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* In XLogReadBufferExtended, don't assume P_NEW yields consecutive pages.Tom Lane2014-02-12
| | | | | | | | | | | | | | | | | | | | | | | | | In a database that's not yet reached consistency, it's possible that some segments of a relation are not full-size but are not the last ones either. Because of the way smgrnblocks() works, asking for a new page with P_NEW will fill in the last not-full-size segment --- and if that makes it full size, the apparent EOF of the relation will increase by more than one page, so that the next P_NEW request will yield a page past the next consecutive one. This breaks the relation-extension logic in XLogReadBufferExtended, possibly allowing a page update to be applied to some page far past where it was intended to go. This appears to be the explanation for reports of table bloat on replication slaves compared to their masters, and probably explains some corrupted-slave reports as well. Fix the loop to check the page number it actually got, rather than merely Assert()'ing that dead reckoning got it to the desired place. AFAICT, there are no other places that make assumptions about exactly which page they'll get from P_NEW. Problem identified by Greg Stark, though this is not the same as his proposed patch. It's been like this for a long time, so back-patch to all supported branches.
* Fix multiple bugs in index page locking during hot-standby WAL replay.Tom Lane2014-01-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In ordinary operation, VACUUM must be careful to take a cleanup lock on each leaf page of a btree index; this ensures that no indexscans could still be "in flight" to heap tuples due to be deleted. (Because of possible index-tuple motion due to concurrent page splits, it's not enough to lock only the pages we're deleting index tuples from.) In Hot Standby, the WAL replay process must likewise lock every leaf page. There were several bugs in the code for that: * The replay scan might come across unused, all-zero pages in the index. While btree_xlog_vacuum itself did the right thing (ie, nothing) with such pages, xlogutils.c supposed that such pages must be corrupt and would throw an error. This accounts for various reports of replication failures with "PANIC: WAL contains references to invalid pages". To fix, add a ReadBufferMode value that instructs XLogReadBufferExtended not to complain when we're doing this. * btree_xlog_vacuum performed the extra locking if standbyState == STANDBY_SNAPSHOT_READY, but that's not the correct test: we won't open up for hot standby queries until the database has reached consistency, and we don't want to do the extra locking till then either, for fear of reading corrupted pages (which bufmgr.c would complain about). Fix by exporting a new function from xlog.c that will report whether we're actually in hot standby replay mode. * To ensure full coverage of the index in the replay scan, btvacuumscan would emit a dummy WAL record for the last page of the index, if no vacuuming work had been done on that page. However, if the last page of the index is all-zero, that would result in corruption of said page, since the functions called on it weren't prepared to handle that case. There's no need to lock any such pages, so change the logic to target the last normal leaf page instead. The first two of these bugs were diagnosed by Andres Freund, the other one by me. Fixes based on ideas from Heikki Linnakangas and myself. This has been wrong since Hot Standby was introduced, so back-patch to 9.0.
* Fix pause_at_recovery_target + recovery_target_inclusive combination.Heikki Linnakangas2014-01-08
| | | | | | | | | | | | If pause_at_recovery_target is set, recovery pauses *before* applying the target record, even if recovery_target_inclusive is set. If you then continue with pg_xlog_replay_resume(), it will apply the target record before ending recovery. In other words, if you log in while it's paused and verify that the database looks OK, ending recovery changes its state again, possibly destroying data that you were tring to salvage with PITR. Backpatch to 9.1, this has been broken since pause_at_recovery_target was added.
* Fix bug in determining when recovery has reached consistency.Heikki Linnakangas2014-01-08
| | | | | | | | | | | | | | | | | | | | | | | | | | When starting WAL replay from an online checkpoint, the last replayed WAL record variable was initialized using the checkpoint record's location, even though the records between the REDO location and the checkpoint record had not been replayed yet. That was noted as "slightly confusing" but harmless in the comment, but in some cases, it fooled CheckRecoveryConsistency to incorrectly conclude that we had already reached a consistent state immediately at the beginning of WAL replay. That caused the system to accept read-only connections in hot standby mode too early, and also PANICs with message "WAL contains references to invalid pages". Fix by initializing the variables to the REDO location instead. In 9.2 and above, change CheckRecoveryConsistency() to use lastReplayedEndRecPtr variable when checking if backup end location has been reached. It was inconsistently using EndRecPtr for that check, but lastReplayedEndRecPtr when checking min recovery point. It made no difference before this patch, because in all the places where CheckRecoveryConsistency was called the two variables were the same, but it was always an accident waiting to happen, and would have been wrong after this patch anyway. Report and analysis by Tomonari Katsumata, bug #8686. Backpatch to 9.0, where hot standby was introduced.
