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* Fix ancient docs/comments thinko: XID comparison is mod 2^32, not 2^31.Tom Lane2013-12-12
| | | | Pointed out by Gianni Ciolli.
* Fix full-page writes of internal GIN pages.Heikki Linnakangas2013-12-03
| | | | | | | | | | | | | | | Insertion to a non-leaf GIN page didn't make a full-page image of the page, which is wrong. The code used to do it correctly, but was changed (commit 853d1c3103fa961ae6219f0281885b345593d101) because the redo-routine didn't track incomplete splits correctly when the page was restored from a full page image. Of course, that was not right way to fix it, the redo routine should've been fixed instead. The redo-routine was surreptitiously fixed in 2010 (commit 4016bdef8aded77b4903c457050622a5a1815c16), so all we need to do now is revert the code that creates the record to its original form. This doesn't change the format of the WAL record. Backpatch to all supported versions.
* Fix incomplete backpatch of pg_multixact truncation changes to <= 9.2Alvaro Herrera2013-12-02
| | | | | | | | | | | | | | The backpatch of a95335b544d9c8377e9dc7a399d8e9a155895f82 to 9.2, 9.1 and 9.0 was incomplete, missing changes to xlog.c, primarily the call to TrimMultiXact(). Testing presumably didn't show a problem without these changes because TrimMultiXact() performs defense-in-depth work, which is not strictly necessary. It also missed moving StartupMultiXact() which would have been problematic if a restartpoing happened in exactly the wrong moment, causing a transient error. Andres Freund
* Truncate pg_multixact/'s contents during crash recoveryAlvaro Herrera2013-11-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 9dc842f08 of 8.2 era prevented MultiXact truncation during crash recovery, because there was no guarantee that enough state had been setup, and because it wasn't deemed to be a good idea to remove data during crash recovery anyway. Since then, due to Hot-Standby, streaming replication and PITR, the amount of time a cluster can spend doing crash recovery has increased significantly, to the point that a cluster may even never come out of it. This has made not truncating the content of pg_multixact/ not defensible anymore. To fix, take care to setup enough state for multixact truncation before crash recovery starts (easy since checkpoints contain the required information), and move the current end-of-recovery actions to a new TrimMultiXact() function, analogous to TrimCLOG(). At some later point, this should probably done similarly to the way clog.c is doing it, which is to just WAL log truncations, but we can't do that for the back branches. Back-patch to 9.0. 8.4 also has the problem, but since there's no hot standby there, it's much less pressing. In 9.2 and earlier, this patch is simpler than in newer branches, because multixact access during recovery isn't required. Add appropriate checks to make sure that's not happening. Andres Freund
* Fix Hot-Standby initialization of clog and subtrans.Heikki Linnakangas2013-11-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These bugs can cause data loss on standbys started with hot_standby=on at the moment they start to accept read only queries, by marking committed transactions as uncommited. The likelihood of such corruptions is small unless the primary has a high transaction rate. 5a031a5556ff83b8a9646892715d7fef415b83c3 fixed bugs in HS's startup logic by maintaining less state until at least STANDBY_SNAPSHOT_PENDING state was reached, missing the fact that both clog and subtrans are written to before that. This only failed to fail in common cases because the usage of ExtendCLOG in procarray.c was superflous since clog extensions are actually WAL logged. f44eedc3f0f347a856eea8590730769125964597/I then tried to fix the missing extensions of pg_subtrans due to the former commit's changes - which are not WAL logged - by performing the extensions when switching to a state > STANDBY_INITIALIZED and not performing xid assignments before that - again missing the fact that ExtendCLOG is unneccessary - but screwed up twice: Once because latestObservedXid wasn't updated anymore in that state due to the earlier commit and once by having an off-by-one error in the loop performing extensions. This means that whenever a CLOG_XACTS_PER_PAGE (32768 with default settings) boundary was crossed between the start of the checkpoint recovery started from and the first xl_running_xact record old transactions commit bits in pg_clog could be overwritten if they started and committed in that window. Fix this mess by not performing ExtendCLOG() in HS at all anymore since it's unneeded and evidently dangerous and by performing subtrans extensions even before reaching STANDBY_SNAPSHOT_PENDING. Analysis and patch by Andres Freund. Reported by Christophe Pettus. Backpatch down to 9.0, like the previous commit that caused this.
