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* Fix copy & paste mistake in pg_get_replication_slots().Andres Freund2015-08-10
| | | | | | | | XLogRecPtr was compared with InvalidTransactionId instead of InvalidXLogRecPtr. As both are defined to the same value this doesn't cause any actual problems, but it's still wrong. Backpatch: 9.4-master, bug was introduced in 9.4
* Don't start to stream after pg_receivexlog --create-slot.Andres Freund2015-08-10
| | | | | | | | | | | Immediately starting to stream after --create-slot is inconvenient in a number of situations (e.g. when configuring a slot for use in recovery.conf) and it's easy to just call pg_receivexlog twice in the rest of the cases. Author: Michael Paquier Discussion: CAB7nPqQ9qEtuDiKY3OpNzHcz5iUA+DUX9FcN9K8GUkCZvG7+Ew@mail.gmail.com Backpatch: 9.5, where the option was introduced
* Remove gram.y's precedence declaration for OVERLAPS.Tom Lane2015-08-09
| | | | | | | | | | | | | | | | | The allowed syntax for OVERLAPS, viz "row OVERLAPS row", is sufficiently constrained that we don't actually need a precedence declaration for OVERLAPS; indeed removing this declaration does not change the generated gram.c file at all. Let's remove it to avoid confusion about whether OVERLAPS has precedence or not. If we ever generalize what we allow for OVERLAPS, we might need to put back a precedence declaration for it, but we might want some other level than what it has today --- and leaving the declaration there would just risk confusion about whether that would be an incompatible change. Likewise, remove OVERLAPS from the documentation's precedence table. Per discussion with Noah Misch. Back-patch to 9.5 where we hacked up some nearby precedence decisions.
* Fix typo in LDAP exampleMagnus Hagander2015-08-09
| | | | Reported by William Meitzen
* Fix broken multibyte regression tests.Tatsuo Ishii2015-08-09
| | | | | | | | | commit 9043Fe390f4f0b4586cfe59cbd22314b9c3e2957 broke multibyte regression tests because the commit removes the warning message when temporary hash indexes is created, which has been added by commit 07af523870bcfe930134054febd3a6a114942e5b. Back patched to 9.5 stable tree.
* docs: fix typo in rules.sgmlBruce Momjian2015-08-08
| | | | | | | | Report by Dean Rasheed Patch by Dean Rasheed Backpatch through 9.5
* 9.5 release notes: add increase buffer mapping partitions itemBruce Momjian2015-08-08
| | | | | | Report by Robert Haas, Andres Freund Backpatch through 9.5
* Further adjustments to PlaceHolderVar removal.Tom Lane2015-08-07
| | | | | | | | | | | | | | | | | | | | | | | | A new test case from Andreas Seltenreich showed that we were still a bit confused about removing PlaceHolderVars during join removal. Specifically, remove_rel_from_query would remove a PHV that was used only underneath the removable join, even if the place where it's used was the join partner relation and not the join clause being deleted. This would lead to a "too late to create a new PlaceHolderInfo" error later on. We can defend against that by checking ph_eval_at to see if the PHV could possibly be getting used at some partner rel. Also improve some nearby LATERAL-related logic. I decided that the check on ph_lateral needed to take precedence over the check on ph_needed, in case there's a lateral reference underneath the join being considered. (That may be impossible, but I'm not convinced of it, and it's easy enough to defend against the case.) Also, I realized that remove_rel_from_query's logic for updating LateralJoinInfos is dead code, because we don't build those at all until after join removal. Back-patch to 9.3. Previous versions didn't have the LATERAL issues, of course, and they also didn't attempt to remove PlaceHolderInfos during join removal. (I'm starting to wonder if changing that was really such a great idea.)
* Fix attach-related race condition in shm_mq_send_bytes.Robert Haas2015-08-07
| | | | Spotted by Antonin Houska.
* Address points made in post-commit review of replication origins.Andres Freund2015-08-07
| | | | | | | | | | Amit reviewed the replication origins patch and made some good points. Address them. This fixes typos in error messages, docs and comments and adds a missing error check (although in a should-never-happen scenario). Discussion: CAA4eK1JqUBVeWWKwUmBPryFaje4190ug0y-OAUHWQ6tD83V4xg@mail.gmail.com Backpatch: 9.5, where replication origins were introduced.
