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2015-11-16Message improvementsPeter Eisentraut
2015-11-16Speed up ruleutils' name de-duplication code, and fix overlength-name case.Tom Lane
Since commit 11e131854f8231a21613f834c40fe9d046926387, ruleutils.c has attempted to ensure that each RTE in a query or plan tree has a unique alias name. However, the code that was added for this could be quite slow, even as bad as O(N^3) if N identical RTE names must be replaced, as noted by Jeff Janes. Improve matters by building a transient hash table within set_rtable_names. The hash table in itself reduces the cost of detecting a duplicate from O(N) to O(1), and we can save another factor of N by storing the number of de-duplicated names already created for each entry, so that we don't have to re-try names already created. This way is probably a bit slower overall for small range tables, but almost by definition, such cases should not be a performance problem. In principle the same problem applies to the column-name-de-duplication code; but in practice that seems to be less of a problem, first because N is limited since we don't support extremely wide tables, and second because duplicate column names within an RTE are fairly rare, so that in practice the cost is more like O(N^2) not O(N^3). It would be very much messier to fix the column-name code, so for now I've left that alone. An independent problem in the same area was that the de-duplication code paid no attention to the identifier length limit, and would happily produce identifiers that were longer than NAMEDATALEN and wouldn't be unique after truncation to NAMEDATALEN. This could result in dump/reload failures, or perhaps even views that silently behaved differently than before. We can fix that by shortening the base name as needed. Fix it for both the relation and column name cases. In passing, check for interrupts in set_rtable_names, just in case it's still slow enough to be an issue. Back-patch to 9.3 where this code was introduced.
2015-11-15Fix ruleutils.c's dumping of whole-row Vars in ROW() and VALUES() contexts.Tom Lane
Normally ruleutils prints a whole-row Var as "foo.*". We already knew that that doesn't work at top level of a SELECT list, because the parser would treat the "*" as a directive to expand the reference into separate columns, not a whole-row Var. However, Joshua Yanovski points out in bug #13776 that the same thing happens at top level of a ROW() construct; and some nosing around in the parser shows that the same is true in VALUES(). Hence, apply the same workaround already devised for the SELECT-list case, namely to add a forced cast to the appropriate rowtype in these cases. (The alternative of just printing "foo" was rejected because it is difficult to avoid ambiguity against plain columns named "foo".) Back-patch to all supported branches.
2015-11-14pg_upgrade: properly detect file copy failure on WindowsBruce Momjian
Previously, file copy failures were ignored on Windows due to an incorrect return value check. Report by Manu Joye Backpatch through 9.1
2015-11-12vacuumdb: don't prompt for passwords over and overAlvaro Herrera
Having the script prompt for passwords over and over was a preexisting problem when it processed multiple databases or when it processed multiple analyze stages, but the parallel mode introduced in commit a179232047 made it worse. Fix the annoyance by keeping a copy of the password used by the first connection that requires one. Since users can (currently) only have a single password, there's no need for more complex arrangements (such as remembering one password per database). Per bug #13741 reported by Eric Brown. Patch authored and cross-reviewed by Haribabu Kommi and Michael Paquier, slightly tweaked by Álvaro Herrera. Discussion: http://www.postgresql.org/message-id/20151027193919.931.54948@wrigleys.postgresql.org Backpatch to 9.5, where parallel vacuumdb was introduced.
2015-11-12Fix unwanted flushing of libpq's input buffer when socket EOF is seen.Tom Lane
In commit 210eb9b743c0645d I centralized libpq's logic for closing down the backend communication socket, and made the new pqDropConnection routine always reset the I/O buffers to empty. Many of the call sites previously had not had such code, and while that amounted to an oversight in some cases, there was one place where it was intentional and necessary *not* to flush the input buffer: pqReadData should never cause that to happen, since we probably still want to process whatever data we read. This is the true cause of the problem Robert was attempting to fix in c3e7c24a1d60dc6a, namely that libpq no longer reported the backend's final ERROR message before reporting "server closed the connection unexpectedly". But that only accidentally fixed it, by invoking parseInput before the input buffer got flushed; and very likely there are timing scenarios where we'd still lose the message before processing it. To fix, pass a flag to pqDropConnection to tell it whether to flush the input buffer or not. On review I think flushing is actually correct for every other call site. Back-patch to 9.3 where the problem was introduced. In HEAD, also improve the comments added by c3e7c24a1d60dc6a.