* Fix race condition in GIN posting tree page deletion.Heikki Linnakangas2013-11-08
| | | | | | | | | | | | | | | | | | If a page is deleted, and reused for something else, just as a search is following a rightlink to it from its left sibling, the search would continue scanning whatever the new contents of the page are. That could lead to incorrect query results, or even something more curious if the page is reused for a different kind of a page. To fix, modify the search algorithm to lock the next page before releasing the previous one, and refrain from deleting pages from the leftmost branch of the tree. Add a new Concurrency section to the README, explaining why this works. There is a lot more one could say about concurrency in GIN, but that's for another patch. Backpatch to all supported versions.
* Prevent using strncpy with src == dest in TupleDescInitEntry.Tom Lane2013-10-28
| | | | | | | | | | | | | | | | | The C and POSIX standards state that strncpy's behavior is undefined when source and destination areas overlap. While it remains dubious whether any implementations really misbehave when the pointers are exactly equal, some platforms are now starting to force the issue by complaining when an undefined call occurs. (In particular OS X 10.9 has been seen to dump core here, though the exact set of circumstances needed to trigger that remain elusive. Similar behavior can be expected to be optional on Linux and other platforms in the near future.) So tweak the code to explicitly do nothing when nothing need be done. Back-patch to all active branches. In HEAD, this also lets us get rid of an exception in valgrind.supp. Per discussion of a report from Matthias Schmitt.
* Oops. Unbreak the 9.1 build.Heikki Linnakangas2013-10-08
| | | | | I forgot to "git add" latest changes after backpatching the changes for previous commit.
* Fix bugs in SSI tuple locking.Heikki Linnakangas2013-10-08
| | | | | | | | | | | | | 1. In heap_hot_search_buffer(), the PredicateLockTuple() call is passed wrong offset number. heapTuple->t_self is set to the tid of the first tuple in the chain that's visited, not the one actually being read. 2. CheckForSerializableConflictIn() uses the tuple's t_ctid field instead of t_self to check for exiting predicate locks on the tuple. If the tuple was updated, but the updater rolled back, t_ctid points to the aborted dead tuple. Reported by Hannu Krosing. Backpatch to 9.1.
* Fix pgindent comment breakageAlvaro Herrera2013-09-24
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* Ensure no xid gaps during Hot Standby startupSimon Riggs2013-06-23
| | | | | | | | | In some cases with higher numbers of subtransactions it was possible for us to incorrectly initialize subtrans leading to complaints of missing pages. Bug report by Sergey Konoplev Analysis and fix by Andres Freund
* Fix typo in comment.Heikki Linnakangas2013-06-06
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* Fix handling of OID wraparound while in standalone mode.Tom Lane2013-05-13
| | | | | | | | | | | If OID wraparound should occur while in standalone mode (unlikely but possible), we want to advance the counter to FirstNormalObjectId not FirstBootstrapObjectId. Otherwise, user objects might be created with OIDs in the system-reserved range. That isn't immediately harmful but it poses a risk of conflicts during future pg_upgrade operations. Noted by Andres Freund. Back-patch to all supported branches, since all of them are supported sources for pg_upgrade operations.
* Fix thinko in comment.Heikki Linnakangas2013-05-02
| | | | | | | WAL segment means a 16 MB physical WAL file; this comment meant a logical 4 GB log file. Amit Langote. Apply to backbranches only, as the comment is gone in master.
* Install recycled WAL segments with current timeline ID during recovery.Heikki Linnakangas2013-04-30
| | | | | | | | | | | | | | This is a follow-up to the earlier fix, which changed the recycling logic to recycle WAL segments under the current recovery target timeline. That turns out to be a bad idea, because installing a recycled segment with a TLI higher than what we're recovering at the moment means that the recovery logic will find the recycled WAL segment and try to replay it. It will fail, but but the mere presence of such a WAL segment will mask any other, real, file with the same log/seg, but smaller TLI. Per report from Mitsumasa Kondo. Apply to 9.1 and 9.2, like the previous fix. Master was already doing this differently; this patch makes 9.1 and 9.2 to do the same thing as master.