* 9.5 release notes: updates from Andres Freund and Jeff JanesBruce Momjian2015-08-06
| | | | | | Report by Andres Freund and Jeff Janes Backpatch through 9.5
* Fix old oversight in join removal logic.Tom Lane2015-08-06
| | | | | | | | | | | | | Commit 9e7e29c75ad441450f9b8287bd51c13521641e3b introduced an Assert that join removal didn't reduce the eval_at set of any PlaceHolderVar to empty. At first glance it looks like join_is_removable ensures that's true --- but actually, the loop in join_is_removable skips PlaceHolderVars that are not referenced above the join due to be removed. So, if we don't want any empty eval_at sets, the right thing to do is to delete any now-unreferenced PlaceHolderVars from the data structure entirely. Per fuzz testing by Andreas Seltenreich. Back-patch to 9.3 where the aforesaid Assert was added.
* 9.5 release notes: mention ON CONFLICT DO NOTHING for FDWsBruce Momjian2015-08-06
| | | | | | Report by Peter Geoghegan Backpatch through 9.5
* Fix eclass_useful_for_merging to give valid results for appendrel children.Tom Lane2015-08-06
| | | | | | | | | | | | | | | | | | | | Formerly, this function would always return "true" for an appendrel child relation, because it would think that the appendrel parent was a potential join target for the child. In principle that should only lead to some inefficiency in planning, but fuzz testing by Andreas Seltenreich disclosed that it could lead to "could not find pathkey item to sort" planner errors in odd corner cases. Specifically, we would think that all columns of a child table's multicolumn index were interesting pathkeys, causing us to generate a MergeAppend path that sorts by all the columns. However, if any of those columns weren't actually used above the level of the appendrel, they would not get added to that rel's targetlist, which would result in being unable to resolve the MergeAppend's sort keys against its targetlist during createplan.c. Backpatch to 9.3. In older versions, columns of an appendrel get added to its targetlist even if they're not mentioned above the scan level, so that the failure doesn't occur. It might be worth back-patching this fix to older versions anyway, but I'll refrain for the moment.
* 9.5 release notes: mention change to CRC-32CBruce Momjian2015-08-06
| | | | | | Report by Andres Freund Backpatch through 9.5
* 9.5 release notes: adjustments suggested by Andres FreundBruce Momjian2015-08-06
| | | | | | Report by Andres Freund Backpatch through 9.5
* 9.5 release notes: add non-LEAKPROOF view pushdown mentionBruce Momjian2015-08-06
| | | | | | Report by Dean Rasheed Backpatch through 9.5
* Further fixes for degenerate outer join clauses.Tom Lane2015-08-06
| | | | | | | | | | | | | | | | | | | | | | | | | | Further testing revealed that commit f69b4b9495269cc4 was still a few bricks shy of a load: minor tweaking of the previous test cases resulted in the same wrong-outer-join-order problem coming back. After study I concluded that my previous changes in make_outerjoininfo() were just accidentally masking the problem, and should be reverted in favor of forcing syntactic join order whenever an upper outer join's predicate doesn't mention a lower outer join's LHS. This still allows the chained-outer-joins style that is the normally optimizable case. I also tightened things up some more in join_is_legal(). It seems to me on review that what's really happening in the exception case where we ignore a mismatched special join is that we're allowing the proposed join to associate into the RHS of the outer join we're comparing it to. As such, we should *always* insist that the proposed join be a left join, which eliminates a bunch of rather dubious argumentation. The case where we weren't enforcing that was the one that was already known buggy anyway (it had a violatable Assert before the aforesaid commit) so it hardly deserves a lot of deference. Back-patch to all active branches, like the previous patch. The added regression test case failed in all branches back to 9.1, and I think it's only an unrelated change in costing calculations that kept 9.0 from choosing a broken plan.
* Fix incorrect calculation in shm_mq_receive.Robert Haas2015-08-06
| | | | | | | | | If some, but not all, of the length word has already been read, and the next attempt to read sees exactly the number of bytes needed to complete the length word, or fewer, then we'll incorrectly read less than all of the available data. Antonin Houska
* Fix `make installcheck` for serializable transactions.Kevin Grittner2015-08-06
| | | | | | | | | | | | | | | | | | | | | Commit e5550d5fec66aa74caad1f79b79826ec64898688 added some new tests for ALTER TABLE which involved table scans. When default_transaction_isolation = 'serializable' these acquire relation-level SIReadLocks. The test results didn't cope with that. Add SIReadLock as the minimum lock level for purposes of these tests. This could also be fixed by excluding this type of lock from the my_locks view, but it would be a bug for SIReadLock to show up for a relation which was not otherwise locked, so do it this way to allow that sort of condition to cause a regression test failure. There is some question whether we could avoid taking SIReadLocks during these operations, but confirming the safety of that and figuring out how to avoid the locks is not trivial, and would be a separate patch. Backpatch to 9.4 where the new tests were added.
