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2012-11-30Add missing buffer lock acquisition in GetTupleForTrigger().Tom Lane
If we had not been holding buffer pin continuously since the tuple was initially fetched by the UPDATE or DELETE query, it would be possible for VACUUM or a page-prune operation to move the tuple while we're trying to copy it. This would result in a garbage "old" tuple value being passed to an AFTER ROW UPDATE or AFTER ROW DELETE trigger. The preconditions for this are somewhat improbable, and the timing constraints are very tight; so it's not so surprising that this hasn't been reported from the field, even though the bug has been there a long time. Problem found by Andres Freund. Back-patch to all active branches.
2012-11-29Produce a more useful error message for over-length Unix socket paths.Tom Lane
The length of a socket path name is constrained by the size of struct sockaddr_un, and there's not a lot we can do about it since that is a kernel API. However, it would be a good thing if we produced an intelligible error message when the user specifies a socket path that's too long --- and getaddrinfo's standard API is too impoverished to do this in the natural way. So insert explicit tests at the places where we construct a socket path name. Now you'll get an error that makes sense and even tells you what the limit is, rather than something generic like "Non-recoverable failure in name resolution". Per trouble report from Jeremy Drake and a fix idea from Andrew Dunstan.
2012-11-29Fix assorted bugs in CREATE INDEX CONCURRENTLY.Tom Lane
This patch changes CREATE INDEX CONCURRENTLY so that the pg_index flag changes it makes without exclusive lock on the index are made via heap_inplace_update() rather than a normal transactional update. The latter is not very safe because moving the pg_index tuple could result in concurrent SnapshotNow scans finding it twice or not at all, thus possibly resulting in index corruption. In addition, fix various places in the code that ought to check to make sure that the indexes they are manipulating are valid and/or ready as appropriate. These represent bugs that have existed since 8.2, since a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid index behind, and we ought not try to do anything that might fail with such an index. Also fix RelationReloadIndexInfo to ensure it copies all the pg_index columns that are allowed to change after initial creation. Previously we could have been left with stale values of some fields in an index relcache entry. It's not clear whether this actually had any user-visible consequences, but it's at least a bug waiting to happen. This is a subset of a patch already applied in 9.2 and HEAD. Back-patch into all earlier supported branches. Tom Lane and Andres Freund
2012-11-29When processing nested structure pointer variables ecpg always expected anMichael Meskes
array datatype which of course is wrong. Applied patch by Muhammad Usama <m.usama@gmail.com> to fix this.
2012-11-22Fix pg_resetxlog to use correct path to postmaster.pid.Tom Lane
Since we've already chdir'd into the data directory, the file should be referenced as just "postmaster.pid", without prefixing the directory path. This is harmless in the normal case where an absolute PGDATA path is used, but quite dangerous if a relative path is specified, since the program might then fail to notice an active postmaster. Reported by Hari Babu. This got broken in my commit eb5949d190e80360386113fde0f05854f0c9824d, so patch all active versions.
2012-11-19Improve handling of INT_MIN / -1 and related cases.Tom Lane
Some platforms throw an exception for this division, rather than returning a necessarily-overflowed result. Since we were testing for overflow after the fact, an exception isn't nice. We can avoid the problem by treating division by -1 as negation. Add some regression tests so that we'll find out if any compilers try to optimize away the overflow check conditions. Back-patch of commit 1f7cb5c30983752ff8de833de30afcaee63536d0. Per discussion with Xi Wang, though this is different from the patch he submitted.
2012-11-18Limit values of archive_timeout, post_auth_delay, auth_delay.milliseconds.Tom Lane
The previous definitions of these GUC variables allowed them to range up to INT_MAX, but in point of fact the underlying code would suffer overflows or other errors with large values. Reduce the maximum values to something that won't misbehave. There's no apparent value in working harder than this, since very large delays aren't sensible for any of these. (Note: the risk with archive_timeout is that if we're late checking the state, the timestamp difference it's being compared to might overflow. So we need some amount of slop; the choice of INT_MAX/2 is arbitrary.) Per followup investigation of bug #7670. Although this isn't a very significant fix, might as well back-patch.
