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* Fix locking a tuple updated by an aborted (sub)transactionAlvaro Herrera2016-09-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When heap_lock_tuple decides to follow the update chain, it tried to also lock any version of the tuple that was created by an update that was subsequently rolled back. This is pointless, since for all intents and purposes that tuple exists no more; and moreover it causes misbehavior, as reported independently by Marko Tiikkaja and Marti Raudsepp: some SELECT FOR UPDATE/SHARE queries may fail to return the tuples, and assertion-enabled builds crash. Fix by having heap_lock_updated_tuple test the xmin and return success immediately if the tuple was created by an aborted transaction. The condition where tuples become invisible occurs when an updated tuple chain is followed by heap_lock_updated_tuple, which reports the problem as HeapTupleSelfUpdated to its caller heap_lock_tuple, which in turn propagates that code outwards possibly leading the calling code (ExecLockRows) to believe that the tuple exists no longer. Backpatch to 9.3. Only on 9.5 and newer this leads to a visible failure, because of commit 27846f02c176; before that, heap_lock_tuple skips the whole dance when the tuple is already locked by the same transaction, because of the ancient HeapTupleSatisfiesUpdate behavior. Still, the buggy condition may also exist in more convoluted scenarios involving concurrent transactions, so it seems safer to fix the bug in the old branches too. Discussion: https://www.postgresql.org/message-id/CABRT9RC81YUf1=jsmWopcKJEro=VoeG2ou6sPwyOUTx_qteRsg@mail.gmail.com https://www.postgresql.org/message-id/48d3eade-98d3-8b9a-477e-1a8dc32a724d@joh.to
* Fix VACUUM_TRUNCATE_LOCK_WAIT_INTERVALSimon Riggs2016-09-09
| | | | | | | | | | lazy_truncate_heap() was waiting for VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL, but in microseconds not milliseconds as originally intended. Found by code inspection. Simon Riggs
* Fix mdtruncate() to close fd.c handle of deleted segments.Andres Freund2016-09-08
| | | | | | | | | | | | | | | | | mdtruncate() forgot to FileClose() a segment's mdfd_vfd, when deleting it. That lead to a fd.c handle to a truncated file being kept open until backend exit. The issue appears to have been introduced way back in 1a5c450f3024ac5, before that the handle was closed inside FileUnlink(). The impact of this bug is limited - only VACUUM and ON COMMIT TRUNCATE for temporary tables, truncate files in place (i.e. TRUNCATE itself is not affected), and the relation has to be bigger than 1GB. The consequences of a leaked fd.c handle aren't severe either. Discussion: <20160908220748.oqh37ukwqqncbl3n@alap3.anarazel.de> Backpatch: all supported releases
* Fix corrupt GIN_SEGMENT_ADDITEMS WAL records on big-endian hardware.Tom Lane2016-09-03
| | | | | | | | | | | | | | | | | | | | computeLeafRecompressWALData() tried to produce a uint16 WAL log field by memcpy'ing the first two bytes of an int-sized variable. That accidentally works on little-endian hardware, but not at all on big-endian. Replay then thinks it's looking at an ADDITEMS action with zero entries, and reads the first two bytes of the first TID therein as the next segno/action, typically leading to "unexpected GIN leaf action" errors during replay. Even if replay failed to crash, the resulting GIN index page would surely be incorrect. To fix, just declare the variable as uint16 instead. Per bug #14295 from Spencer Thomason (much thanks to Spencer for turning his problem into a self-contained test case). This likely also explains a previous report of the same symptom from Bernd Helmle. Back-patch to 9.4 where the problem was introduced (by commit 14d02f0bb). Discussion: <20160826072658.15676.7628@wrigleys.postgresql.org> Possible-Report: <2DA7350F7296B2A142272901@eje.land.credativ.lan>
* Don't require dynamic timezone abbreviations to match underlying time zone.Tom Lane2016-09-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, we threw an error if a dynamic timezone abbreviation did not match any abbreviation recorded in the referenced IANA time zone entry. That seemed like a good consistency check at the time, but it turns out that a number of the abbreviations in the IANA database are things that Olson and crew made up out of whole cloth. Their current policy is to remove such names in favor of using simple numeric offsets. Perhaps unsurprisingly, a lot of these made-up abbreviations have varied in meaning over time, which meant that our commit b2cbced9e and later changes made them into dynamic abbreviations. So with newer IANA database versions that don't mention these abbreviations at all, we fail, as reported in bug #14307 from Neil Anderson. It's worse than just a few unused-in-the-wild abbreviations not working, because the pg_timezone_abbrevs view stops working altogether (since its underlying function tries to compute the whole view result in one call). We considered deleting these abbreviations from our abbreviations list, but the problem with that is that we can't stay ahead of possible future IANA changes. Instead, let's leave the abbreviations list alone, and treat any "orphaned" dynamic abbreviation as just meaning the referenced time zone. It will behave a bit differently than it used to, in that you can't any longer override the zone's standard vs. daylight rule by using the "wrong" abbreviation of a pair, but that's better than failing entirely. (Also, this solution can be interpreted as adding a small new feature, which is that any abbreviation a user wants can be defined as referencing a time zone name.) Back-patch to all supported branches, since this problem affects all of them when using tzdata 2016f or newer. Report: <20160902031551.15674.67337@wrigleys.postgresql.org> Discussion: <6189.1472820913@sss.pgh.pa.us>
* Prevent starting a standalone backend with standby_mode on.Tom Lane2016-08-31