2015-11-09Stamp 9.5beta2.REL9_5_BETA2Robert Haas
2015-11-09Translation updatesPeter Eisentraut
Source-Git-URL: git://git.postgresql.org/git/pgtranslation/messages.git Source-Git-Hash: cd263526676705b4a8a3a708c9842461c4a2bcc3
2015-11-09Set replication origin when decoding commit records.Andres Freund
By accident the replication origin was not set properly in DecodeCommit(). That's bad because the origin is passed to the output plugins origin filter, and accessible from the output plugin via ReorderBufferTXN->origin_id. Accessing the origin of individual changes worked before the fix, which is why this wasn't notices earlier. Reported-By: Craig Ringer Author: Craig Ringer Discussion: CAMsr+YFhBJLp=qfSz3-J+0P1zLkE8zNXM2otycn20QRMx380gw@mail.gmail.com Backpatch: 9.5, where replication origins where introduced
2015-11-08Fix 9.5 version of previous commit to match its log message.Noah Misch
2015-11-08Don't connect() to a wildcard address in test_postmaster_connection().Noah Misch
At least OpenBSD, NetBSD, and Windows don't support it. This repairs pg_ctl for listen_addresses='0.0.0.0' and listen_addresses='::'. Since pg_ctl prefers to test a Unix-domain socket, Windows users are most likely to need this change. Back-patch to 9.1 (all supported versions). This could change pg_ctl interaction with loopback-interface firewall rules. Therefore, in 9.4 and earlier (released branches), activate the change only on known-affected platforms. Reported (bug #13611) and designed by Kondo Yuta.
2015-11-07Rename PQsslAttributes() to PQsslAttributeNames(), and const-ify fully.Tom Lane
Per discussion, the original name was a bit misleading, and PQsslAttributeNames() seems more apropos. It's not quite too late to change this in 9.5, so let's change it while we can. Also, make sure that the pointer array is const, not only the pointed-to strings. Minor documentation wordsmithing while at it. Lars Kanis, slight adjustments by me
2015-11-07Fix enforcement of restrictions inside regexp lookaround constraints.Tom Lane
Lookahead and lookbehind constraints aren't allowed to contain backrefs, and parentheses within them are always considered non-capturing. Or so says the manual. But the regexp parser forgot about these rules once inside a parenthesized subexpression, so that constructs like (\w)(?=(\1)) were accepted (but then not correctly executed --- a case like this acted like (\w)(?=\w), without any enforcement that the two \w's match the same text). And in (?=((foo))) the innermost parentheses would be counted as capturing parentheses, though no text would ever be captured for them. To fix, properly pass down the "type" argument to the recursive invocation of parse(). Back-patch to all supported branches; it was agreed that silent misexecution of such patterns is worse than throwing an error, even though new errors in minor releases are generally not desirable.
2015-11-06Set include_realm=1 default in parse_hba_lineStephen Frost
With include_realm=1 being set down in parse_hba_auth_opt, if multiple options are passed on the pg_hba line, such as: host all all 0.0.0.0/0 gss include_realm=0 krb_realm=XYZ.COM We would mistakenly reset include_realm back to 1. Instead, we need to set include_realm=1 up in parse_hba_line, prior to parsing any of the additional options. Discovered by Jeff McCormick during testing. Bug introduced by 9a08841. Back-patch to 9.5
2015-11-05Fix erroneous hash calculations in gin_extract_jsonb_path().Tom Lane
The jsonb_path_ops code calculated hash values inconsistently in some cases involving nested arrays and objects. This would result in queries possibly not finding entries that they should find, when using a jsonb_path_ops GIN index for the search. The problem cases involve JSONB values that contain both scalars and sub-objects at the same nesting level, for example an array containing both scalars and sub-arrays. To fix, reset the current stack->hash after processing each value or sub-object, not before; and don't try to be cute about the outermost level's initial hash. Correcting this means that existing jsonb_path_ops indexes may now be inconsistent with the new hash calculation code. The symptom is the same --- searches not finding entries they should find --- but the specific rows affected are likely to be different. Users will need to REINDEX jsonb_path_ops indexes to make sure that all searches work as expected. Per bug #13756 from Daniel Cheng. Back-patch to 9.4 where the faulty logic was introduced.