2012-11-14Fix the int8 and int2 cases of (minimum possible integer) % (-1).Tom Lane
The correct answer for this (or any other case with arg2 = -1) is zero, but some machines throw a floating-point exception instead of behaving sanely. Commit f9ac414c35ea084ff70c564ab2c32adb06d5296f dealt with this in int4mod, but overlooked the fact that it also happens in int8mod (at least on my Linux x86_64 machine). Protect int2mod as well; it's not clear whether any machines fail there (mine does not) but since the test is so cheap it seems better safe than sorry. While at it, simplify the original guard in int4mod: we need only check for arg2 == -1, we don't need to check arg1 explicitly. Xi Wang, with some editing by me.
2012-11-13Fix memory leaks in record_out() and record_send().Tom Lane
record_out() leaks memory: it fails to free the strings returned by the per-column output functions, and also is careless about detoasted values. This results in a query-lifespan memory leakage when returning composite values to the client, because printtup() runs the output functions in the query-lifespan memory context. Fix it to handle these issues the same way printtup() does. Also fix a similar leakage in record_send(). (At some point we might want to try to run output functions in shorter-lived memory contexts, so that we don't need a zero-leakage policy for them. But that would be a significantly more invasive patch, which doesn't seem like material for back-patching.) In passing, use appendStringInfoCharMacro instead of appendStringInfoChar in the innermost data-copying loop of record_out, to try to shave a few cycles from this function's runtime. Per trouble report from Carlos Henrique Reimer. Back-patch to all supported versions.
2012-11-11Check for stack overflow in transformSetOperationTree().Tom Lane
Since transformSetOperationTree() recurses, it can be driven to stack overflow with enough UNION/INTERSECT/EXCEPT clauses in a query. Add a check to ensure it fails cleanly instead of crashing. Per report from Matthew Gerber (though it's not clear whether this is the only thing going wrong for him). Historical note: I think the reasoning behind not putting a check here in the beginning was that the check in transformExpr() ought to be sufficient to guard the whole parser. However, because transformSetOperationTree() recurses all the way to the bottom of the set-operation tree before doing any analysis of the statement's expressions, that check doesn't save it.
2012-11-05Fix handling of inherited check constraints in ALTER COLUMN TYPE.Tom Lane
This case got broken in 8.4 by the addition of an error check that complains if ALTER TABLE ONLY is used on a table that has children. We do use ONLY for this situation, but it's okay because the necessary recursion occurs at a higher level. So we need to have a separate flag to suppress recursion without making the error check. Reported and patched by Pavan Deolasee, with some editorial adjustments by me. Back-patch to 8.4, since this is a regression of functionality that worked in earlier branches.
2012-10-26Prefer actual constants to pseudo-constants in equivalence class machinery.Tom Lane
generate_base_implied_equalities_const() should prefer plain Consts over other em_is_const eclass members when choosing the "pivot" value that all the other members will be equated to. This makes it more likely that the generated equalities will be useful in constraint-exclusion proofs. Per report from Rushabh Lathia.
2012-10-24Prevent parser from believing that views have system columns.Tom Lane
Views should not have any pg_attribute entries for system columns. However, we forgot to remove such entries when converting a table to a view. This could lead to crashes later on, if someone attempted to reference such a column, as reported by Kohei KaiGai. This problem is corrected properly in HEAD (by removing the pg_attribute entries during conversion), but in the back branches we need to defend against existing mis-converted views. This fix costs us an extra syscache lookup per system column reference, which is annoying but probably not really measurable in the big scheme of things.
2012-10-19Fix hash_search to avoid corruption of the hash table on out-of-memory.Tom Lane
An out-of-memory error during expand_table() on a palloc-based hash table would leave a partially-initialized entry in the table. This would not be harmful for transient hash tables, since they'd get thrown away anyway at transaction abort. But for long-lived hash tables, such as the relcache hash, this would effectively corrupt the table, leading to crash or other misbehavior later. To fix, rearrange the order of operations so that table enlargement is attempted before we insert a new entry, rather than after adding it to the hash table. Problem discovered by Hitoshi Harada, though this is a bit different from his proposed patch.
