but what's worse is that the toast values inserted for already-dead heap rows would not be reclaimed by subsequent ordinary VACUUMs, since they go into the new toast table marked live not deleted.) To fix, check if the copied OID already exists in the new toast table, and if so, assume that it stores the desired value. This is reasonably safe since the only case where we will copy an OID from a previous toast pointer is when toast_insert_or_update was given that toast pointer and so we just pulled the data from the old table; if we got two different values that way then we have big problems anyway. We do have to assume that no other backend is inserting items into the new toast table concurrently, but that's surely safe for CLUSTER and VACUUM FULL. Per bug #6393 from Maxim Boguk. Back-patch to 9.0, same as the previous patch.
* Avoid crashing when we have problems unlinking files post-commit.Tom Lane2011-12-20
| | | | | | | | | | | | | | | | | | smgrdounlink takes care to not throw an ERROR if it fails to unlink something, but that caution was rendered useless by commit 3396000684b41e7e9467d1abc67152b39e697035, which put an smgrexists call in front of it; smgrexists *does* throw error if anything looks funny, such as getting a permissions error from trying to open the file. If that happens post-commit, you get a PANIC, and what's worse the same logic appears in the WAL replay code, so the database even fails to restart. Restore the intended behavior by removing the smgrexists call --- it isn't accomplishing anything that we can't do better by adjusting mdunlink's ideas of whether it ought to warn about ENOENT or not. Per report from Joseph Shraibman of unrecoverable crash after trying to drop a table whose FSM fork had somehow gotten chmod'd to 000 permissions. Backpatch to 8.4, where the bogus coding was introduced.
* Don't set reachedMinRecoveryPoint during crash recovery. In crash recovery,Heikki Linnakangas2011-12-09
| | | | | | | | | | | | | | | we don't reach consistency before replaying all of the WAL. Rename the variable to reachedConsistency, to make its intention clearer. In master, that was an active bug because of the recent patch to immediately PANIC if a reference to a missing page is found in WAL after reaching consistency, as Tom Lane's test case demonstrated. In 9.1 and 9.0, the only consequence was a misleading "consistent recovery state reached at %X/%X" message in the log at the beginning of crash recovery (the database is not consistent at that point yet). In 8.4, the log message was not printed in crash recovery, even though there was a similar reachedMinRecoveryPoint local variable that was also set early. So, backpatch to 9.1 and 9.0.
* Fix erroneous replay of GIN_UPDATE_META_PAGE WAL records.Tom Lane2011-11-25
| | | | | | | | | | | | | A simple thinko in ginRedoUpdateMetapage, namely failing to increment a loop counter, led to inserting records into the last pending-list page in the wrong order (the opposite of that intended). So far as I can tell, this would not upset the code that eventually flushes pending items into the main part of the GIN index. But it did break the code that searched the pending list for matches, resulting in transient failure to find matching entries during index lookups, as illustrated in bug #6307 from Maksym Boguk. Back-patch to 8.4 where the incorrect code was introduced.
* Don't assume that a tuple's header size is unchanged during toasting.Tom Lane2011-11-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This assumption can be wrong when the toaster is passed a raw on-disk tuple, because the tuple might pre-date an ALTER TABLE ADD COLUMN operation that added columns without rewriting the table. In such a case the tuple's natts value is smaller than what we expect from the tuple descriptor, and so its t_hoff value could be smaller too. In fact, the tuple might not have a null bitmap at all, and yet our current opinion of it is that it contains some trailing nulls. In such a situation, toast_insert_or_update did the wrong thing, because to save a few lines of code it would use the old t_hoff value as the offset where heap_fill_tuple should start filling data. This did not leave enough room for the new nulls bitmap, with the result that the first few bytes of data could be overwritten with null flag bits, as in a recent report from Hubert Depesz Lubaczewski. The particular case reported requires ALTER TABLE ADD COLUMN followed by CREATE TABLE AS SELECT * FROM ... or INSERT ... SELECT * FROM ..., and further requires that there be some out-of-line toasted fields in one of the tuples to be copied; else we'll not reach the troublesome code. The problem can only manifest in this form in 8.4 and later, because before commit a77eaa6a95009a3441e0d475d1980259d45da072, CREATE TABLE AS or INSERT/SELECT wouldn't result in raw disk tuples getting passed directly to heap_insert --- there would always have been at least a junkfilter in between, and that would reconstitute the tuple header with an up-to-date t_natts and hence t_hoff. But I'm backpatching the tuptoaster change all the way anyway, because I'm not convinced there are no older code paths that present a similar risk.
* Revert "Stop btree indexscans upon reaching nulls in either direction."Tom Lane2011-11-02
| | | | | | | This reverts commit 048fffed55ff1d6d346130e4a6b7be434e81e82c. As pointed out by Naoya Anzai, we need to do more work to make that idea handle end-of-index cases, and it is looking like too much risk for a back-patch. So bug #6278 is only going to be fixed in HEAD.