2015-11-05Pass extra data to bgworkers, and use this to fix parallel contexts.Robert Haas
Up until now, the total amount of data that could be passed to a background worker at startup was one datum, which can be a small as 4 bytes on some systems. That's enough to pass a dsm_handle or an array index, but not much else. Add a bgw_extra flag to the BackgroundWorker struct, allowing up to 128 bytes to be passed to a new worker on any platform. Use this to fix a problem I recently discovered with the parallel context machinery added in 9.5: the master assigns each worker an array index, and each worker subsequently assigns itself an array index, and there's nothing to guarantee that the two sets of indexes match, leading to chaos. Normally, I would not back-patch the change to add bgw_extra, since it is basically a feature addition. However, since 9.5 is still in beta and there seems to be no other sensible way to repair the broken parallel context machinery, back-patch to 9.5. Existing background worker code can ignore the bgw_extra field without a problem, but might need to be recompiled since the structure size has changed. Report and patch by me. Review by Amit Kapila.
2015-11-03Improve comments about abbreviation abort.Robert Haas
Peter Geoghegan
2015-11-03Code + docs review for unicode linestyle patch.Tom Lane
Fix some brain fade in commit a2dabf0e1dda93c8: erroneous variable names in docs, rearrangements that made sentences less clear not more so, undocumented and poorly-chosen-anyway API behaviors of subroutines, bad grammar in error messages, copy-and-paste faults. Albe Laurenz and Tom Lane
2015-11-03shm_mq: Third attempt at fixing nowait behavior in shm_mq_receive.Robert Haas
Commit a1480ec1d3bacb9acb08ec09f22bc25bc033115b purported to fix the problems with commit b2ccb5f4e6c81305386edb34daf7d1d1e1ee112a, but it didn't completely fix them. The problem is that the checks were performed in the wrong order, leading to a race condition. If the sender attached, sent a message, and detached after the receiver called shm_mq_get_sender and before the receiver called shm_mq_counterparty_gone, we'd incorrectly return SHM_MQ_DETACHED before all messages were read. Repair by reversing the order of operations, and add a long comment explaining why this new logic is (hopefully) correct.
2015-10-31Fix serialization anomalies due to race conditions on INSERT.Kevin Grittner
On insert the CheckForSerializableConflictIn() test was performed before the page(s) which were going to be modified had been locked (with an exclusive buffer content lock). If another process acquired a relation SIReadLock on the heap and scanned to a page on which an insert was going to occur before the page was so locked, a rw-conflict would be missed, which could allow a serialization anomaly to be missed. The window between the check and the page lock was small, so the bug was generally not noticed unless there was high concurrency with multiple processes inserting into the same table. This was reported by Peter Bailis as bug #11732, by Sean Chittenden as bug #13667, and by others. The race condition was eliminated in heap_insert() by moving the check down below the acquisition of the buffer lock, which had been the very next statement. Because of the loop locking and unlocking multiple buffers in heap_multi_insert() a check was added after all inserts were completed. The check before the start of the inserts was left because it might avoid a large amount of work to detect a serialization anomaly before performing the all of the inserts and the related WAL logging. While investigating this bug, other SSI bugs which were even harder to hit in practice were noticed and fixed, an unnecessary check (covered by another check, so redundant) was removed from heap_update(), and comments were improved. Back-patch to all supported branches. Kevin Grittner and Thomas Munro
2015-10-30Fix typo in bgworker.cRobert Haas
2015-10-28Message style improvementsPeter Eisentraut
Message style, plurals, quoting, spelling, consistency with similar messages
2015-10-28Add missing serial comma, for consistency.Robert Haas
Amit Langote, per Etsuro Fujita
2015-10-28Fix incorrect message in ATWrongRelkindError.Robert Haas
Mistake introduced by commit 3bf3ab8c563699138be02f9dc305b7b77a724307. Etsuro Fujita
2015-10-27Fix secondary expected output for commit_ts testAlvaro Herrera
Per red wall in buildfarm
2015-10-27Fix BRIN free space computationsAlvaro Herrera
A bug in the original free space computation made it possible to return a page which wasn't actually able to fit the item. Since the insertion code isn't prepared to deal with PageAddItem failing, a PANIC resulted ("failed to add BRIN tuple [to new page]"). Add a macro to encapsulate the correct computation, and use it in brin_getinsertbuffer's callers before calling that routine, to raise an early error. I became aware of the possiblity of a problem in this area while working on ccc4c074994d734. There's no archived discussion about it, but it's easy to reproduce a problem in the unpatched code with something like CREATE TABLE t (a text); CREATE INDEX ti ON t USING brin (a) WITH (pages_per_range=1); for length in `seq 8000 8196` do psql -f - <<EOF TRUNCATE TABLE t; INSERT INTO t VALUES ('z'), (repeat('a', $length)); EOF done Backpatch to 9.5, where BRIN was introduced.