2012-10-19Fix ruleutils to print "INSERT INTO foo DEFAULT VALUES" correctly.Tom Lane
Per bug #7615 from Marko Tiikkaja. Apparently nobody ever tried this case before ...
2012-10-18Further tweaking of the readfile() function in pg_ctl.Heikki Linnakangas
Don't leak a file descriptor if the file is empty or we can't read its size. Expect there to be a newline at the end of the last line, too. If there isn't, ignore anything after the last newline. This makes it a tiny bit more robust in case the file is appended to concurrently, so that we don't return the last line if it hasn't been fully written yet. And this makes the code a bit less obscure, anyway. Per Tom Lane's suggestion. Backpatch to all supported branches.
2012-10-18Fix planning of non-strict equivalence clauses above outer joins.Tom Lane
If a potential equivalence clause references a variable from the nullable side of an outer join, the planner needs to take care that derived clauses are not pushed to below the outer join; else they may use the wrong value for the variable. (The problem arises only with non-strict clauses, since if an upper clause can be proven strict then the outer join will get simplified to a plain join.) The planner attempted to prevent this type of error by checking that potential equivalence clauses aren't outerjoin-delayed as a whole, but actually we have to check each side separately, since the two sides of the clause will get moved around separately if it's treated as an equivalence. Bugs of this type can be demonstrated as far back as 7.4, even though releases before 8.3 had only a very ad-hoc notion of equivalence clauses. In addition, we neglected to account for the possibility that such clauses might have nonempty nullable_relids even when not outerjoin-delayed; so the equivalence-class machinery lacked logic to compute correct nullable_relids values for clauses it constructs. This oversight was harmless before 9.2 because we were only using RestrictInfo.nullable_relids for OR clauses; but as of 9.2 it could result in pushing constructed equivalence clauses to incorrect places. (This accounts for bug #7604 from Bill MacArthur.) Fix the first problem by adding a new test check_equivalence_delay() in distribute_qual_to_rels, and fix the second one by adding code in equivclass.c and called functions to set correct nullable_relids for generated clauses. Although I believe the second part of this is not currently necessary before 9.2, I chose to back-patch it anyway, partly to keep the logic similar across branches and partly because it seems possible we might find other reasons why we need valid values of nullable_relids in the older branches. Add regression tests illustrating these problems. In 9.0 and up, also add test cases checking that we can push constants through outer joins, since we've broken that optimization before and I nearly broke it again with an overly simplistic patch for this problem.
2012-10-15Fix race condition in pg_ctl reading postmaster.pid.Heikki Linnakangas
If postmaster changed postmaster.pid while pg_ctl was reading it, pg_ctl could overrun the buffer it allocated for the file. Fix by reading the whole file to memory with one read() call. initdb contains an identical copy of the readfile() function, but the files that initdb reads are static, not modified concurrently. Nevertheless, add a simple bounds-check there, if only to silence static analysis tools. Per report from Dave Vitek. Backpatch to all supported branches.
2012-10-11Fix cross-type case in partial row matching for hashed subplans.Tom Lane
When hashing a subplan like "WHERE (a, b) NOT IN (SELECT x, y FROM ...)", findPartialMatch() attempted to match rows using the hashtable's internal equality operators, which of course are for x and y's datatypes. What we need to use are the potentially cross-type operators for a=x, b=y, etc. Failure to do that leads to wrong answers or even crashes. The scope for problems is limited to cases where we have different types with compatible hash functions (else we'd not be using a hashed subplan), but for example int4 vs int8 can cause the problem. Per bug #7597 from Bo Jensen. This has been wrong since the hashed-subplan code was written, so patch all the way back.
2012-10-09Fix PGXS support for building loadable modules on AIX.Tom Lane
Building a shlib on AIX requires use of the mkldexport.sh script, but we failed to install that, preventing its use from non-source-tree contexts. Also, Makefile.aix had the wrong idea about where to find the installed copy of the postgres.imp symbol file used by AIX. Per report from John Pierce. Patch all the way back, since this has been broken since the beginning of PGXS.