* Move permissions check from do_pg_start_backup to pg_start_backupMagnus Hagander2014-01-07
| | | | | | | | | | And the same for do_pg_stop_backup. The code in do_pg_* is not allowed to access the catalogs. For manual base backups, the permissions check can be handled in the calling function, and for streaming base backups only users with the required permissions can get past the authentication step in the first place. Reported by Antonin Houska, diagnosed by Andres Freund
* 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 memory leaks from accumulating across printtup() calls.Tom Lane2013-11-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Historically, printtup() has assumed that it could prevent memory leakage by pfree'ing the string result of each output function and manually managing detoasting of toasted values. This amounts to assuming that datatype output functions never leak any memory internally; an assumption we've already decided to be bogus elsewhere, for example in COPY OUT. range_out in particular is known to leak multiple kilobytes per call, as noted in bug #8573 from Godfried Vanluffelen. While we could go in and fix that leak, it wouldn't be very notationally convenient, and in any case there have been and undoubtedly will again be other leaks in other output functions. So what seems like the best solution is to run the output functions in a temporary memory context that can be reset after each row, as we're doing in COPY OUT. Some quick experimentation suggests this is actually a tad faster than the retail pfree's anyway. This patch fixes all the variants of printtup, except for debugtup() which is used in standalone mode. It doesn't seem worth worrying about query-lifespan leaks in standalone mode, and fixing that case would be a bit tedious since debugtup() doesn't currently have any startup or shutdown functions. While at it, remove manual detoast management from several other output-function call sites that had copied it from printtup(). This doesn't make a lot of difference right now, but in view of recent discussions about supporting "non-flattened" Datums, we're going to want that code gone eventually anyway. Back-patch to 9.2 where range_out was introduced. We might eventually decide to back-patch this further, but in the absence of known major leaks in older output functions, I'll refrain for now.
* Retry after buffer locking failure during SPGiST index creation.Tom Lane2013-11-02
| | | | | | | | | The original coding thought this case was impossible, but it can happen if the bgwriter or checkpointer processes decide to write out an index page while creation is still proceeding, leading to a bogus "unexpected spgdoinsert() failure" error. Problem reported by Jonathan S. Katz. Teodor Sigaev
* 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.
* 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
* Avoid deadlocks during insertion into SP-GiST indexes.Tom Lane2013-06-14
| | | | | | | | | | | | | SP-GiST's original scheme for avoiding deadlocks during concurrent index insertions doesn't work, as per report from Hailong Li, and there isn't any evident way to make it work completely. We could possibly lock individual inner tuples instead of their whole pages, but preliminary experimentation suggests that the performance penalty would be huge. Instead, if we fail to get a buffer lock while descending the tree, just restart the tree descent altogether. We keep the old tuple positioning rules, though, in hopes of reducing the number of cases where this can happen. Teodor Sigaev, somewhat edited by Tom Lane
* Fix typo in comment.Heikki Linnakangas2013-06-06
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* Backport log_newpage_buffer.Robert Haas2013-06-06
| | | | | Andres' fix for XLOG_HEAP2_VISIBLE on unitialized pages requires this.
* 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 management of fn_extra caching during repeated GiST index scans.Tom Lane2013-05-09
| | | | | | | | | | | | | | Commit d22a09dc70f9830fa78c1cd1a3a453e4e473d354 introduced official support for GiST consistentFns that want to cache data using the FmgrInfo fn_extra pointer: the idea was to preserve the cached values across gistrescan(), whereas formerly they'd been leaked. However, there was an oversight in that, namely that multiple scan keys might reference the same column's consistentFn; the code would result in propagating the same cache value into multiple scan keys, resulting in crashes or wrong answers. Use a separate array instead to ensure that each scan key keeps its own state. Per bug #8143 from Joel Roller. Back-patch to 9.2 where the bug was introduced.
* 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.