* Make REPLICATION privilege checks test current user not authenticated user.Tom Lane2013-04-01
| | | | | | | | | | | The pg_start_backup() and pg_stop_backup() functions checked the privileges of the initially-authenticated user rather than the current user, which is wrong. For example, a user-defined index function could successfully call these functions when executed by ANALYZE within autovacuum. This could allow an attacker with valid but low-privilege database access to interfere with creation of routine backups. Reported and fixed by Noah Misch. Security: CVE-2013-1901
* Fix buffer pin leak in heap update redo routine.Heikki Linnakangas2013-03-27
| | | | | | | | | | | | | | In a heap update, if the old and new tuple were on different pages, and the new page no longer existed (because it was subsequently truncated away by vacuum), heap_xlog_update forgot to release the pin on the old buffer. This bug was introduced by the "Fix multiple problems in WAL replay" patch, commit 3bbf668de9f1bc172371681e80a4e769b6d014c8 (on master branch). With full_page_writes=off, this triggered an "incorrect local pin count" error later in replay, if the old page was vacuumed. This fixes bug #7969, reported by Yunong Xiao. Backpatch to 9.0, like the commit that introduced this bug.
* Further cleanup of gistsplit.c.Tom Lane2013-02-10
| | | | | | | | | | | | | | | | | | | | After further reflection I was unconvinced that the existing coding is guaranteed to return valid union datums in every code path for multi-column indexes. Fix that by forcing a gistunionsubkey() call at the end of the recursion. Having done that, we can remove some clearly-redundant calls elsewhere. This should be a little faster for multi-column indexes (since the previous coding would uselessly do such a call for each column while unwinding the recursion), as well as much harder to break. Also, simplify the handling of cases where one side or the other of a primary split contains only don't-care tuples. The previous coding used a very ugly hack in removeDontCares() that essentially forced one random tuple to be treated as non-don't-care, providing a random initial choice of seed datum for the secondary split. It seems unlikely that that method will give better-than-random splits. Instead, treat such a split as degenerate and just let the next column determine the split, the same way that we handle fully degenerate cases where the two sides produce identical union datums.
* Remove useless picksplit-doesn't-support-secondary-split log spam.Tom Lane2013-02-10
| | | | | | | | | | | | | | This LOG message was put in over five years ago with the evident expectation that we'd make all GiST opclasses support secondary split directly. However, no such thing ever happened, and indeed the number of opclasses supporting it decreased to zero in 9.2. The reason is that improving on the default implementation isn't that easy --- the opclass-specific code that did exist, before 9.2, doesn't appear to have been any improvement over the default. Hence, remove the message altogether. There's certainly no point in nagging users about this in released branches, but I doubt that we'll ever implement complete opclass-specific support anyway.
* Document and clean up gistsplit.c.Tom Lane2013-02-10
| | | | | | | | | | Improve comments, rename some variables and functions, slightly simplify a couple of APIs, in an attempt to make this code readable by people other than its original author. Even though this is essentially just cosmetic, back-patch to all active branches, because otherwise it's going to make back-patching future fixes in this file very painful.