* Improve includes introduced in the replication origins patch.Andres Freund2015-08-06
| | | | | | | | pg_resetxlog.h contained two superfluous includes, origin.h superfluously depended on logical.h, and pg_xlogdump's rmgrdesc.h only indirectly included origin.h. Backpatch: 9.5, where replication origins were introduced.
* Reconcile nodes/*funcs.c with recent work.Noah Misch2015-08-05
| | | | | | | | | A few of the discrepancies had semantic significance, but I did not track down the resulting user-visible bugs, if any. Back-patch to 9.5, where all but one discrepancy appeared. The _equalCreateEventTrigStmt() situation dates to 9.3 but does not affect semantics. catversion bump due to readfuncs.c field order changes.
* Link $(WIN32RES) into single-file modules only when PGFILEDESC is set.Noah Misch2015-08-05
| | | | | | | | | | Commit 0ffc201a51395ca71fe429ef86c872850a5850ee included this object unconditionally. Being unprepared for that, most external, single-file modules failed to build. This better aligns the GNU make build system with the heuristic in the MSVC build's Project::AddDirResourceFile(). In-tree, installed modules set PGFILEDESC, so they will see no change. Also, under PGXS, omit the nonfunctioning rule to build win32ver.rc. Back-patch to 9.5, where the aforementioned commit first appeared.
* Fix BRIN to use SnapshotAny during summarizationAlvaro Herrera2015-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For correctness of summarization results, it is critical that the snapshot used during the summarization scan is able to see all tuples that are live to all transactions -- including tuples inserted or deleted by in-progress transactions. Otherwise, it would be possible for a transaction to insert a tuple, then idle for a long time while a concurrent transaction executes summarization of the range: this would result in the inserted value not being considered in the summary. Previously we were trying to use a MVCC snapshot in conjunction with adding a "placeholder" tuple in the index: the snapshot would see all committed tuples, and the placeholder tuple would catch insertions by any new inserters. The hole is that prior insertions by transactions that are still in progress by the time the MVCC snapshot was taken were ignored. Kevin Grittner reported this as a bogus error message during vacuum with default transaction isolation mode set to repeatable read (because the error report mentioned a function name not being invoked during), but the problem is larger than that. To fix, tweak IndexBuildHeapRangeScan to have a new mode that behaves the way we need using SnapshotAny visibility rules. This change simplifies the BRIN code a bit, mainly by removing large comments that were mistaken. Instead, rely on the SnapshotAny semantics to provide what it needs. (The business about a placeholder tuple needs to remain: that covers the case that a transaction inserts a a tuple in a page that summarization already scanned.) Discussion: https://www.postgresql.org/message-id/20150731175700.GX2441@postgresql.org In passing, remove a couple of unused declarations from brin.h and reword a comment to be proper English. This part submitted by Kevin Grittner. Backpatch to 9.5, where BRIN was introduced.
* Make real sure we don't reassociate joins into or out of SEMI/ANTI joins.Tom Lane2015-08-05
| | | | | | | | | | | | | | | | Per the discussion in optimizer/README, it's unsafe to reassociate anything into or out of the RHS of a SEMI or ANTI join. An example from Piotr Stefaniak showed that join_is_legal() wasn't sufficiently enforcing this rule, so lock it down a little harder. I couldn't find a reasonably simple example of the optimizer trying to do this, so no new regression test. (Piotr's example involved the random search in GEQO accidentally trying an invalid case and triggering a sanity check way downstream in clause selectivity estimation, which did not seem like a sequence of events that would be useful to memorialize in a regression test as-is.) Back-patch to all active branches.