2012-10-08Fix lo_import and lo_export to return useful error messages more often.Tom Lane
I found that these functions tend to return -1 while leaving an empty error message string in the PGconn, if they suffer some kind of I/O error on the file. The reason is that lo_close, which thinks it's executed a perfectly fine SQL command, clears the errorMessage. The minimum-change workaround is to reorder operations here so that we don't fill the errorMessage until after lo_close.
2012-10-08Fix lo_export usage in example programs.Tom Lane
lo_export returns -1, not zero, on failure.
2012-10-03REASSIGN OWNED: consider grants on tablespaces, tooAlvaro Herrera
Apparently this was considered in the original code (see commit cec3b0a9) but I failed to notice that such entries would always be skipped by the database check at the start of the loop. Per bugs #7578 by Nikolay, #6116 by tushar.qa@gmail.com.
2012-10-02Fix access past end of string in date parsing.Heikki Linnakangas
This affects date_in(), and a couple of other funcions that use DecodeDate(). Hitoshi Harada
2012-09-29Fix bugs in "restore.sql" script emitted in pg_dump tar output.Tom Lane
The tar output module did some very ugly and ultimately incorrect hacking on COPY commands to try to get them to work in the context of restoring a deconstructed tar archive. In particular, it would fail altogether for table names containing any upper-case characters, since it smashed the command string to lower-case before modifying it (and, just to add insult to injury, did that in a way that would fail in multibyte encodings). I don't see any particular value in being flexible about the case of the command keywords, since the string will just have been created by dumpTableData, so let's get rid of the whole case-folding thing. Also, it doesn't seem to meet the POLA for the script to restore data only in COPY mode, so add \i commands to make it have comparable behavior in --inserts mode. Noted while looking at the tar-output code in connection with Brian Weaver's patch.
2012-09-28Fix pg_restore to accept POSIX-conformant tar files.Tom Lane
Back-patch portions of commit 05b555d12bc2ad0d581f48a12b45174db41dc10d. We need to patch pg_restore to accept either version of the magic string, in hopes of avoiding compatibility problems when 9.3 comes out. I also fixed pg_dump to write the correct 2-block EOF marker, since that won't create a compatibility problem with pg_restore and it could help with some versions of tar. Brian Weaver and Tom Lane
2012-09-19Stamp 8.4.14.REL8_4_14Tom Lane
2012-09-19Update time zone data files to tzdata release 2012f.Tom Lane
DST law changes in Fiji.
2012-09-19Translation updatesPeter Eisentraut
2012-09-14Back-patch fix and test case for bug #7516.Tom Lane
Back-patch commits 9afc6481117d2dd936e752da0424a2b6b05f6459 and b8fbbcf37f22c5e8361da939ad0fc4be18a34ca9. The first of these is really a minor code cleanup to save a few cycles, but it turns out to provide a workaround for the misoptimization problem described in bug #7516. The second commit adds a regression test case. Back-patch the fix to all active branches. The test case only works as far back as 9.0, because it relies on plpgsql which isn't installed by default before that. (I didn't have success modifying it into an all-plperl form that still provoked a crash, though this may just reflect my lack of Perl-fu.)
2012-09-09Make plperl safe against functions that are redefined while running.Tom Lane
validate_plperl_function() supposed that it could free an old plperl_proc_desc struct immediately upon detecting that it was stale. However, if a plperl function is called recursively, this could result in deleting the struct out from under an outer invocation, leading to misbehavior or crashes. Add a simple reference-count mechanism to ensure that such structs are freed only when the last reference goes away. Per investigation of bug #7516 from Marko Tiikkaja. I am not certain that this error explains his report, because he says he didn't have any recursive calls --- but it's hard to see how else it could have crashed right there. In any case, this definitely fixes some problems in the area. Back-patch to all active branches.