2015-10-27Cleanup commit timestamp module activaction, againAlvaro Herrera
Further tweak commit_ts.c so that on a standby the state is completely consistent with what that in the master, rather than behaving differently in the cases that the settings differ. Now in standby and master the module should always be active or inactive in lockstep. Author: Petr Jelínek, with some further tweaks by Álvaro Herrera. Backpatch to 9.5, where commit timestamps were introduced. Discussion: http://www.postgresql.org/message-id/5622BF9D.2010409@2ndquadrant.com
2015-10-27Measure string lengths only onceAlvaro Herrera
Bernd Helmle complained that CreateReplicationSlot() was assigning the same value to the same variable twice, so we could remove one of them. Code inspection reveals that we can actually remove both assignments: according to the author the assignment was there for beauty of the strlen line only, and another possible fix to that is to put the strlen in its own line, so do that. To be consistent within the file, refactor all duplicated strlen() calls, which is what we do elsewhere in the backend anyway. In basebackup.c, snprintf already returns the right length; no need for strlen afterwards. Backpatch to 9.4, where replication slots were introduced, to keep code identical. Some of this is older, but the patch doesn't apply cleanly and it's only of cosmetic value anyway. Discussion: http://www.postgresql.org/message-id/BE2FD71DEA35A2287EA5F018@eje.credativ.lan
2015-10-22shm_mq: Repair breakage from previous commit.Robert Haas
If the counterparty writes some data into the queue and then detaches, it's wrong to return SHM_MQ_DETACHED right away. If we do that, we fail to read whatever was written.
2015-10-22Add two missing cases to ATWrongRelkindError.Robert Haas
This way, we produce a better error message if someone tries to do something like ALTER INDEX .. ALTER COLUMN .. SET STORAGE. Amit Langote
2015-10-22shm_mq: Fix failure to notice a dead counterparty when nowait is used.Robert Haas
The shm_mq mechanism was intended to optionally notice when the process on the other end of the queue fails to attach to the queue. It does this by allowing the user to pass a BackgroundWorkerHandle; if the background worker in question is launched and dies without attaching to the queue, then we know it never will. This logic works OK in blocking mode, but when called with nowait = true we fail to notice that this has happened due to an asymmetry in the logic. Repair. Reported off-list by Rushabh Lathia. Patch by me.
2015-10-20Fix incorrect translation of minus-infinity datetimes for json/jsonb.Tom Lane
Commit bda76c1c8cfb1d11751ba6be88f0242850481733 caused both plus and minus infinity to be rendered as "infinity", which is not only wrong but inconsistent with the pre-9.4 behavior of to_json(). Fix that by duplicating the coding in date_out/timestamp_out/timestamptz_out more closely. Per bug #13687 from Stepan Perlov. Back-patch to 9.4, like the previous commit. In passing, also re-pgindent json.c, since it had gotten a bit messed up by recent patches (and I was already annoyed by indentation-related problems in back-patching this fix ...)
2015-10-20Fix incorrect comment in plannodes.hRobert Haas
Etsuro Fujita
2015-10-20Put back ssl_renegotiation_limit parameter, but only allow 0.Robert Haas
Per a report from Shay Rojansky, Npgsql sends ssl_renegotiation_limit=0 in the startup packet because it does not support renegotiation; other clients which have not attempted to support renegotiation might well behave similarly. The recent removal of this parameter forces them to break compatibility with either current PostgreSQL versions, or previous ones. Per discussion, the best solution is to accept the parameter but only allow a value of 0. Shay Rojansky, edited a little by me.
2015-10-20Fix back-patch of commit 8e3b4d9d40244c037bbc6e182ea3fabb9347d482.Noah Misch
master emits an extra context message compared to 9.5 and earlier.
2015-10-20Eschew "RESET statement_timeout" in tests.Noah Misch
Instead, use transaction abort. Given an unlucky bout of latency, the timeout would cancel the RESET itself. Buildfarm members gharial, lapwing, mereswine, shearwater, and sungazer witness that. Back-patch to 9.1 (all supported versions). The query_canceled test still could timeout before entering its subtransaction; for whatever reason, that has yet to happen on the buildfarm.