* Fix debug message output when connecting to a logical slot.Andres Freund2015-08-05
| | | | | | | | | | Previously the message erroneously printed the same LSN twice as the assignment to the start_lsn variable was before the message. Correct that. Reported-By: Marko Tiikkaja Author: Marko Tiikkaja Backpatch: 9.5, where logical decoding was introduced
* Fix comment atomics.h.Andres Freund2015-08-05
| | | | | | | | | I appear to accidentally have switched the comments for pg_atomic_write_u32 and pg_atomic_read_u32 around. Also fix some minor typos I found while fixing. Noticed-By: Amit Kapila Backpatch: 9.5
* Docs: add an explicit example about controlling overall greediness of REs.Tom Lane2015-08-04
| | | | Per discussion of bug #13538.
* Fix pg_dump to dump shell types.Tom Lane2015-08-04
| | | | | | | | | | | Per discussion, it really ought to do this. The original choice to exclude shell types was probably made in the dark ages before we made it harder to accidentally create shell types; but that was in 7.3. Also, cause the standard regression tests to leave a shell type behind, for convenience in testing the case in pg_dump and pg_upgrade. Back-patch to all supported branches.
* Fix bogus "out of memory" reports in tuplestore.c.Tom Lane2015-08-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The tuplesort/tuplestore memory management logic assumed that the chunk allocation overhead for its memtuples array could not increase when increasing the array size. This is and always was true for tuplesort, but we (I, I think) blindly copied that logic into tuplestore.c without noticing that the assumption failed to hold for the much smaller array elements used by tuplestore. Given rather small work_mem, this could result in an improper complaint about "unexpected out-of-memory situation", as reported by Brent DeSpain in bug #13530. The easiest way to fix this is just to increase tuplestore's initial array size so that the assumption holds. Rather than relying on magic constants, though, let's export a #define from aset.c that represents the safe allocation threshold, and make tuplestore's calculation depend on that. Do the same in tuplesort.c to keep the logic looking parallel, even though tuplesort.c isn't actually at risk at present. This will keep us from breaking it if we ever muck with the allocation parameters in aset.c. Back-patch to all supported versions. The error message doesn't occur pre-9.3, not so much because the problem can't happen as because the pre-9.3 tuplestore code neglected to check for it. (The chance of trouble is a great deal larger as of 9.3, though, due to changes in the array-size-increasing strategy.) However, allowing LACKMEM() to become true unexpectedly could still result in less-than-desirable behavior, so let's patch it all the way back.
* Fix a PlaceHolderVar-related oversight in star-schema planning patch.Tom Lane2015-08-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit b514a7460d9127ddda6598307272c701cbb133b7, I changed the planner so that it would allow nestloop paths to remain partially parameterized, ie the inner relation might need parameters from both the current outer relation and some upper-level outer relation. That's fine so long as we're talking about distinct parameters; but the patch also allowed creation of nestloop paths for cases where the inner relation's parameter was a PlaceHolderVar whose eval_at set included the current outer relation and some upper-level one. That does *not* work. In principle we could allow such a PlaceHolderVar to be evaluated at the lower join node using values passed down from the upper relation along with values from the join's own outer relation. However, nodeNestloop.c only supports simple Vars not arbitrary expressions as nestloop parameters. createplan.c is also a few bricks shy of being able to handle such cases; it misplaces the PlaceHolderVar parameters in the plan tree, which is why the visible symptoms of this bug are "plan should not reference subplan's variable" and "failed to assign all NestLoopParams to plan nodes" planner errors. Adding the necessary complexity to make this work doesn't seem like it would be repaid in significantly better plans, because in cases where such a PHV exists, there is probably a corresponding join order constraint that would allow a good plan to be found without using the star-schema exception. Furthermore, adding complexity to nodeNestloop.c would create a run-time penalty even for plans where this whole consideration is irrelevant. So let's just reject such paths instead. Per fuzz testing by Andreas Seltenreich; the added regression test is based on his example query. Back-patch to 9.2, like the previous patch.
* Cap wal_buffers to avoid a server crash when it's set very large.Robert Haas2015-08-04
| | | | | | | | | | It must be possible to multiply wal_buffers by XLOG_BLCKSZ without overflowing int, or calculations in StartupXLOG will go badly wrong and crash the server. Avoid that by imposing a maximum value on wal_buffers. This will be just under 2GB, assuming the usual value for XLOG_BLCKSZ. Josh Berkus, per an analysis by Andrew Gierth.