| | | | | | | | | | | | | | | | | | | This can't really work because standby_mode expects there to be more WAL arriving, which there will not ever be because there's no WAL receiver process to fetch it. Moreover, if standby_mode is on then hot standby might also be turned on, causing even more strangeness because that expects read-only sessions to be executing in parallel. Bernd Helmle reported a case where btree_xlog_delete_get_latestRemovedXid got confused, but rather than band-aiding individual problems it seems best to prevent getting anywhere near this state in the first place. Back-patch to all supported branches. In passing, also fix some omissions of errcodes in other ereport's in readRecoveryCommandFile(). Michael Paquier (errcode hacking by me) Discussion: <00F0B2CEF6D0CEF8A90119D4@eje.credativ.lan>
* Fix pg_xlogdump so that it handles cross-page XLP_FIRST_IS_CONTRECORD record.Fujii Masao2016-08-29
| | | | | | | | | | | | | | | | | | Previously pg_xlogdump failed to dump the contents of the WAL file if the file starts with the continuation WAL record which spans more than one pages. Since pg_xlogdump assumed that the continuation record always fits on a page, it could not find the valid WAL record to start reading from in that case. This patch changes pg_xlogdump so that it can handle a continuation WAL record which crosses a page boundary and find the valid record to start reading from. Back-patch to 9.3 where pg_xlogdump was introduced. Author: Pavan Deolasee Reviewed-By: Michael Paquier and Craig Ringer Discussion: CABOikdPsPByMiG6J01DKq6om2+BNkxHTPkOyqHM2a4oYwGKsqQ@mail.gmail.com
* Fix potential memory leakage from HandleParallelMessages().Tom Lane2016-08-26
| | | | | | | | | | | | | | | | HandleParallelMessages leaked memory into the caller's context. Since it's called from ProcessInterrupts, there is basically zero certainty as to what CurrentMemoryContext is, which means we could be leaking into long-lived contexts. Over the processing of many worker messages that would grow to be a problem. Things could be even worse than just a leak, if we happened to service the interrupt while ErrorContext is current: elog.c thinks it can reset that on its own whim, possibly yanking storage out from under HandleParallelMessages. Give HandleParallelMessages its own dedicated context instead, which we can reset during each call to ensure there's no accumulation of wasted memory. Discussion: <16610.1472222135@sss.pgh.pa.us>
* Fix assorted small bugs in ThrowErrorData().Tom Lane2016-08-26
| | | | | | | | | | | | | | | | | Copy the palloc'd strings into the correct context, ie ErrorContext not wherever the source ErrorData is. This would be a large bug, except that it appears that all catchers of thrown errors do either EmitErrorReport or CopyErrorData before doing anything that would cause transient memory contexts to be cleaned up. Still, it's wrong and it will bite somebody someday. Fix failure to copy cursorpos and internalpos. Utter the appropriate incantations involving recursion_depth, so that we'll behave sanely if we get an error inside pstrdup. (In general, the body of this function ought to act like, eg, errdetail().) Per code reading induced by Jakob Egger's report.
* Fix small query-lifespan memory leak in bulk updates.Tom Lane2016-08-24
| | | | | | | | | | | | | When there is an identifiable REPLICA IDENTITY index on the target table, heap_update leaks the id_attrs bitmapset. That's not many bytes, but it adds up over enough rows, since the code typically runs in a query-lifespan context. Bug introduced in commit e55704d8b, which did a rather poor job of cloning the existing use-pattern for RelationGetIndexAttrBitmap(). Per bug #14293 from Zhou Digoal. Back-patch to 9.4 where the bug was introduced. Report: <20160824114320.15676.45171@wrigleys.postgresql.org>
* Fix improper repetition of previous results from a hashed aggregate.Tom Lane2016-08-24
| | | | | | | | | | | | | | | | | | | | | | ExecReScanAgg's check for whether it could re-use a previously calculated hashtable neglected the possibility that the Agg node might reference PARAM_EXEC Params that are not referenced by its input plan node. That's okay if the Params are in upper tlist or qual expressions; but if one appears in aggregate input expressions, then the hashtable contents need to be recomputed when the Param's value changes. To avoid unnecessary performance degradation in the case of a Param that isn't within an aggregate input, add logic to the planner to determine which Params are within aggregate inputs. This requires a new field in struct Agg, but fortunately we never write plans to disk, so this isn't an initdb-forcing change. Per report from Jeevan Chalke. This has been broken since forever, so back-patch to all supported branches. Andrew Gierth, with minor adjustments by me Report: <CAM2+6=VY8ykfLT5Q8vb9B6EbeBk-NGuLbT6seaQ+Fq4zXvrDcA@mail.gmail.com>
* Fix possible sorting error when aborting use of abbreviated keys.Robert Haas2016-08-22
| | | | | | | | | | | | | | Due to an error in the abbreviated key abort logic, the most recently processed SortTuple could be incorrectly marked NULL, resulting in an incorrect final sort order. In the worst case, this could result in a corrupt btree index, which would need to be rebuild using REINDEX. However, abbrevation doesn't abort very often, not all data types use it, and only one tuple would end up in the wrong place, so the practical impact of this mistake may be somewhat limited. Report and patch by Peter Geoghegan.
* reorderbuffer: preserve errno while reporting errorAlvaro Herrera2016-08-19
| | | | | | | | | | | | Clobbering errno during cleanup after an error is an oft-repeated, easy to make mistake. Deal with it here as everywhere else, by saving it aside and restoring after cleanup, before ereport'ing. In passing, add a missing errcode declaration in another ereport() call in the same file, which I noticed while skimming the file looking for similar problems. Backpatch to 9.4, where this code was introduced.