* Fix gist_box_same and gist_point_consistent to handle fuzziness correctly.Tom Lane2013-02-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | While there's considerable doubt that we want fuzzy behavior in the geometric operators at all (let alone as currently implemented), nobody is stepping forward to redesign that stuff. In the meantime it behooves us to make sure that index searches agree with the behavior of the underlying operators. This patch fixes two problems in this area. First, gist_box_same was using fuzzy equality, but it really needs to use exact equality to prevent not-quite-identical upper index keys from being treated as identical, which for example would prevent an existing upper key from being extended by an amount less than epsilon. This would result in inconsistent indexes. (The next release notes will need to recommend that users reindex GiST indexes on boxes, polygons, circles, and points, since all four opclasses use gist_box_same.) Second, gist_point_consistent used exact comparisons for upper-page comparisons in ~= searches, when it needs to use fuzzy comparisons to ensure it finds all matches; and it used fuzzy comparisons for point <@ box searches, when it needs to use exact comparisons because that's what the <@ operator (rather inconsistently) does. The added regression test cases illustrate all three misbehaviors. Back-patch to all active branches. (8.4 did not have GiST point_ops, but it still seems prudent to apply the gist_box_same patch to it.) Alexander Korotkov, reviewed by Noah Misch
* Repair bugs in GiST page splitting code for multi-column indexes.Tom Lane2013-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When considering a non-last column in a multi-column GiST index, gistsplit.c tries to improve on the split chosen by the opclass-specific pickSplit function by considering penalties for the next column. However, there were two bugs in this code: it failed to recompute the union keys for the leftmost index columns, even though these might well change after reassigning tuples; and it included the old union keys in the recomputation for the columns it did recompute, so that those keys couldn't get smaller even if they should. The first problem could result in an invalid index in which searches wouldn't find index entries that are in fact present; the second would make the index less efficient to search. Both of these errors were caused by misuse of gistMakeUnionItVec, whose API was designed in a way that just begged such errors to be made. There is no situation in which it's safe or useful to compute the union keys for a subset of the index columns, and there is no caller that wants any previous union keys to be included in the computation; so the undocumented choice to treat the union keys as in/out rather than pure output parameters is a waste of code as well as being dangerous. Hence, rather than just making a minimal patch, I've changed the API of gistMakeUnionItVec to remove the "startkey" parameter (it now always processes all index columns) and treat the attr/isnull arrays as purely output parameters. In passing, also get rid of a couple of unnecessary and dangerous uses of static variables in gistutil.c. It's remarkable that the one in gistMakeUnionKey hasn't given us portability troubles before now, because in addition to posing a re-entrancy hazard, it was unsafely assuming that a static char[] array would have at least Datum alignment. Per investigation of a trouble report from Tomas Vondra. (There are also some bugs in contrib/btree_gist to be fixed, but that seems like material for a separate patch.) Back-patch to all supported branches.
* Fix rare missing cancellations in Hot Standby.Simon Riggs2013-01-24
| | | | | | | | | | | | The machinery around XLOG_HEAP2_CLEANUP_INFO failed to correctly pass through the necessary information on latestRemovedXid, avoiding cancellations in some infrequent concurrent update/cleanup scenarios. Backpatchable fix to 9.0 Detailed bug report and fix by Noah Misch, backpatchable version by me.
* Fix recycling of WAL segments after changing recovery target timeline.Heikki Linnakangas2012-12-20
| | | | | | | | | | | | | | | | | | | | | | | | | After the recovery target timeline is changed, we would still recycle and preallocate WAL segments on the old target timeline. Those WAL segments created for the old timeline are a waste of space, although otherwise harmless. The problem is that when installing a recycled WAL segment as a future one, ThisTimeLineID is used to construct the filename. ThisTimeLineID is initialized in the checkpointer process to the recovery target timeline at startup, but it was not updated when the startup process chooses a new target timeline (recovery_target_timeline='latest'). To fix, always update ThisTimeLineID before recycling WAL segments at a restartpoint. This still leaves a small window where we might install WAL segments under wrong timeline ID, if the target timeline is changed just as we're about to start recycling. Also, when we're not on the target timeline yet, but still replaying some older timeline, we'll install WAL segments to the newer timeline anyway and they will still go wasted. We'll just live with the waste in that situation. Commit to 9.2 and 9.1. Older versions didn't change recovery target timeline after startup, and for master, I'll commit a slightly different variant of this.