2015-10-19Fix incorrect handling of lookahead constraints in pg_regprefix().Tom Lane
pg_regprefix was doing nothing with lookahead constraints, which would be fine if it were the right kind of nothing, but it isn't: we have to terminate our search for a fixed prefix, not just pretend the LACON arc isn't there. Otherwise, if the current state has both a LACON outarc and a single plain-color outarc, we'd falsely conclude that the color represents an addition to the fixed prefix, and generate an extracted index condition that restricts the indexscan too much. (See added regression test case.) Terminating the search is conservative: we could traverse the LACON arc (thus assuming that the constraint can be satisfied at runtime) and then examine the outarcs of the linked-to state. But that would be a lot more work than it seems worth, because writing a LACON followed by a single plain character is a pretty silly thing to do. This makes a difference only in rather contrived cases, but it's a bug, so back-patch to all supported branches.
2015-10-18Fix order of arguments in ecpg generated typedef command.Michael Meskes
2015-10-16Miscellaneous cleanup of regular-expression compiler.Tom Lane
Revert our previous addition of "all" flags to copyins() and copyouts(); they're no longer needed, and were never anything but an unsightly hack. Improve a couple of infelicities in the REG_DEBUG code for dumping the NFA data structure, including adding code to count the total number of states and arcs. Add a couple of missed error checks. Add some more documentation in the README file, and some regression tests illustrating cases that exceeded the state-count limit and/or took unreasonable amounts of time before this set of patches. Back-patch to all supported branches.
2015-10-16Improve memory-usage accounting in regular-expression compiler.Tom Lane
This code previously counted the number of NFA states it created, and complained if a limit was exceeded, so as to prevent bizarre regex patterns from consuming unreasonable time or memory. That's fine as far as it went, but the code paid no attention to how many arcs linked those states. Since regexes can be contrived that have O(N) states but will need O(N^2) arcs after fixempties() processing, it was still possible to blow out memory, and take a long time doing it too. To fix, modify the bookkeeping to count space used by both states and arcs. I did not bother with including the "color map" in the accounting; it can only grow to a few megabytes, which is not a lot in comparison to what we're allowing for states+arcs (about 150MB on 64-bit machines or half that on 32-bit machines). Looking at some of the larger real-world regexes captured in the Tcl regression test suite suggests that the most that is likely to be needed for regexes found in the wild is under 10MB, so I believe that the current limit has enough headroom to make it okay to keep it as a hard-wired limit. In connection with this, redefine REG_ETOOBIG as meaning "regular expression is too complex"; the previous wording of "nfa has too many states" was already somewhat inapropos because of the error code's use for stack depth overrun, and it was not very user-friendly either. Back-patch to all supported branches.
2015-10-16Improve performance of pullback/pushfwd in regular-expression compiler.Tom Lane
The previous coding would create a new intermediate state every time it wanted to interchange the ordering of two constraint arcs. Certain regex features such as \Y can generate large numbers of parallel constraint arcs, and if we needed to reorder the results of that, we created unreasonable numbers of intermediate states. To improve matters, keep a list of already-created intermediate states associated with the state currently being considered by the outer loop; we can re-use such states to place all the new arcs leading to the same destination or source. I also took the trouble to redefine push() and pull() to have a less risky API: they no longer delete any state or arc that the caller might possibly have a pointer to, except for the specifically-passed constraint arc. This reduces the risk of re-introducing the same type of error seen in the failed patch for CVE-2007-4772. Back-patch to all supported branches.
2015-10-16Improve performance of fixempties() pass in regular-expression compiler.Tom Lane
The previous coding took something like O(N^4) time to fully process a chain of N EMPTY arcs. We can't really do much better than O(N^2) because we have to insert about that many arcs, but we can do lots better than what's there now. The win comes partly from using mergeins() to amortize de-duplication of arcs across multiple source states, and partly from exploiting knowledge of the ordering of arcs for each state to avoid looking at arcs we don't need to consider during the scan. We do have to be a bit careful of the possible reordering of arcs introduced by the sort-merge coding of the previous commit, but that's not hard to deal with. Back-patch to all supported branches.
2015-10-16Fix O(N^2) performance problems in regular-expression compiler.Tom Lane
Change the singly-linked in-arc and out-arc lists to be doubly-linked, so that arc deletion is constant time rather than having worst-case time proportional to the number of other arcs on the connected states. Modify the bulk arc transfer operations copyins(), copyouts(), moveins(), moveouts() so that they use a sort-and-merge algorithm whenever there's more than a small number of arcs to be copied or moved. The previous method is O(N^2) in the number of arcs involved, because it performs duplicate checking independently for each copied arc. The new method may change the ordering of existing arcs for the destination state, but nothing really cares about that. Provide another bulk arc copying method mergeins(), which is unused as of this commit but is needed for the next one. It basically is like copyins(), but the source arcs might not all come from the same state. Replace the O(N^2) bubble-sort algorithm used in carcsort() with a qsort() call. These changes greatly improve the performance of regex compilation for large or complex regexes, at the cost of extra space for arc storage during compilation. The original tradeoff was probably fine when it was made, but now we care more about speed and less about memory consumption. Back-patch to all supported branches.