* Fix deletion of speculatively inserted TOAST on conflictAndres Freund2016-08-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | INSERT .. ON CONFLICT runs a pre-check of the possible conflicting constraints before performing the actual speculative insertion. In case the inserted tuple included TOASTed columns the ON CONFLICT condition would be handled correctly in case the conflict was caught by the pre-check, but if two transactions entered the speculative insertion phase at the same time, one would have to re-try, and the code for aborting a speculative insertion did not handle deleting the speculatively inserted TOAST datums correctly. TOAST deletion would fail with "ERROR: attempted to delete invisible tuple" as we attempted to remove the TOAST tuples using simple_heap_delete which reasoned that the given tuples should not be visible to the command that wrote them. This commit updates the heap_abort_speculative() function which aborts the conflicting tuple to use itself, via toast_delete, for deleting associated TOAST datums. Like before, the inserted toast rows are not marked as being speculative. This commit also adds a isolationtester spec test, exercising the relevant code path. Unfortunately 9.5 cannot handle two waiting sessions, and thus cannot execute this test. Reported-By: Viren Negi, Oskari Saarenmaa Author: Oskari Saarenmaa, edited a bit by me Bug: #14150 Discussion: <20160519123338.12513.20271@wrigleys.postgresql.org> Backpatch: 9.5, where ON CONFLICT was introduced
* Properly re-initialize replication slot shared memory upon creation.Andres Freund2016-08-17
| | | | | | | | | | | | | | | | | | Slot creation did not clear all fields upon creation. After start the memory is zeroed, but when a physical replication slot was created in the shared memory of a previously existing logical slot, catalog_xmin would not be cleared. That in turn would prevent vacuum from doing its duties. To fix initialize all the fields. To make similar future bugs less likely, zero all of ReplicationSlotPersistentData, and re-order the rest of the initialization to be in struct member order. Analysis: Andrew Gierth Reported-By: md@chewy.com Author: Michael Paquier Discussion: <20160705173502.1398.70934@wrigleys.postgresql.org> Backpatch: 9.4, where replication slots were introduced
* Remove bogus dependencies on NUMERIC_MAX_PRECISION.Tom Lane2016-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NUMERIC_MAX_PRECISION is a purely arbitrary constraint on the precision and scale you can write in a numeric typmod. It might once have had something to do with the allowed range of a typmod-less numeric value, but at least since 9.1 we've allowed, and documented that we allowed, any value that would physically fit in the numeric storage format; which is something over 100000 decimal digits, not 1000. Hence, get rid of numeric_in()'s use of NUMERIC_MAX_PRECISION as a limit on the allowed range of the exponent in scientific-format input. That was especially silly in view of the fact that you can enter larger numbers as long as you don't use 'e' to do it. Just constrain the value enough to avoid localized overflow, and let make_result be the final arbiter of what is too large. Likewise adjust ecpg's equivalent of this code. Also get rid of numeric_recv()'s use of NUMERIC_MAX_PRECISION to limit the number of base-NBASE digits it would accept. That created a dump/restore hazard for binary COPY without doing anything useful; the wire-format limit on number of digits (65535) is about as tight as we would want. In HEAD, also get rid of pg_size_bytes()'s unnecessary intimacy with what the numeric range limit is. That code doesn't exist in the back branches. Per gripe from Aravind Kumar. Back-patch to all supported branches, since they all contain the documentation claim about allowed range of NUMERIC (cf commit cabf5d84b). Discussion: <2895.1471195721@sss.pgh.pa.us>
* Fix inappropriate printing of never-measured times in EXPLAIN.Tom Lane2016-08-12
| | | | | | | | | | | | | | | | | EXPLAIN (ANALYZE, TIMING OFF) would print an elapsed time of zero for a trigger function, because no measurement has been taken but it printed the field anyway. This isn't what EXPLAIN does elsewhere, so suppress it. In the same vein, EXPLAIN (ANALYZE, BUFFERS) with non-text output format would print buffer I/O timing numbers even when no measurement has been taken because track_io_timing is off. That seems not per policy, either, so change it. Back-patch to 9.2 where these features were introduced. Maksim Milyutin Discussion: <081c0540-ecaa-bd29-3fd2-6358f3b359a9@postgrespro.ru>
* Code cleanup in SyncRepWaitForLSN()Simon Riggs2016-08-12
| | | | | | | | | | Commit 14e8803f1 removed LWLocks when accessing MyProc->syncRepState but didn't clean up the surrounding code and comments. Cleanup and backpatch to 9.5, to keep code similar. Julien Rouhaud, improved by suggestion from Michael Paquier, implemented trivially by myself.
* Fix busted Assert for CREATE MATVIEW ... WITH NO DATA.Tom Lane2016-08-11
| | | | | | | | | | | | | | | | Commit 874fe3aea changed the command tag returned for CREATE MATVIEW/CREATE TABLE AS ... WITH NO DATA, but missed that there was code in spi.c that expected the command tag to always be "SELECT". Fortunately, the consequence was only an Assert failure, so this oversight should have no impact in production builds. Since this code path was evidently un-exercised, add a regression test. Per report from Shivam Saxena. Back-patch to 9.3, like the previous commit. Michael Paquier Report: <97218716-480B-4527-B5CD-D08D798A0C7B@dresources.com>
* Fix several one-byte buffer over-reads in to_numberPeter Eisentraut2016-08-08
| | | | | | | | | | | | | | | | | | | | | | | | | Several places in NUM_numpart_from_char(), which is called from the SQL function to_number(text, text), could accidentally read one byte past the end of the input buffer (which comes from the input text datum and is not null-terminated). 1. One leading space character would be skipped, but there was no check that the input was at least one byte long. This does not happen in practice, but for defensiveness, add a check anyway. 2. Commit 4a3a1e2cf apparently accidentally doubled that code that skips one space character (so that two spaces might be skipped), but there was no overflow check before skipping the second byte. Fix by removing that duplicate code. 3. A logic error would allow a one-byte over-read when looking for a trailing sign (S) placeholder. In each case, the extra byte cannot be read out directly, but looking at it might cause a crash. The third item was discovered by Piotr Stefaniak, the first two were found and analyzed by Tom Lane and Peter Eisentraut.