* Consistency check should compare last record replayed, not last record read.Heikki Linnakangas2012-12-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | EndRecPtr is the last record that we've read, but not necessarily yet replayed. CheckRecoveryConsistency should compare minRecoveryPoint with the last replayed record instead. This caused recovery to think it's reached consistency too early. Now that we do the check in CheckRecoveryConsistency correctly, we have to move the call of that function to after redoing a record. The current place, after reading a record but before replaying it, is wrong. In particular, if there are no more records after the one ending at minRecoveryPoint, we don't enter hot standby until one extra record is generated and read by the standby, and CheckRecoveryConsistency is called. These two bugs conspired to make the code appear to work correctly, except for the small window between reading the last record that reaches minRecoveryPoint, and replaying it. In the passing, rename recoveryLastRecPtr, which is the last record replayed, to lastReplayedEndRecPtr. This makes it slightly less confusing with replayEndRecPtr, which is the last record read that we're about to replay. Original report from Kyotaro HORIGUCHI, further diagnosis by Fujii Masao. Backpatch to 9.0, where Hot Standby subtly changed the test from "minRecoveryPoint < EndRecPtr" to "minRecoveryPoint <= EndRecPtr". The former works because where the test is performed, we have always read one more record than we've replayed.
* Update minimum recovery point on truncation.Heikki Linnakangas2012-12-10
| | | | | | | | | If a file is truncated, we must update minRecoveryPoint. Once a file is truncated, there's no going back; it would not be safe to stop recovery at a point earlier than that anymore. Per report from Kyotaro HORIGUCHI. Backpatch to 8.4. Before that, minRecoveryPoint was not updated during recovery at all.
* Ensure recovery pause feature doesn't pause unless users can connect.Tom Lane2012-12-05
| | | | | | | | | | | | | | | | | | | | | | | | | | If we're not in hot standby mode, then there's no way for users to connect to reset the recoveryPause flag, so we shouldn't pause. The code was aware of this but the test to see if pausing was safe was seriously inadequate: it wasn't paying attention to reachedConsistency, and besides what it was testing was that we could legally enter hot standby, not that we have done so. Get rid of that in favor of checking LocalHotStandbyActive, which because of the coding in CheckRecoveryConsistency is tantamount to checking that we have told the postmaster to enter hot standby. Also, move the recoveryPausesHere() call that reacts to asynchronous recoveryPause requests so that it's not in the middle of application of a WAL record. I put it next to the recoveryStopsHere() call --- in future those are going to need to interact significantly, so this seems like a good waystation. Also, don't bother trying to read another WAL record if we've already decided not to continue recovery. This was no big deal when the code was written originally, but now that reading a record might entail actions like fetching an archive file, it seems a bit silly to do it like that. Per report from Jeff Janes and subsequent discussion. The pause feature needs quite a lot more work, but this gets rid of some indisputable bugs, and seems safe enough to back-patch.
* Don't advance checkPoint.nextXid near the end of a checkpoint sequence.Tom Lane2012-12-02
| | | | | | | | | | | | | | | | | | | | | | This reverts commit c11130690d6dca64267201a169cfb38c1adec5ef in favor of actually fixing the problem: namely, that we should never have been modifying the checkpoint record's nextXid at this point to begin with. The nextXid should match the state as of the checkpoint's logical WAL position (ie the redo point), not the state as of its physical position. It's especially bogus to advance it in some wal_levels and not others. In any case there is no need for the checkpoint record to carry the same nextXid shown in the XLOG_RUNNING_XACTS record just emitted by LogStandbySnapshot, as any replay operation will already have adopted that value as current. This fixes bug #7710 from Tarvi Pillessaar, and probably also explains bug #6291 from Daniel Farina, in that if a checkpoint were in progress at the instant of XID wraparound, the epoch bump would be lost as reported. (And, of course, these days there's at least a 50-50 chance of a checkpoint being in progress at any given instant.) Diagnosed by me and independently by Andres Freund. Back-patch to all branches supporting hot standby.
* XidEpoch++ if wraparound during checkpoint.Simon Riggs2012-12-02
| | | | | | | | | | | | | | | | If wal_level = hot_standby we update the checkpoint nextxid, though in the case where a wraparound occurred half-way through a checkpoint we would neglect updating the epoch also. Updating the nextxid is arguably the wrong thing to do, but changing that may introduce subtle bugs into hot standby startup, while updating the value doesn't cause any known bugs yet. Minimal fix now to HEAD and backbranches, wider fix later in HEAD. Bug reported in #6291 by Daniel Farina and slightly differently in Cause analysis and recommended fixes from Tom Lane and Andres Freund. Applied patch is minimal version of Andres Freund's work.
* 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