2012-09-07Fix PARAM_EXEC assignment mechanism to be safe in the presence of WITH.Tom Lane
The planner previously assumed that parameter Vars having the same absolute query level, varno, and varattno could safely be assigned the same runtime PARAM_EXEC slot, even though they might be different Vars appearing in different subqueries. This was (probably) safe before the introduction of CTEs, but the lazy-evalution mechanism used for CTEs means that a CTE can be executed during execution of some other subquery, causing the lifespan of Params at the same syntactic nesting level as the CTE to overlap with use of the same slots inside the CTE. In 9.1 we created additional hazards by using the same parameter-assignment technology for nestloop inner scan parameters, but it was broken before that, as illustrated by the added regression test. To fix, restructure the planner's management of PlannerParamItems so that items having different semantic lifespans are kept rigorously separated. This will probably result in complex queries using more runtime PARAM_EXEC slots than before, but the slots are cheap enough that this hardly matters. Also, stop generating PlannerParamItems containing Params for subquery outputs: all we really need to do is reserve the PARAM_EXEC slot number, and that now only takes incrementing a counter. The planning code is simpler and probably faster than before, as well as being more correct. Per report from Vik Reykja. Back-patch of commit 46c508fbcf98ac334f1e831d21021d731c882fbb into all branches that support WITH.
2012-09-06Fix "too many arguments" messages not to index off the end of argv[].Robert Haas
This affects initdb, clusterdb, reindexdb, and vacuumdb in master and 9.2; in earlier branches, only initdb is affected.
2012-09-05Restore SIGFPE handler after initializing PL/Perl.Tom Lane
Perl, for some unaccountable reason, believes it's a good idea to reset SIGFPE handling to SIG_IGN. Which wouldn't be a good idea even if it worked; but on some platforms (Linux at least) it doesn't work at all, instead resulting in forced process termination if the signal occurs. Given the lack of other complaints, it seems safe to assume that Perl never actually provokes SIGFPE and so there is no value in the setting anyway. Hence, reset it to our normal handler after initializing Perl. Report, analysis and patch by Andres Freund.
2012-08-30Back-patch recent fixes for gistchoose and gistRelocateBuildBuffersOnSplit.Tom Lane
This back-ports commits c8ba697a4bdb934f0c51424c654e8db6133ea255 and e5db11c5582b469c04a11f217a0f32c827da5dd7, which fix one definite and one speculative bug in gistchoose, and make the code a lot more intelligible as well. In 9.2 only, this also affects the largely-copied-and-pasted logic in gistRelocateBuildBuffersOnSplit. The impact of the bugs was that the functions might make poor decisions as to which index tree branch to push a new entry down into, resulting in GiST index bloat and poor performance. The fixes rectify these decisions for future insertions, but a REINDEX would be needed to clean up any existing index bloat. Alexander Korotkov, Robert Haas, Tom Lane
2012-08-30Add missing period to detail message.Robert Haas
Per note from Peter Eisentraut.
2012-08-23Fix cascading privilege revoke to notice when privileges are still held.Tom Lane
If we revoke a grant option from some role X, but X still holds the option via another grant, we should not recursively revoke the privilege from role(s) Y that X had granted it to. This was supposedly fixed as one aspect of commit 4b2dafcc0b1a579ef5daaa2728223006d1ff98e9, but I must not have tested it, because in fact that code never worked: it forgot to shift the grant-option bits back over when masking the bits being revoked. Per bug #6728 from Daniel German. Back-patch to all active branches, since this has been wrong since 8.0.
2012-08-15Fix rescan logic in nodeCtescan.Tom Lane
The previous coding essentially assumed that nodes would be rescanned in the same order they were initialized in; or at least that the "leader" of a group of CTEscans would be rescanned before any others were required to execute. Unfortunately, that isn't even a little bit true. It's possible to devise queries in which the leader isn't rescanned until other CTEscans on the same CTE have run to completion, or even in which the leader never gets a rescan call at all. The fix makes the leader specially responsible only for initial creation and final destruction of the tuplestore; rescan resets are now a symmetrically shared responsibility. This means that we might reset the tuplestore multiple times when restarting a plan subtree containing multiple CTEscans; but resetting an already-empty tuplestore is cheap enough that that doesn't seem like a problem. Per report from Adam Mackler; the new regression test cases are based on his example query. Back-patch to 8.4 where CTE scans were introduced.