* Translation updatesPeter Eisentraut2016-08-08
| | | | | Source-Git-URL: git://git.postgresql.org/git/pgtranslation/messages.git Source-Git-Hash: f1a1631efd7a51f9b1122f22cf688a3124bf1342
* Fix two errors with nested CASE/WHEN constructs.Tom Lane2016-08-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ExecEvalCase() tried to save a cycle or two by passing &econtext->caseValue_isNull as the isNull argument to its sub-evaluation of the CASE value expression. If that subexpression itself contained a CASE, then *isNull was an alias for econtext->caseValue_isNull within the recursive call of ExecEvalCase(), leading to confusion about whether the inner call's caseValue was null or not. In the worst case this could lead to a core dump due to dereferencing a null pointer. Fix by not assigning to the global variable until control comes back from the subexpression. Also, avoid using the passed-in isNull pointer transiently for evaluation of WHEN expressions. (Either one of these changes would have been sufficient to fix the known misbehavior, but it's clear now that each of these choices was in itself dangerous coding practice and best avoided. There do not seem to be any similar hazards elsewhere in execQual.c.) Also, it was possible for inlining of a SQL function that implements the equality operator used for a CASE comparison to result in one CASE expression's CaseTestExpr node being inserted inside another CASE expression. This would certainly result in wrong answers since the improperly nested CaseTestExpr would be caused to return the inner CASE's comparison value not the outer's. If the CASE values were of different data types, a crash might result; moreover such situations could be abused to allow disclosure of portions of server memory. To fix, teach inline_function to check for "bare" CaseTestExpr nodes in the arguments of a function to be inlined, and avoid inlining if there are any. Heikki Linnakangas, Michael Paquier, Tom Lane Report: https://github.com/greenplum-db/gpdb/pull/327 Report: <4DDCEEB8.50602@enterprisedb.com> Security: CVE-2016-5423
* Fix misestimation of n_distinct for a nearly-unique column with many nulls.Tom Lane2016-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If ANALYZE found no repeated non-null entries in its sample, it set the column's stadistinct value to -1.0, intending to indicate that the entries are all distinct. But what this value actually means is that the number of distinct values is 100% of the table's rowcount, and thus it was overestimating the number of distinct values by however many nulls there are. This could lead to very poor selectivity estimates, as for example in a recent report from Andreas Joseph Krogh. We should discount the stadistinct value by whatever we've estimated the nulls fraction to be. (That is what will happen if we choose to use a negative stadistinct for a column that does have repeated entries, so this code path was just inconsistent.) In addition to fixing the stadistinct entries stored by several different ANALYZE code paths, adjust the logic where get_variable_numdistinct() forces an "all distinct" estimate on the basis of finding a relevant unique index. Unique indexes don't reject nulls, so there's no reason to assume that the null fraction doesn't apply. Back-patch to all supported branches. Back-patching is a bit of a judgment call, but this problem seems to affect only a few users (else we'd have identified it long ago), and it's bad enough when it does happen that destabilizing plan choices in a worse direction seems unlikely. Patch by me, with documentation wording suggested by Dean Rasheed Report: <VisenaEmail.26.df42f82acae38a58.156463942b8@tc7-visena> Discussion: <16143.1470350371@sss.pgh.pa.us>
* Don't propagate a null subtransaction snapshot up to parent transaction.Tom Lane2016-08-07
| | | | | | | | | This oversight could cause logical decoding to fail to decode an outer transaction containing changes, if a subtransaction had an XID but no actual changes. Per bug #14279 from Marko Tiikkaja. Patch by Marko based on analysis by Andrew Gierth. Discussion: <20160804191757.1430.39011@wrigleys.postgresql.org>
* In B-tree page deletion, clean up properly after page deletion failure.Tom Lane2016-08-06
| | | | | | | | | | | | | | | | | | | | | | In _bt_unlink_halfdead_page(), we might fail to find an immediate left sibling of the target page, perhaps because of corruption of the page sibling links. The code intends to cope with this by just abandoning the deletion attempt; but what actually happens is that it fails outright due to releasing the same buffer lock twice. (And error recovery masks a second problem, which is possible leakage of a pin on another page.) Seems to have been introduced by careless refactoring in commit efada2b8e. Since there are multiple cases to consider, let's make releasing the buffer lock in the failure case the responsibility of _bt_unlink_halfdead_page() not its caller. Also, avoid fetching the leaf page's left-link again after we've dropped lock on the page. This is probably harmless, but it's not exactly good coding practice. Per report from Kyotaro Horiguchi. Back-patch to 9.4 where the faulty code was introduced. Discussion: <20160803.173116.111915228.horiguchi.kyotaro@lab.ntt.co.jp>
* Fix bogus coding in WaitForBackgroundWorkerShutdown().Tom Lane2016-08-04
| | | | | | | | | | | | | | | | Some conditions resulted in "return" directly out of a PG_TRY block, which left the exception stack dangling, and to add insult to injury failed to restore the state of set_latch_on_sigusr1. This is a bug only in 9.5; in HEAD it was accidentally fixed by commit db0f6cad4, which removed the surrounding PG_TRY block. However, I (tgl) chose to apply the patch to HEAD as well, because the old coding was gratuitously different from WaitForBackgroundWorkerStartup(), and there would indeed have been no bug if it were done like that to start with. Dmitry Ivanov Discussion: <1637882.WfYN5gPf1A@abook>
* Remove duplicate InitPostmasterChild() call while starting a bgworker.Tom Lane2016-08-02
| | | | | | | | | | | This is apparently harmless on Windows, but on Unix it results in an assertion failure. We'd not noticed because this code doesn't get used on Unix unless you build with -DEXEC_BACKEND. Bug was evidently introduced by sloppy refactoring in commit 31c453165. Thomas Munro Discussion: <CAEepm=1VOnbVx4wsgQFvj94hu9jVt2nVabCr7QiooUSvPJXkgQ@mail.gmail.com>
* Block interrupts during HandleParallelMessages().Tom Lane2016-08-02