* Update comment to match behavior of latest code.Robert Haas2015-08-04
| | | | Peter Geoghegan
* Stamp 9.5alpha2.REL9_5_ALPHA2Tom Lane2015-08-03
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* RLS: Keep deny policy when only restrictive existStephen Frost2015-08-03
| | | | | | | | | | | | | | | Only remove the default deny policy when a permissive policy exists (either from the hook or defined by the user). If only restrictive policies exist then no rows will be visible, as restrictive policies shouldn't make rows visible. To address this requirement, a single "USING (true)" permissive policy can be created. Update the test_rls_hooks regression tests to create the necessary "USING (true)" permissive policy. Back-patch to 9.5 where RLS was added. Per discussion with Dean.
* Translation updatesPeter Eisentraut2015-08-03
| | | | | Source-Git-URL: git://git.postgresql.org/git/pgtranslation/messages.git Source-Git-Hash: 01a9485e7f9d18e1195250ec68634f1d3c9497f6
* Update 9.5 release notes through today.Tom Lane2015-08-03
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* Fix psql \d output of policies.Joe Conway2015-08-03
| | | | | | psql neglected to wrap parenthesis around USING and WITH CHECK expressions -- fixed. Back-patched to 9.5 where RLS policies were introduced.
* Make recovery rename tablespace_map to *.old if backup_label is not present.Fujii Masao2015-08-03
| | | | | | | | | | | | | | | If tablespace_map file is present without backup_label file, there is no use of such file. There is no harm in retaining it, but it is better to get rid of the map file so that we don't have any redundant file in data directory and it will avoid any sort of confusion. It seems prudent though to just rename the file out of the way rather than delete it completely, also we ignore any error that occurs in rename operation as even if map file is present without backup_label file, it is harmless. Back-patch to 9.5 where tablespace_map file was introduced. Amit Kapila, reviewed by Robert Haas, Alvaro Herrera and me.
* Fix pg_rewind when pg_xlog is a symlink.Heikki Linnakangas2015-08-03
| | | | | | | | | | pg_xlog is often a symlink, typically to a different filesystem. Don't get confused and comlain about by that, and just always pretend that it's a normal directory, even if it's really a symlink. Also add a test case for this. Backpatch to 9.5.
* Clean up pg_rewind regression test script.Heikki Linnakangas2015-08-03
| | | | | | | | | | Since commit 01f6bb4b2, TestLib.pm has exported path to tmp_check directory, so let's use that also for the pg_rewind test clusters etc. Also, in master, the $tempdir_short variable has not been used since commit 13d856e17, which moved the initdb-running code to TestLib.pm. Backpatch to 9.5.
* Make modules/test_ddl_deparse/.gitignore match its siblings.Tom Lane2015-08-03
| | | | | Not sure why /tmp_check/ was omitted from this one, but even if it isn't really needed right now, it's inconsistent not to include it.
* contrib/isn now needs a .gitignore file.Tom Lane2015-08-02
| | | | | Oversight in commit cb3384a0cb4cf900622b77865f60e31259923079. Back-patch to 9.1, like that commit.
* Fix a number of places that produced XX000 errors in the regression tests.Tom Lane2015-08-02
| | | | | | | | | | | | | | | | | | | | It's against project policy to use elog() for user-facing errors, or to omit an errcode() selection for errors that aren't supposed to be "can't happen" cases. Fix all the violations of this policy that result in ERRCODE_INTERNAL_ERROR log entries during the standard regression tests, as errors that can reliably be triggered from SQL surely should be considered user-facing. I also looked through all the files touched by this commit and fixed other nearby problems of the same ilk. I do not claim to have fixed all violations of the policy, just the ones in these files. In a few places I also changed existing ERRCODE choices that didn't seem particularly appropriate; mainly replacing ERRCODE_SYNTAX_ERROR by something more specific. Back-patch to 9.5, but no further; changing ERRCODE assignments in stable branches doesn't seem like a good idea.
* Avoid calling memcpy() with a NULL source pointer and count == 0.Tom Lane2015-08-02
| | | | | | | | | | | | | | | | As in commit 0a52d378b03b7d5a, avoid doing something that has undefined results according to the C standard, even though in practice there does not seem to be any problem with it. This fixes two places in numeric.c that demonstrably could call memcpy() with such arguments. I looked through that file and didn't see any other places with similar hazards; this is not to claim that there are not such places in other files. Per report from Piotr Stefaniak. Back-patch to 9.5 which is where the previous commit was added. We're more or less setting a precedent that we will not worry about this type of issue in pre-9.5 branches unless someone demonstrates a problem in the field.