2012-08-14Stamp 8.4.13.REL8_4_13Tom Lane
2012-08-14Prevent access to external files/URLs via XML entity references.Tom Lane
xml_parse() would attempt to fetch external files or URLs as needed to resolve DTD and entity references in an XML value, thus allowing unprivileged database users to attempt to fetch data with the privileges of the database server. While the external data wouldn't get returned directly to the user, portions of it could be exposed in error messages if the data didn't parse as valid XML; and in any case the mere ability to check existence of a file might be useful to an attacker. The ideal solution to this would still allow fetching of references that are listed in the host system's XML catalogs, so that documents can be validated according to installed DTDs. However, doing that with the available libxml2 APIs appears complex and error-prone, so we're not going to risk it in a security patch that necessarily hasn't gotten wide review. So this patch merely shuts off all access, causing any external fetch to silently expand to an empty string. A future patch may improve this. In HEAD and 9.2, also suppress warnings about undefined entities, which would otherwise occur as a result of not loading referenced DTDs. Previous branches don't show such warnings anyway, due to different error handling arrangements. Credit to Noah Misch for first reporting the problem, and for much work towards a solution, though this simplistic approach was not his preference. Also thanks to Daniel Veillard for consultation. Security: CVE-2012-3489
2012-08-14Translation updatesPeter Eisentraut
2012-08-14Update time zone data files to tzdata release 2012e.Tom Lane
DST law changes in Morocco; Tokelau has relocated to the other side of the International Date Line; and apparently Olson had Tokelau's GMT offset wrong by an hour even before that. There are also a large number of non-significant changes in this update. Upstream took the opportunity to remove trailing whitespace, and the SCCS-style version numbers on the individual files are gone too.
2012-08-08fsync backup_label after pg_start_backup()Simon Riggs
Dave Kerr, backpatched by Simon Riggs
2012-08-03Fix bugs with parsing signed hh:mm and hh:mm:ss fields in interval input.Tom Lane
DecodeInterval() failed to honor the "range" parameter (the special SQL syntax for indicating which fields appear in the literal string) if the time was signed. This seems inappropriate, so make it work like the not-signed case. The inconsistency was introduced in my commit f867339c0148381eb1d01f93ab5c79f9d10211de, which as noted in its log message was only really focused on making SQL-compliant literals work per spec. Including a sign here is not per spec, but if we're going to allow it then it's reasonable to expect it to work like the not-signed case. Also, remove bogus setting of tmask, which caused subsequent processing to think that what had been given was a timezone and not an hh:mm(:ss) field, thus confusing checks for redundant fields. This seems to be an aboriginal mistake in Lockhart's commit 2cf1642461536d0d8f3a1cf124ead0eac04eb760. Add regression test cases to illustrate the changed behaviors. Back-patch as far as 8.4, where support for spec-compliant interval literals was added. Range problem reported and diagnosed by Amit Kapila, tmask problem by me.
2012-07-31Fix WITH attached to a nested set operation (UNION/INTERSECT/EXCEPT).Tom Lane
Parse analysis neglected to cover the case of a WITH clause attached to an intermediate-level set operation; it only handled WITH at the top level or WITH attached to a leaf-level SELECT. Per report from Adam Mackler. In HEAD, I rearranged the order of SelectStmt's fields to put withClause with the other fields that can appear on non-leaf SelectStmts. In back branches, leave it alone to avoid a possible ABI break for third-party code. Back-patch to 8.4 where WITH support was added.