| | | | | | | | | | | | | | | | As noted by Alvaro, there are CHECK_FOR_INTERRUPTS() calls in the shm_mq.c functions called by HandleParallelMessages(). I believe they're all unreachable since we always pass nowait = true, but it doesn't seem like a great idea to assume that no such call will ever be reachable from HandleParallelMessages(). If that did happen, there would be a risk of a recursive call to HandleParallelMessages(), which it does not appear to be designed for --- for example, there's nothing that would prevent out-of-order processing of received messages. And certainly such cases cannot easily be tested. So let's prevent it by holding off interrupts for the duration of the function. Back-patch to 9.5 which contains identical code. Discussion: <14869.1470083848@sss.pgh.pa.us>
* Sync 9.5 version of access/transam/parallel.c with HEAD.Tom Lane2016-08-02
| | | | | | | | | This back-patches commit a5fe473ad (notably, marking ParallelMessagePending as volatile, which is not particularly optional). I also back-patched some previous cosmetic changes to remove unnecessary diffs between the two branches. I'm unsure how much of this code is actually reachable in 9.5, but to the extent that it is reachable, it needs to be maintained, and minimizing cross-branch diffs will make that easier.
* Don't CHECK_FOR_INTERRUPTS between WaitLatch and ResetLatch.Tom Lane2016-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | This coding pattern creates a race condition, because if an interesting interrupt happens after we've checked InterruptPending but before we reset our latch, the latch-setting done by the signal handler would get lost, and then we might block at WaitLatch in the next iteration without ever noticing the interrupt condition. You can put the CHECK_FOR_INTERRUPTS before WaitLatch or after ResetLatch, but not between them. Aside from fixing the bugs, add some explanatory comments to latch.h to perhaps forestall the next person from making the same mistake. In HEAD, also replace gather_readnext's direct call of HandleParallelMessages with CHECK_FOR_INTERRUPTS. It does not seem clean or useful for this one caller to bypass ProcessInterrupts and go straight to HandleParallelMessages; not least because that fails to consider the InterruptPending flag, resulting in useless work both here (if InterruptPending isn't set) and in the next CHECK_FOR_INTERRUPTS call (if it is). This thinko seems to have been introduced in the initial coding of storage/ipc/shm_mq.c (commit ec9037df2), and then blindly copied into all the subsequent parallel-query support logic. Back-patch relevant hunks to 9.4 to extirpate the error everywhere. Discussion: <1661.1469996911@sss.pgh.pa.us>
* Fix assorted fallout from IS [NOT] NULL patch.Tom Lane2016-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commits 4452000f3 et al established semantics for NullTest.argisrow that are a bit different from its initial conception: rather than being merely a cache of whether we've determined the input to have composite type, the flag now has the further meaning that we should apply field-by-field testing as per the standard's definition of IS [NOT] NULL. If argisrow is false and yet the input has composite type, the construct instead has the semantics of IS [NOT] DISTINCT FROM NULL. Update the comments in primnodes.h to clarify this, and fix ruleutils.c and deparse.c to print such cases correctly. In the case of ruleutils.c, this merely results in cosmetic changes in EXPLAIN output, since the case can't currently arise in stored rules. However, it represents a live bug for deparse.c, which would formerly have sent a remote query that had semantics different from the local behavior. (From the user's standpoint, this means that testing a remote nested-composite column for null-ness could have had unexpected recursive behavior much like that fixed in 4452000f3.) In a related but somewhat independent fix, make plancat.c set argisrow to false in all NullTest expressions constructed to represent "attnotnull" constructs. Since attnotnull is actually enforced as a simple null-value check, this is a more accurate representation of the semantics; we were previously overpromising what it meant for composite columns, which might possibly lead to incorrect planner optimizations. (It seems that what the SQL spec expects a NOT NULL constraint to mean is an IS NOT NULL test, so arguably we are violating the spec and should fix attnotnull to do the other thing. If we ever do, this part should get reverted.) Back-patch, same as the previous commit. Discussion: <10682.1469566308@sss.pgh.pa.us>
* Improve documentation about CREATE TABLE ... LIKE.Tom Lane2016-07-28
| | | | | | | | | | | | | The docs failed to explain that LIKE INCLUDING INDEXES would not preserve the names of indexes and associated constraints. Also, it wasn't mentioned that EXCLUDE constraints would be copied by this option. The latter oversight seems enough of a documentation bug to justify back-patching. In passing, do some minor copy-editing in the same area, and add an entry for LIKE under "Compatibility", since it's not exactly a faithful implementation of the standard's feature. Discussion: <20160728151154.AABE64016B@smtp.hushmail.com>
* Fix constant-folding of ROW(...) IS [NOT] NULL with composite fields.Tom Lane2016-07-26
| | | | | | | | | | | | | | | | | | | | | | | The SQL standard appears to specify that IS [NOT] NULL's tests of field nullness are non-recursive, ie, we shouldn't consider that a composite field with value ROW(NULL,NULL) is null for this purpose. ExecEvalNullTest got this right, but eval_const_expressions did not, leading to weird inconsistencies depending on whether the expression was such that the planner could apply constant folding. Also, adjust the docs to mention that IS [NOT] DISTINCT FROM NULL can be used as a substitute test if a simple null check is wanted for a rowtype argument. That motivated reordering things so that IS [NOT] DISTINCT FROM is described before IS [NOT] NULL. In HEAD, I went a bit further and added a table showing all the comparison-related predicates. Per bug #14235. Back-patch to all supported branches, since it's certainly undesirable that constant-folding should change the semantics. Report and patch by Andrew Gierth; assorted wordsmithing and revised regression test cases by me. Report: <20160708024746.1410.57282@wrigleys.postgresql.org>
* Remove very-obsolete estimates of shmem usage from postgresql.conf.sample.Tom Lane2016-07-19
| | | | | | | | | | runtime.sgml used to contain a table of estimated shared memory consumption rates for max_connections and some other GUCs. Commit 390bfc643 removed that on the well-founded grounds that (a) we weren't maintaining the entries well and (b) it no longer mattered so much once we got out from under SysV shmem limits. But it missed that there were even-more-obsolete versions of some of those numbers in comments in postgresql.conf.sample. Remove those too. Back-patch to 9.3 where the aforesaid commit went in.