2015-10-16Fix regular-expression compiler to handle loops of constraint arcs.Tom Lane
It's possible to construct regular expressions that contain loops of constraint arcs (that is, ^ $ AHEAD BEHIND or LACON arcs). There's no use in fully traversing such a loop at execution, since you'd just end up in the same NFA state without having consumed any input. Worse, such a loop leads to infinite looping in the pullback/pushfwd stage of compilation, because we keep pushing or pulling the same constraints around the loop in a vain attempt to move them to the pre or post state. Such looping was previously recognized in CVE-2007-4772; but the fix only handled the case of trivial single-state loops (that is, a constraint arc leading back to its source state) ... and not only that, it was incorrect even for that case, because it broke the admittedly-not-very-clearly-stated API contract of the pull() and push() subroutines. The first two regression test cases added by this commit exhibit patterns that result in assertion failures because of that (though there seem to be no ill effects in non-assert builds). The other new test cases exhibit multi-state constraint loops; in an unpatched build they will run until the NFA state-count limit is exceeded. To fix, remove the code added for CVE-2007-4772, and instead create a general-purpose constraint-loop-breaking phase of regex compilation that executes before we do pullback/pushfwd. Since we never need to traverse a constraint loop fully, we can just break the loop at any chosen spot, if we add clone states that can replicate any sequence of arc transitions that would've traversed just part of the loop. Also add some commentary clarifying why we have to have all these machinations in the first place. This class of problems has been known for some time --- we had a report from Marc Mamin about two years ago, for example, and there are related complaints in the Tcl bug tracker. I had discussed a fix of this kind off-list with Henry Spencer, but didn't get around to doing something about it until the issue was rediscovered by Greg Stark recently. Back-patch to all supported branches.
2015-10-16Remove cautions about using volatile from spin.h.Robert Haas
Commit 0709b7ee72e4bc71ad07b7120acd117265ab51d0 obsoleted this comment but neglected to update it. Thomas Munro
2015-10-16Fix a problem with parallel workers being unable to restore role.Robert Haas
check_role() tries to verify that the user has permission to become the requested role, but this is inappropriate in a parallel worker, which needs to exactly recreate the master's authorization settings. So skip the check in that case. This fixes a bug in commit 924bcf4f16d54c55310b28f77686608684734f42.
2015-10-16Invalidate caches after cranking up a parallel worker transaction.Robert Haas
Starting a parallel worker transaction changes our notion of which XIDs are in-progress or committed, and our notion of the current command counter ID. Therefore, our view of these caches prior to starting this transaction may no longer valid. Defend against that by clearing them. This fixes a bug in commit 924bcf4f16d54c55310b28f77686608684734f42.
2015-10-16Tighten up application of parallel mode checks.Robert Haas
Commit 924bcf4f16d54c55310b28f77686608684734f42 failed to enforce parallel mode checks during the commit of a parallel worker, because we exited parallel mode prior to ending the transaction so that we could pop the active snapshot. Re-establish parallel mode during parallel worker commit. Without this, it's far too easy for unsafe actions during the pre-commit sequence to crash the server instead of hitting the error checks as intended. Just to be extra paranoid, adjust a couple of the sanity checks in xact.c to check not only IsInParallelMode() but also IsParallelWorker().
2015-10-16Transfer current command counter ID to parallel workers.Robert Haas
Commit 924bcf4f16d54c55310b28f77686608684734f42 correctly forbade parallel workers to modify the command counter while in parallel mode, but it inexplicably neglected to actually transfer the current command counter from leader to workers. This can result in the workers seeing a different set of tuples from the leader, which is bad. Repair.
2015-10-16Don't send protocol messages to a shm_mq that no longer exists.Robert Haas
Commit 2bd9e412f92bc6a68f3e8bcb18e04955cc35001d introduced a mechanism for relaying protocol messages from a background worker to another backend via a shm_mq. However, there was no provision for shutting down the communication channel. Therefore, a protocol message sent late in the shutdown sequence, such as a DEBUG message resulting from cranking up log_min_messages, could crash the server. To fix, install an on_dsm_detach callback that disables sending messages to the shm_mq when the associated DSM is detached.