* Fix tli history file fetching, broken by the archive after crash recevery patch.Heikki Linnakangas2013-03-07
| | | | | | | | | | | | | | If we were about to enter archive recovery after crash recovery, we scanned the archive for the latest tli history file, and set the recovery target timeline to that. However, when we actually tried to read the history file, we would not fetch the file from the archive, because we were not in archive recovery yet. To fix, make readTimeLineHistory and existsTimeLineHistory to always fetch the file from archive if archive recovery is requested, even if we're not in archive recovery yet. Backpatch to 9.2. Mitsumasa KONDO
* Further fix to the mode where we enter archive recovery after crash recovery.Heikki Linnakangas2013-03-07
| | | | | | | | | | | I missed to returns in the middle of ReadRecord function in my previous fix. If a WAL file was not found at all during crash recovery, XLogPageRead would return 'false', and ReadRecord would return without entering archive recovery. 9.2 only. In master, the code is structured differently and does not have this problem. Kyotaro HORIGUCHI, Mitsumasa KONDO and me.
* Fix SQL function execution to be safe with long-lived FmgrInfos.Tom Lane2013-03-03
| | | | | | | | | | | | fmgr_sql had been designed on the assumption that the FmgrInfo it's called with has only query lifespan. This is demonstrably unsafe in connection with range types, as shown in bug #7881 from Andrew Gierth. Fix things so that we re-generate the function's cache data if the (sub)transaction it was made in is no longer active. Back-patch to 9.2. This might be needed further back, but it's not clear whether the case can realistically arise without range types, so for now I'll desist from back-patching further.
* Fix thinko in previous commit.Heikki Linnakangas2013-02-22
| | | | | | We must still initialize minRecoveryPoint if we start straight with archive recovery, e.g when recovering from a normal base backup taken with pg_start/stop_backup. Otherwise we never consider the system consistent.
* If recovery.conf is created after "pg_ctl stop -m i", do crash recovery.Heikki Linnakangas2013-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If you create a base backup using an atomic filesystem snapshot, and try to perform PITR starting from that base backup, or if you just kill a master server and create recovery.conf to put it into standby mode, we don't know how far we need to recover before reaching consistency. Normally in crash recovery, we replay all the WAL present in pg_xlog, and assume that we're consistent after that. And normally in archive recovery, minRecoveryPoint, backupEndRequired, or backupEndPoint is set in the control file, indicating how far we need to replay to reach consistency. But if the server was previously up and running normally, and you kill -9 it or take an atomic filesystem snapshot, none of those fields are set in the control file. The solution is to perform crash recovery first, replaying all the WAL in pg_xlog. After that's done, we assume that the system is consistent like in normal crash recovery, and switch to archive recovery mode after that. Per report from Kyotaro HORIGUCHI. In his scenario, recovery.conf was created after "pg_ctl stop -m i". I'm not sure we need to support that exact scenario, but we should support backing up using a filesystem snapshot, which looks identical. This issue goes back to at least 9.0, where hot standby was introduced and we started to track when consistency is reached. In 9.1 and 9.2, we would open up for hot standby too early, and queries could briefly see an inconsistent state. But 9.2 made it more visible, as we started to PANIC if we see a reference to a non-existing page during recovery, if we've already reached consistency. This is a fairly big patch, so back-patch to 9.2 only, where the issue is more visible. We can consider back-patching further after this has received some more testing in 9.2 and master.
* Better fix for "unarchived WAL files get deleted on crash recovery" bug.Heikki Linnakangas2013-02-15
| | | | | | | | | | Revert my earlier fix for the bug that unarchived WAL files get deleted on crash recovery, commit c9cc7e05c6d82a9781883a016c70d95aa4923122. We create a .done file for files streamed or restored from archive, so the WAL file recycling logic used during normal operation works just as well during archive recovery. Per Fujii Masao's suggestion.
* Don't delete unarchived WAL files during crash recovery.Heikki Linnakangas2013-02-15
| | | | | Bug reported by Jehan-Guillaume (ioguix) de Rorthais. This was introduced with the change to keep WAL files restored from archive in pg_xlog, in 9.2.
* 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.
* Remove vestigial secondary-split support in gist_box_picksplit().Tom Lane2013-02-10
| | | | | | | | | | | | | | | | | | | | | | | Not only is this implementation of secondary-split not better than the default implementation in gistsplit.c, it's actually worse. The gistsplit.c code at least looks to see if switching the left and right sides would make a better merge with the previously-split tuples, while this doesn't. In any case it's rather useless to support secondary split only in an edge case. There used to be more complete support for it here (in chooseLR()), but that was removed in commit 7f3bd86843e5aad84585a57d3f6b80db3c609916. It appears to me though that the chooseLR() code was really isomorphic to the default implementation, since it was still based on choosing the cheaper way of adding two sub-split vectors that had been chosen without regard to the primary split initially. I think an implementation of secondary split that could beat the default implementation would have to be pretty fully integrated into the split algorithm, not plastered on at the end. Back-patch to 9.2, but not further; previous branches have the chooseLR() code which I don't feel a great need to mess with. This is mainly so we just have two behaviors and not three among the various branches (IOW, this patch is cleanup for commit 7f3bd86843e5aad84585a57d3f6b80db3c609916's incomplete removal of secondary-split support).