* Fix crash in close_ps() for NaN input coordinates.Tom Lane2016-07-16
| | | | | | | | | | The Assert() here seems unreasonably optimistic. Andreas Seltenreich found that it could fail with NaNs in the input geometries, and it seems likely to me that it might fail in corner cases due to roundoff error, even for ordinary input values. As a band-aid, make the function return SQL NULL instead of crashing. Report: <87d1md1xji.fsf@credativ.de>
* Fix torn-page, unlogged xid and further risks from heap_update().Andres Freund2016-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When heap_update needs to look for a page for the new tuple version, because the current one doesn't have sufficient free space, or when columns have to be processed by the tuple toaster, it has to release the lock on the old page during that. Otherwise there'd be lock ordering and lock nesting issues. To avoid concurrent sessions from trying to update / delete / lock the tuple while the page's content lock is released, the tuple's xmax is set to the current session's xid. That unfortunately was done without any WAL logging, thereby violating the rule that no XIDs may appear on disk, without an according WAL record. If the database were to crash / fail over when the page level lock is released, and some activity lead to the page being written out to disk, the xid could end up being reused; potentially leading to the row becoming invisible. There might be additional risks by not having t_ctid point at the tuple itself, without having set the appropriate lock infomask fields. To fix, compute the appropriate xmax/infomask combination for locking the tuple, and perform WAL logging using the existing XLOG_HEAP_LOCK record. That allows the fix to be backpatched. This issue has existed for a long time. There appears to have been partial attempts at preventing dangers, but these never have fully been implemented, and were removed a long time ago, in 11919160 (cf. HEAP_XMAX_UNLOGGED). In master / 9.6, there's an additional issue, namely that the visibilitymap's freeze bit isn't reset at that point yet. Since that's a new issue, introduced only in a892234f830, that'll be fixed in a separate commit. Author: Masahiko Sawada and Andres Freund Reported-By: Different aspects by Thomas Munro, Noah Misch, and others Discussion: CAEepm=3fWAbWryVW9swHyLTY4sXVf0xbLvXqOwUoDiNCx9mBjQ@mail.gmail.com Backpatch: 9.1/all supported versions
* Make HEAP_LOCK/HEAP2_LOCK_UPDATED replay reset HEAP_XMAX_INVALID.Andres Freund2016-07-15
| | | | | | | | | | | | | | | 0ac5ad5 started to compress infomask bits in WAL records. Unfortunately the replay routines for XLOG_HEAP_LOCK/XLOG_HEAP2_LOCK_UPDATED forgot to reset the HEAP_XMAX_INVALID (and some other) hint bits. Luckily that's not problematic in the majority of cases, because after a crash/on a standby row locks aren't meaningful. Unfortunately that does not hold true in the presence of prepared transactions. This means that after a crash, or after promotion, row level locks held by a prepared, but not yet committed, prepared transaction might not be enforced. Discussion: 20160715192319.ubfuzim4zv3rqnxv@alap3.anarazel.de Backpatch: 9.3, the oldest branch on which 0ac5ad5 is present.
* Avoid serializability errors when locking a tuple with a committed updateAlvaro Herrera2016-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When key-share locking a tuple that has been not-key-updated, and the update is a committed transaction, in some cases we raised serializability errors: ERROR: could not serialize access due to concurrent update Because the key-share doesn't conflict with the update, the error is unnecessary and inconsistent with the case that the update hasn't committed yet. This causes problems for some usage patterns, even if it can be claimed that it's sufficient to retry the aborted transaction: given a steady stream of updating transactions and a long locking transaction, the long transaction can be starved indefinitely despite multiple retries. To fix, we recognize that HeapTupleSatisfiesUpdate can return HeapTupleUpdated when an updating transaction has committed, and that we need to deal with that case exactly as if it were a non-committed update: verify whether the two operations conflict, and if not, carry on normally. If they do conflict, however, there is a difference: in the HeapTupleBeingUpdated case we can just sleep until the concurrent transaction is gone, while in the HeapTupleUpdated case this is not possible and we must raise an error instead. Per trouble report from Olivier Dony. In addition to a couple of test cases that verify the changed behavior, I added a test case to verify the behavior that remains unchanged, namely that errors are raised when a update that modifies the key is used. That must still generate serializability errors. One pre-existing test case changes behavior; per discussion, the new behavior is actually the desired one. Discussion: https://www.postgresql.org/message-id/560AA479.4080807@odoo.com https://www.postgresql.org/message-id/20151014164844.3019.25750@wrigleys.postgresql.org Backpatch to 9.3, where the problem appeared.