* Derive oldestActiveXid at correct time for Hot Standby.Simon Riggs2011-11-02
| | | | | | | | | There was a timing window between when oldestActiveXid was derived and when it should have been derived that only shows itself under heavy load. Move code around to ensure correct timing of derivation. No change to StartupSUBTRANS() code, which is where this failed. Bug report by Chris Redekop
* Fix timing of Startup CLOG and MultiXact during Hot StandbySimon Riggs2011-11-02
| | | | Patch by me, bug report by Chris Redekop, analysis by Florian Pflug
* Fix race condition with toast table access from a stale syscache entry.Tom Lane2011-11-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a tuple in a syscache contains an out-of-line toasted field, and we try to fetch that field shortly after some other transaction has committed an update or deletion of the tuple, there is a race condition: vacuum could come along and remove the toast tuples before we can fetch them. This leads to transient failures like "missing chunk number 0 for toast value NNNNN in pg_toast_2619", as seen in recent reports from Andrew Hammond and Tim Uckun. The design idea of syscache is that access to stale syscache entries should be prevented by relation-level locks, but that fails for at least two cases where toasted fields are possible: ANALYZE updates pg_statistic rows without locking out sessions that might want to plan queries on the same table, and CREATE OR REPLACE FUNCTION updates pg_proc rows without any meaningful lock at all. The least risky fix seems to be an idea that Heikki suggested when we were dealing with a related problem back in August: forcibly detoast any out-of-line fields before putting a tuple into syscache in the first place. This avoids the problem because at the time we fetch the parent tuple from the catalog, we should be holding an MVCC snapshot that will prevent removal of the toast tuples, even if the parent tuple is outdated immediately after we fetch it. (Note: I'm not convinced that this statement holds true at every instant where we could be fetching a syscache entry at all, but it does appear to hold true at the times where we could fetch an entry that could have a toasted field. We will need to be a bit wary of adding toast tables to low-level catalogs that don't have them already.) An additional benefit is that subsequent uses of the syscache entry should be faster, since they won't have to detoast the field. Back-patch to all supported versions. The problem is significantly harder to reproduce in pre-9.0 releases, because of their willingness to flush every entry in a syscache whenever the underlying catalog is vacuumed (cf CatalogCacheFlushRelation); but there is still a window for trouble.
* Stop btree indexscans upon reaching nulls in either direction.Tom Lane2011-10-31
| | | | | | | | | | | The existing scan-direction-sensitive tests were overly complex, and failed to stop the scan in cases where it's perfectly legitimate to do so. Per bug #6278 from Maksym Boguk. Back-patch to 8.3, which is as far back as the patch applies easily. Doesn't seem worth sweating over a relatively minor performance issue in 8.2 at this late date. (But note that this was a performance regression from 8.1 and before, so 8.2 is being left as an outlier.)
* Avoid unnecessary page-level SSI lock check in heap_insert().Tom Lane2011-09-16
| | | | | | | | | | As observed by Heikki, we need not conflict on heap page locks during an insert; heap page locks are only aggregated tuple locks, they don't imply locking "gaps" as index page locks do. So we can avoid some unnecessary conflicts, and also do the SSI check while not holding exclusive lock on the target buffer. Kevin Grittner, reviewed by Jeff Davis. Back-patch to 9.1.
* gistendscan() forgot to free so->giststate.Tom Lane2011-09-16
| | | | | | | | | | This oversight led to a massive memory leak --- upwards of 10KB per tuple --- during creation-time verification of an exclusion constraint based on a GIST index. In most other scenarios it'd just be a leak of 10KB that would be recovered at end of query, so not too significant; though perhaps the leak would be noticeable in a situation where a GIST index was being used in a nestloop inner indexscan. In any case, it's a real leak of long standing, so patch all supported branches. Per report from Harald Fuchs.
* Adjust translator comment format to xgettext expectationsAlvaro Herrera2011-09-05
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* Mark some untranslatable messages with errmsg_internalAlvaro Herrera2011-09-05
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* If backup-end record is not seen, and we reach end of recovery from aHeikki Linnakangas2011-08-17
| | | | | | | | | | | | | | | | | | | streamed backup, throw an error and refuse to start up. The restore has not finished correctly in that case and the data directory is possibly corrupt. We already errored out in case of archive recovery, but could not during crash recovery because we couldn't distinguish between the case that pg_start_backup() was called and the database then crashed (must not error, data is OK), and the case that we're restoring from a backup and not all the needed WAL was replayed (data can be corrupt). To distinguish those cases, add a line to backup_label to indicate whether the backup was taken with pg_start/stop_backup(), or by streaming (ie. pg_basebackup). This is a different implementation than what I committed to 9.2 a week ago. That implementation was not back-patchable because it required re-initdb. Fujii Masao
* Preserve toast value OIDs in toast-swap-by-content for CLUSTER/VACUUM FULL.Tom Lane2011-08-16
| | | | | | | | | | | | | | | | | This works around the problem that a catalog cache entry might contain a toast pointer that we try to dereference just as a VACUUM FULL completes on that catalog. We will see the sinval message on the cache entry when we acquire lock on the toast table, but by that point we've already told tuptoaster.c "here's the pointer to fetch", so it's difficult from a code structural standpoint to update the pointer before we use it. Much less painful to ensure that toast pointers are not invalidated in the first place. We have to add a bit of code to deal with the case that a value that previously wasn't toasted becomes so; but that should be a seldom-exercised corner case, so the inefficiency shouldn't be significant. Back-patch to 9.0. In prior versions, we didn't allow CLUSTER on system catalogs, and VACUUM FULL didn't result in reassignment of toast OIDs, so there was no problem.