* Fix output of ISBN-13 numbers beginning with 979.Heikki Linnakangas2015-08-02
| | | | | | | | | | | | | An EAN beginning with 979 (but not 9790 - those are ISMN's) are accepted as ISBN numbers, but they cannot be represented in the old, 10-digit ISBN format. They must be output in the new 13-digit ISBN-13 format. We printed out an incorrect value for those. Also add a regression test, to test this and some other basic functionality of the module. Patch by Fabien Coelho. This fixes bug #13442, reported by B.Z. Backpatch to 9.1, where we started to recognize ISBN-13 numbers.
* Fix incorrect order of lock file removal and failure to close() sockets.Tom Lane2015-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | Commit c9b0cbe98bd783e24a8c4d8d8ac472a494b81292 accidentally broke the order of operations during postmaster shutdown: it resulted in removing the per-socket lockfiles after, not before, postmaster.pid. This creates a race-condition hazard for a new postmaster that's started immediately after observing that postmaster.pid has disappeared; if it sees the socket lockfile still present, it will quite properly refuse to start. This error appears to be the explanation for at least some of the intermittent buildfarm failures we've seen in the pg_upgrade test. Another problem, which has been there all along, is that the postmaster has never bothered to close() its listen sockets, but has just allowed them to close at process death. This creates a different race condition for an incoming postmaster: it might be unable to bind to the desired listen address because the old postmaster is still incumbent. This might explain some odd failures we've seen in the past, too. (Note: this is not related to the fact that individual backends don't close their client communication sockets. That behavior is intentional and is not changed by this patch.) Fix by adding an on_proc_exit function that closes the postmaster's ports explicitly, and (in 9.3 and up) reshuffling the responsibility for where to unlink the Unix socket files. Lock file unlinking can stay where it is, but teach it to unlink the lock files in reverse order of creation.
* Fix race condition that lead to WALInsertLock deadlock with commit_delay.Heikki Linnakangas2015-08-02
| | | | | | | | | | | | | | | | | If a call to WaitForXLogInsertionsToFinish() returned a value in the middle of a page, and another backend then started to insert a record to the same page, and then you called WaitXLogInsertionsToFinish() again, the second call might return a smaller value than the first call. The problem was in GetXLogBuffer(), which always updated the insertingAt value to the beginning of the requested page, not the actual requested location. Because of that, the second call might return a xlog pointer to the beginning of the page, while the first one returned a later position on the same page. XLogFlush() performs two calls to WaitXLogInsertionsToFinish() in succession, and holds WALWriteLock on the second call, which can deadlock if the second call to WaitXLogInsertionsToFinish() blocks. Reported by Spiros Ioannou. Backpatch to 9.4, where the more scalable WALInsertLock mechanism, and this bug, was introduced.
* Micro optimize LWLockAttemptLock() a bit.Andres Freund2015-08-02
| | | | | | | | | | | | LWLockAttemptLock pointlessly read the lock's state in every loop iteration, even though pg_atomic_compare_exchange_u32() returns the old value. Instead do that only once before the loop iteration. Additionally there's no need to have the expected_state variable, old_state mostly had the same value anyway. Noticed-By: Heikki Linnakangas Backpatch: 9.5, no reason to let the branches diverge at this point
* Fix issues around the "variable" support in the lwlock infrastructure.Andres Freund2015-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | The lwlock scalability work introduced two race conditions into the lwlock variable support provided for xlog.c. First, and harmlessly on most platforms, it set/read the variable without the spinlock in some places. Secondly, due to the removal of the spinlock, it was possible that a backend missed changes to the variable's state if it changed in the wrong moment because checking the lock's state, the variable's state and the queuing are not protected by a single spinlock acquisition anymore. To fix first move resetting the variable's from LWLockAcquireWithVar to WALInsertLockRelease, via a new function LWLockReleaseClearVar. That prevents issues around waiting for a variable's value to change when a new locker has acquired the lock, but not yet set the value. Secondly re-check that the variable hasn't changed after enqueing, that prevents the issue that the lock has been released and already re-acquired by the time the woken up backend checks for the lock's state. Reported-By: Jeff Janes Analyzed-By: Heikki Linnakangas Reviewed-By: Heikki Linnakangas Discussion: 5592DB35.2060401@iki.fi Backpatch: 9.5, where the lwlock scalability went in