* Fix GiST index build for NaN values in geometric types.Tom Lane2016-07-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GiST index build could go into an infinite loop when presented with boxes (or points, circles or polygons) containing NaN component values. This happened essentially because the code assumed that x == x is true for any "double" value x; but it's not true for NaNs. The looping behavior was not the only problem though: we also attempted to sort the items using simple double comparisons. Since NaNs violate the trichotomy law, qsort could (in principle at least) get arbitrarily confused and mess up the sorting of ordinary values as well as NaNs. And we based splitting choices on box size calculations that could produce NaNs, again resulting in undesirable behavior. To fix, replace all comparisons of doubles in this logic with float8_cmp_internal, which is NaN-aware and is careful to sort NaNs consistently, higher than any non-NaN. Also rearrange the box size calculation to not produce NaNs; instead it should produce an infinity for a box with NaN on one side and not-NaN on the other. I don't by any means claim that this solves all problems with NaNs in geometric values, but it should at least make GiST index insertion work reliably with such data. It's likely that the index search side of things still needs some work, and probably regular geometric operations too. But with this patch we're laying down a convention for how such cases ought to behave. Per bug #14238 from Guang-Dih Lei. Back-patch to 9.2; the code used before commit 7f3bd86843e5aad8 is quite different and doesn't lock up on my simple test case, nor on the submitter's dataset. Report: <20160708151747.1426.60150@wrigleys.postgresql.org> Discussion: <28685.1468246504@sss.pgh.pa.us>
* Fix failure to handle conflicts in non-arbiter exclusion constraints.Tom Lane2016-07-04
| | | | | | | | | | | | | | | | | | | ExecInsertIndexTuples treated an exclusion constraint as subject to noDupErr processing even when it was not listed in arbiterIndexes, and would therefore not error out for a conflict in such a constraint, instead returning it as an arbiter-index failure. That led to an infinite loop in ExecInsert, since ExecCheckIndexConstraints ignored the index as-intended and therefore didn't throw the expected error. To fix, make the exclusion constraint code path use the same condition as the index_insert call does to decide whether no-error-for-duplicates behavior is appropriate. While at it, refactor a little bit to avoid unnecessary list_member_oid calls. (That surely wouldn't save anything worth noticing, but I find the code a bit clearer this way.) Per bug report from Heikki Rauhala. Back-patch to 9.5 where ON CONFLICT was introduced. Report: <4C976D6B-76B4-434C-8052-D009F7B7AEDA@reaktor.fi>
* Be more paranoid in ruleutils.c's get_variable().Tom Lane2016-07-01
| | | | | | | | | | | | | | | | | | | We were merely Assert'ing that the Var matched the RTE it's supposedly from. But if the user passes incorrect information to pg_get_expr(), the RTE might in fact not match; this led either to Assert failures or core dumps, as reported by Chris Hanks in bug #14220. To fix, just convert the Asserts to test-and-elog. Adjust an existing test-and-elog elsewhere in the same function to be consistent in wording. (If we really felt these were user-facing errors, we might promote them to ereport's; but I can't convince myself that they're worth translating.) Back-patch to 9.3; the problematic code doesn't exist before that, and a quick check says that 9.2 doesn't crash on such cases. Michael Paquier and Thomas Munro Report: <20160629224349.1407.32667@wrigleys.postgresql.org>
* Fix crash bug in RestoreSnapshot.Robert Haas2016-07-01
| | | | | | | | | If serialized_snapshot->subxcnt > 0 and serialized_snapshot->xcnt == 0, the old coding would do the wrong thing and crash. This can happen on standby servers. Report by Andreas Seltenreich. Patch by Thomas Munro, reviewed by Amit Kapila and tested by Andreas Seltenreich.