2012-07-31Fix syslogger so that log_truncate_on_rotation works in the first rotation.Tom Lane
In the original coding of the log rotation stuff, we did not bother to make the truncation logic work for the very first rotation after postmaster start (or after a syslogger crash and restart). It just always appended in that case. It did not seem terribly important at the time, but we've recently had two separate complaints from people who expected it to work unsurprisingly. (Both users tend to restart the postmaster about as often as a log rotation is configured to happen, which is maybe not typical use, but still...) Since the initial log file is opened in the postmaster, fixing this requires passing down some more state to the syslogger child process. It's always been like this, so back-patch to all supported branches.
2012-07-27Improve reporting of error situations in find_other_exec().Tom Lane
This function suppressed any stderr output from the called program, which is unnecessary in the normal case and unhelpful in error cases. It also gave a rather opaque message along the lines of "fgets failure: Success" in case the called program failed to return anything on stdout. Since we've seen multiple reports of people not understanding what's wrong when pg_ctl reports this, improve the message. Back-patch to all active branches.
2012-07-26Only allow autovacuum to be auto-canceled by a directly blocked process.Tom Lane
In the original coding of the autovacuum cancel feature, commit acac68b2bcae818bc8803b8cb8cbb17eee8d5e2b, an autovacuum process was considered a target for cancellation if it was found to hard-block any process examined in the deadlock search. This patch tightens the test so that the autovacuum must directly hard-block the current process. This should make the behavior more predictable in general, and in particular it ensures that an autovacuum will not be canceled with less than deadlock_timeout grace period. In the old coding, it was possible for an autovacuum to be canceled almost instantly, given unfortunate timing of two or more other processes' lock attempts. This also justifies the logging methodology in the recent commit d7318d43d891bd63e82dcfc27948113ed7b1db80; without this restriction, that patch isn't providing enough information to see the connection of the canceling process to the autovacuum. Like that one, patch all the way back.
2012-07-26Log a better message when canceling autovacuum.Robert Haas
The old message was at DEBUG2, so typically it didn't show up in the log at all. As a result, in most cases where autovacuum was canceled, the only information that was logged was the table being vacuumed, with no indication as to what problem caused the cancel. Crank up the level to LOG and add some more details to assist with debugging. Back-patch all the way, per discussion on pgsql-hackers.
2012-07-25Fix longstanding crash-safety bug with newly-created-or-reset sequences.Tom Lane
If a crash occurred immediately after the first nextval() call for a serial column, WAL replay would restore the sequence to a state in which it appeared that no nextval() had been done, thus allowing the first sequence value to be returned again by the next nextval() call; as reported in bug #6748 from Xiangming Mei. More generally, the problem would occur if an ALTER SEQUENCE was executed on a freshly created or reset sequence. (The manifestation with serial columns was introduced in 8.2 when we added an ALTER SEQUENCE OWNED BY step to serial column creation.) The cause is that sequence creation attempted to save one WAL entry by writing out a WAL record that made it appear that the first nextval() had already happened (viz, with is_called = true), while marking the sequence's in-database state with log_cnt = 1 to show that the first nextval() need not emit a WAL record. However, ALTER SEQUENCE would emit a new WAL entry reflecting the actual in-database state (with is_called = false). Then, nextval would allocate the first sequence value and set is_called = true, but it would trust the log_cnt value and not emit any WAL record. A crash at this point would thus restore the sequence to its post-ALTER state, causing the next nextval() call to return the first sequence value again. To fix, get rid of the idea of logging an is_called status different from reality. This means that the first nextval-driven WAL record will happen at the first nextval call not the second, but the marginal cost of that is pretty negligible. In addition, make sure that ALTER SEQUENCE resets log_cnt to zero in any case where it touches sequence parameters that affect future nextval results. This will result in some user-visible changes in the contents of a sequence's log_cnt column, as reflected in the patch's regression test changes; but no application should be depending on that anyway, since it was already true that log_cnt changes rather unpredictably depending on checkpoint timing. In addition, make some basically-cosmetic improvements to get rid of sequence.c's undesirable intimacy with page layout details. It was always really trying to WAL-log the contents of the sequence tuple, so we should have it do that directly using a HeapTuple's t_data and t_len, rather than backing into it with some magic assumptions about where the tuple would be on the sequence's page. Back-patch to all supported branches.