* Fix race condition in relcache init file invalidation.Tom Lane2011-08-16
| | | | | | | | | | | | | | | | The previous code tried to synchronize by unlinking the init file twice, but that doesn't actually work: it leaves a window wherein a third process could read the already-stale init file but miss the SI messages that would tell it the data is stale. The result would be bizarre failures in catalog accesses, typically "could not read block 0 in file ..." later during startup. Instead, hold RelCacheInitLock across both the unlink and the sending of the SI messages. This is more straightforward, and might even be a bit faster since only one unlink call is needed. This has been wrong since it was put in (in 2002!), so back-patch to all supported releases.
* Back-patch assorted latch-related fixes.Tom Lane2011-08-10
| | | | | | | | | | Fix a whole bunch of signal handlers that had been hacked to do things that might change errno, without adding the necessary save/restore logic for errno. Also make some minor fixes in unix_latch.c, and clean up bizarre and unsafe scheme for disowning the process's latch. While at it, rename the PGPROC latch field to procLatch for consistency with 9.2. Issues noted while reviewing a patch by Peter Geoghegan.
* Measure WaitLatch's timeout parameter in milliseconds, not microseconds.Tom Lane2011-08-09
| | | | | | | | | | | | The original definition had the problem that timeouts exceeding about 2100 seconds couldn't be specified on 32-bit machines. Milliseconds seem like sufficient resolution, and finer grain than that would be fantasy anyway on many platforms. Back-patch to 9.1 so that this aspect of the latch API won't change between 9.1 and later releases. Peter Geoghegan
* Fix two ancient bugs in GiST code to re-find a parent after page split:Heikki Linnakangas2011-07-15
| | | | | | | | | | | | | | | | | | | | | | | | First, when following a right-link, we incorrectly marked the current page as the parent of the right sibling. In reality, the parent of the right page is the same as the parent of the current page (or some page to the right of it, gistFindCorrectParent() will sort that out). Secondly, when we follow a right-link, we must prepend, not append, the right page to our list of pages to visit. That's because we assume that once we hit a leaf page in the list, all the rest are leaf pages too, and give up. To hit these bugs, you need concurrent actions and several unlucky accidents. Another backend must split the root page, while you're in process of splitting a lower-level page. Furthermore, while you scan the internal nodes to re-find the parent, another backend needs to again split some more internal pages. Even then, the bugs don't necessarily manifest as user-visible errors or index corruption. While we're at it, make the error reporting a bit better if gistFindPath() fails to re-find the parent. It used to be an assertion, but an elog() seems more appropriate. Backpatch to all supported branches.
* Unify spelling of "canceled", "canceling", "cancellation"Peter Eisentraut2011-07-02
| | | | | We had previously (af26857a2775e7ceb0916155e931008c2116632f) established the U.S. spellings as standard.
* Restore correct btree preprocessing of "indexedcol IS NULL" conditions.Tom Lane2011-06-29
| | | | | | | | | | | | Such a condition is unsatisfiable in combination with any other type of btree-indexable condition (since we assume btree operators are always strict). 8.3 and 8.4 had an explicit test for this, which I removed in commit 29c4ad98293e3c5cb3fcdd413a3f4904efff8762, mistakenly thinking that the case would be subsumed by the more general handling of IS (NOT) NULL added in that patch. Put it back, and improve the comments about it, and add a regression test case. Per bug #6079 from Renat Nasyrov, and analysis by Dean Rasheed.
* Move the PredicateLockRelation() call from nodeSeqscan.c to heapam.c. It'sHeikki Linnakangas2011-06-29
| | | | | | | | | | | | | | | | | | | | more consistent that way, since all the other PredicateLock* calls are made in various heapam.c and index AM functions. The call in nodeSeqscan.c was unnecessarily aggressive anyway, there's no need to try to lock the relation every time a tuple is fetched, it's enough to do it once. This has the user-visible effect that if a seq scan is initialized in the executor, but never executed, we now acquire the predicate lock on the heap relation anyway. We could avoid that by taking the lock on the first heap_getnext() call instead, but it doesn't seem worth the trouble given that it feels more natural to do it in heap_beginscan(). Also, remove the retail PredicateLockTuple() calls from heap_getnext(). In a seqscan, started with heap_begin(), we're holding a whole-relation predicate lock on the heap so there's no need to lock the tuples individually. Kevin Grittner and me