* Fix typo in ReorderBufferIterTXNInit().Tom Lane2016-06-30
| | | | | | | | | | This looks like it would cause changes from subtransactions to be missed by the iterator being constructed, if those changes had been spilled to disk previously. This implies that large subtransactions might be lost (in whole or in part) by logical replication. Found and fixed by Petru-Florin Mihancea, per bug #14208. Report: <20160622144830.5791.22512@wrigleys.postgresql.org>
* Fix CREATE MATVIEW/CREATE TABLE AS ... WITH NO DATA to not plan the query.Tom Lane2016-06-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, these commands always planned the given query and went through executor startup before deciding not to actually run the query if WITH NO DATA is specified. This behavior is problematic for pg_dump because it may cause errors to be raised that we would rather not see before a REFRESH MATERIALIZED VIEW command is issued. See for example bug #13907 from Marian Krucina. This change is not sufficient to fix that particular bug, because we also need to tweak pg_dump to issue the REFRESH later, but it's a necessary step on the way. A user-visible side effect of doing things this way is that the returned command tag for WITH NO DATA cases will now be "CREATE MATERIALIZED VIEW" or "CREATE TABLE AS", not "SELECT 0". We could preserve the old behavior but it would take more code, and arguably that was just an implementation artifact not intended behavior anyhow. In 9.5 and HEAD, also get rid of the static variable CreateAsReladdr, which was trouble waiting to happen; there is not any prohibition on nested CREATE commands. Back-patch to 9.3 where CREATE MATERIALIZED VIEW was introduced. Michael Paquier and Tom Lane Report: <20160202161407.2778.24659@wrigleys.postgresql.org>
* Fix handling of multixacts predating pg_upgradeAlvaro Herrera2016-06-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After pg_upgrade, it is possible that some tuples' Xmax have multixacts corresponding to the old installation; such multixacts cannot have running members anymore. In many code sites we already know not to read them and clobber them silently, but at least when VACUUM tries to freeze a multixact or determine whether one needs freezing, there's an attempt to resolve it to its member transactions by calling GetMultiXactIdMembers, and if the multixact value is "in the future" with regards to the current valid multixact range, an error like this is raised: ERROR: MultiXactId 123 has not been created yet -- apparent wraparound and vacuuming fails. Per discussion with Andrew Gierth, it is completely bogus to try to resolve multixacts coming from before a pg_upgrade, regardless of where they stand with regards to the current valid multixact range. It's possible to get from under this problem by doing SELECT FOR UPDATE of the problem tuples, but if tables are large, this is slow and tedious, so a more thorough solution is desirable. To fix, we realize that multixacts in xmax created in 9.2 and previous have a specific bit pattern that is never used in 9.3 and later (we already knew this, per comments and infomask tests sprinkled in various places, but we weren't leveraging this knowledge appropriately). Whenever the infomask of the tuple matches that bit pattern, we just ignore the multixact completely as if Xmax wasn't set; or, in the case of tuple freezing, we act as if an unwanted value is set and clobber it without decoding. This guarantees that no errors will be raised, and that the values will be progressively removed until all tables are clean. Most callers of GetMultiXactIdMembers are patched to recognize directly that the value is a removable "empty" multixact and avoid calling GetMultiXactIdMembers altogether. To avoid changing the signature of GetMultiXactIdMembers() in back branches, we keep the "allow_old" boolean flag but rename it to "from_pgupgrade"; if the flag is true, we always return an empty set instead of looking up the multixact. (I suppose we could remove the argument in the master branch, but I chose not to do so in this commit). This was broken all along, but the error-facing message appeared first because of commit 8e9a16ab8f7f and was partially fixed in a25c2b7c4db3. This fix, backpatched all the way back to 9.3, goes approximately in the same direction as a25c2b7c4db3 but should cover all cases. Bug analysis by Andrew Gierth and Álvaro Herrera. A number of public reports match this bug: https://www.postgresql.org/message-id/20140330040029.GY4582@tamriel.snowman.net https://www.postgresql.org/message-id/538F3D70.6080902@publicrelay.com https://www.postgresql.org/message-id/556439CF.7070109@pscs.co.uk https://www.postgresql.org/message-id/SG2PR06MB0760098A111C88E31BD4D96FB3540@SG2PR06MB0760.apcprd06.prod.outlook.com https://www.postgresql.org/message-id/20160615203829.5798.4594@wrigleys.postgresql.org
* Fix building of large (bigger than shared_buffers) hash indexes.Tom Lane2016-06-24
| | | | | | | | | | | | | | | | When the index is predicted to need more than NBuffers buckets, CREATE INDEX attempts to sort the index entries by hash key before insertion, so as to reduce thrashing. This code path got broken by commit 9f03ca915196dfc8, which overlooked that _hash_form_tuple() is not just an alias for index_form_tuple(). The index got built anyway, but with garbage data, so that searches for pre-existing tuples always failed. Fix by refactoring to separate construction of the indexable data from calling index_form_tuple(). Per bug #14210 from Daniel Newman. Back-patch to 9.5 where the bug was introduced. Report: <20160623162507.17237.39471@wrigleys.postgresql.org>
* Make "postgres -C guc" print "" not "(null)" for null-valued GUCs.Tom Lane2016-06-22
| | | | | | | | | | | | | Commit 0b0baf262 et al made this case print "(null)" on the grounds that that's what happened on platforms that didn't crash. But neither behavior was actually intentional. What we should print is just an empty string, for compatibility with the behavior of SHOW and other ways of examining string GUCs. Those code paths don't distinguish NULL from empty strings, so we should not here either. Per gripe from Alain Radix. Like the previous patch, back-patch to 9.2 where -C option was introduced. Discussion: <CA+YdpwxPUADrmxSD7+Td=uOshMB1KkDN7G7cf+FGmNjjxMhjbw@mail.gmail.com>
* Finish up XLOG_HINT renamingAlvaro Herrera2016-06-17
| | | | | | | Commit b8fd1a09f3 renamed XLOG_HINT to XLOG_FPI, but neglected two places. Backpatch to 9.3, like that commit.
* Fix validation of overly-long IPv6 addresses.Tom Lane2016-06-16
| | | | | | | | | The inet/cidr types sometimes failed to reject IPv6 inputs with too many colon-separated fields, instead translating them to '::/0'. This is the result of a thinko in the original ISC code that seems to be as yet unreported elsewhere. Per bug #14198 from Stefan Kaltenbrunner. Report: <20160616182222.5798.959@wrigleys.postgresql.org>
* Avoid crash in "postgres -C guc" for a GUC with a null string value.Tom Lane2016-06-16
| | | | | | | | | | Emit "(null)" instead, which was the behavior all along on platforms that don't crash, eg OS X. Per report from Jehan-Guillaume de Rorthais. Back-patch to 9.2 where -C option was introduced. Michael Paquier Report: <20160615204036.2d35d86a@firost>