* 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.
* Tolerate timeline switches while "pg_basebackup -X fetch" is running.Heikki Linnakangas2013-01-03
| | | | | | | | | | | | | | | | | | | | | | If you take a base backup from a standby server with "pg_basebackup -X fetch", and the timeline switches while the backup is being taken, the backup used to fail with an error "requested WAL segment %s has already been removed". This is because the server-side code that sends over the required WAL files would not construct the WAL filename with the correct timeline after a switch. Fix that by using readdir() to scan pg_xlog for all the WAL segments in the range, regardless of timeline. Also, include all timeline history files in the backup, if taken with "-X fetch". That fixes another related bug: If a timeline switch happened just before the backup was initiated in a standby, the WAL segment containing the initial checkpoint record contains WAL from the older timeline too. Recovery will not accept that without a timeline history file that lists the older timeline. Backpatch to 9.2. Versions prior to that were not affected as you could not take a base backup from a standby before 9.2.
* Keep timeline history files restored from archive in pg_xlog.Heikki Linnakangas2012-12-30
| | | | | | | | | | | | | | | | | | | | | | | The cascading standby patch in 9.2 changed the way WAL files are treated when restored from the archive. Before, they were restored under a temporary filename, and not kept in pg_xlog, but after the patch, they were copied under pg_xlog. This is necessary for a cascading standby to find them, but it also means that if the archive goes offline and a standby is restarted, it can recover back to where it was using the files in pg_xlog. It also means that if you take an offline backup from a standby server, it includes all the required WAL files in pg_xlog. However, the same change was not made to timeline history files, so if the WAL segment containing the checkpoint record contains a timeline switch, you will still get an error if you try to restart recovery without the archive, or recover from an offline backup taken from the standby. With this patch, timeline history files restored from archive are copied into pg_xlog like WAL files are, so that pg_xlog contains all the files required to recover. This is a corner-case pre-existing issue in 9.2, but even more important in master where it's possible for a standby to follow a timeline switch through streaming replication. To make that possible, the timeline history files must be present in pg_xlog.
* Fix grammatical mistake in error messagePeter Eisentraut2012-12-20
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* 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.
* Check if we've reached end-of-backup point also if no redo is required.Heikki Linnakangas2012-12-19
| | | | | | | | | | | | | If you restored from a backup taken from a standby, and the last record in the backup is the checkpoint record, ie. there is no redo required except for the checkpoint record, we would fail to notice that we've reached the end-of-backup point, and the database is consistent. The result was an error "WAL ends before end of online backup". To fix, move the have-we-reached-end-of-backup check into CheckRecoveryConsistency(), which is already responsible for similar checks with minRecoveryPoint, and is called in the right places. Backpatch to 9.2, this check and bug did not exist before that.
* In multi-insert, don't go into infinite loop on a huge tuple and fillfactor.Heikki Linnakangas2012-12-12
| | | | | | | | | | | | | | | | | | If a tuple is larger than page size minus space reserved for fillfactor, heap_multi_insert would never find a page that it fits in and repeatedly ask for a new page from RelationGetBufferForTuple. If a tuple is too large to fit on any page, taking fillfactor into account, RelationGetBufferForTuple will always expand the relation. In a normal insert, heap_insert will accept that and put the tuple on the new page. heap_multi_insert, however, does a fillfactor check of its own, and doesn't accept the newly-extended page RelationGetBufferForTuple returns, even though there is no other choice to make the tuple fit. Fix that by making the logic in heap_multi_insert more like the heap_insert logic. The first tuple is always put on the page RelationGetBufferForTuple gives us, and the fillfactor check is only applied to the subsequent tuples. Report from David Gould, although I didn't use his patch.
* 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.
* Must not reach consistency before XLOG_BACKUP_RECORDSimon Riggs2012-12-05
| | | | | | | | | | When waiting for an XLOG_BACKUP_RECORD the minRecoveryPoint will be incorrect, so we must not declare recovery as consistent before we have seen the record. Major bug allowing recovery to end too early in some cases, allowing people to see inconsistent db. This patch to HEAD and 9.2, other fix required for 9.1 and 9.0 Simon Riggs and Andres Freund, bug report by Jeff Janes