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2018-09-02Fix initial sync of slot parent directory when restoring statusMichael Paquier
At the beginning of recovery, information from replication slots is recovered from disk to memory. In order to ensure the durability of the information, the status file as well as its parent directory are synced. It happens that the sync on the parent directory was done directly using the status file path, which is logically incorrect, and the current code has been doing a sync on the same object twice in a row. Reported-by: Konstantin Knizhnik Diagnosed-by: Konstantin Knizhnik Author: Michael Paquier Discussion: https://postgr.es/m/9eb1a6d5-b66f-2640-598d-c5ea46b8f68a@postgrespro.ru Backpatch-through: 9.4-
2018-09-01Avoid using potentially-under-aligned page buffers.Tom Lane
There's a project policy against using plain "char buf[BLCKSZ]" local or static variables as page buffers; preferred style is to palloc or malloc each buffer to ensure it is MAXALIGN'd. However, that policy's been ignored in an increasing number of places. We've apparently got away with it so far, probably because (a) relatively few people use platforms on which misalignment causes core dumps and/or (b) the variables chance to be sufficiently aligned anyway. But this is not something to rely on. Moreover, even if we don't get a core dump, we might be paying a lot of cycles for misaligned accesses. To fix, invent new union types PGAlignedBlock and PGAlignedXLogBlock that the compiler must allocate with sufficient alignment, and use those in place of plain char arrays. I used these types even for variables where there's no risk of a misaligned access, since ensuring proper alignment should make kernel data transfers faster. I also changed some places where we had been palloc'ing short-lived buffers, for coding style uniformity and to save palloc/pfree overhead. Since this seems to be a live portability hazard (despite the lack of field reports), back-patch to all supported versions. Patch by me; thanks to Michael Paquier for review. Discussion: https://postgr.es/m/1535618100.1286.3.camel@credativ.de
2018-08-31Ignore server-side delays when enforcing wal_sender_timeout.Noah Misch
Healthy clients of servers having poor I/O performance, such as buildfarm members hamster and tern, saw unexpected timeouts. That disagreed with documentation. This fix adds one gettimeofday() call whenever ProcessRepliesIfAny() finds no client reply messages. Back-patch to 9.4; the bug's symptom is rare and mild, and the code all moved between 9.3 and 9.4. Discussion: https://postgr.es/m/20180826034600.GA1105084@rfd.leadboat.com
2018-08-31Ensure correct minimum consistent point on standbysMichael Paquier
Startup process has improved its calculation of incorrect minimum consistent point in 8d68ee6, which ensures that all WAL available gets replayed when doing crash recovery, and has introduced an incorrect calculation of the minimum recovery point for non-startup processes, which can cause incorrect page references on a standby when for example the background writer flushed a couple of pages on-disk but was not updating the control file to let a subsequent crash recovery replay to where it should have. The only case where this has been reported to be a problem is when a standby needs to calculate the latest removed xid when replaying a btree deletion record, so one would need connections on a standby that happen just after recovery has thought it reached a consistent point. Using a background worker which is started after the consistent point is reached would be the easiest way to get into problems if it connects to a database. Having clients which attempt to connect periodically could also be a problem, but the odds of seeing this problem are much lower. The fix used is pretty simple, as the idea is to give access to the minimum recovery point written in the control file to non-startup processes so as they use a reference, while the startup process still initializes its own references of the minimum consistent point so as the original problem with incorrect page references happening post-promotion with a crash do not show up. Reported-by: Alexander Kukushkin Diagnosed-by: Alexander Kukushkin Author: Michael Paquier Reviewed-by: Kyotaro Horiguchi, Alexander Kukushkin Discussion: https://postgr.es/m/153492341830.1368.3936905691758473953@wrigleys.postgresql.org Backpatch-through: 9.3
2018-08-31Make checksum_impl.h safe to compile with -fstrict-aliasing.Tom Lane
In general, Postgres requires -fno-strict-aliasing with compilers that implement C99 strict aliasing rules. There's little hope of getting rid of that overall. But it seems like it would be a good idea if storage/checksum_impl.h in particular didn't depend on it, because that header is explicitly intended to be included by external programs. We don't have a lot of control over the compiler switches that an external program might use, as shown by Michael Banck's report of failure in a privately-modified version of pg_verify_checksums. Hence, switch to using a union in place of willy-nilly pointer casting inside this file. I think this makes the code a bit more readable anyway. checksum_impl.h hasn't changed since it was introduced in 9.3, so back-patch all the way. Discussion: https://postgr.es/m/1535618100.1286.3.camel@credativ.de
2018-08-28Avoid quadratic slowdown in regexp match/split functions.Andrew Gierth
regexp_matches, regexp_split_to_table and regexp_split_to_array all work by compiling a list of match positions as character offsets (NOT byte positions) in the source string. Formerly, they then used text_substr to extract the matched text; but in a multi-byte encoding, that counts the characters in the string, and the characters needed to reach the starting byte position, on every call. Accordingly, the performance degraded as the product of the input string length and the number of match positions, such that splitting a string of a few hundred kbytes could take many minutes. Repair by keeping the wide-character copy of the input string available (only in the case where encoding_max_length is not 1) after performing the match operation, and extracting substrings from that instead. This reduces the complexity to being linear in the number of result bytes, discounting the actual regexp match itself (which is not affected by this patch). In passing, remove cleanup using retail pfree() which was obsoleted by commit ff428cded (Feb 2008) which made cleanup of SRF multi-call contexts automatic. Also increase (to ~134 million) the maximum number of matches and provide an error message when it is reached. Backpatch all the way because this has been wrong forever. Analysis and patch by me; review by Kaiting Chen. Discussion: https://postgr.es/m/87pnyn55qh.fsf@news-spur.riddles.org.uk see also https://postgr.es/m/87lg996g4r.fsf@news-spur.riddles.org.uk
2018-08-26Make syslogger more robust against failures in opening CSV log files.Tom Lane
The previous coding figured it'd be good enough to postpone opening the first CSV log file until we got a message we needed to write there. This is unsafe, though, because if the open fails we end up in infinite recursion trying to report the failure. Instead make the CSV log file management code look as nearly as possible like the longstanding logic for the stderr log file. In particular, open it immediately at postmaster startup (if enabled), or when we get a SIGHUP in which we find that log_destination has been changed to enable CSV logging. It seems OK to fail if a postmaster-start-time open attempt fails, as we've long done for the stderr log file. But we can't die if we fail to open a CSV log file during SIGHUP, so we're still left with a problem. In that case, write any output meant for the CSV log file to the stderr log file. (This will also cover race-condition cases in which backends send CSV log data before or after we have the CSV log file open.) This patch also fixes an ancient oversight that, if CSV logging was turned off during a SIGHUP, we never actually closed the last CSV log file. In passing, remember to reset whereToSendOutput = DestNone during syslogger start, since (unlike all other postmaster children) it's forked before the postmaster has done that. This made for a platform-dependent difference in error reporting behavior between the syslogger and other children: except on Windows, it'd report problems to the original postmaster stderr as well as the normal error log file(s). It's barely possible that that was intentional at some point; but it doesn't seem likely to be desirable in production, and the platform dependency definitely isn't desirable. Per report from Alexander Kukushkin. It's been like this for a long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/CAFh8B==iLUD_gqC-dAENS0V+kVrCeGiKujtKqSQ7++S-caaChw@mail.gmail.com
2018-08-23Reduce an unnecessary O(N^3) loop in lexer.Andrew Gierth
The lexer's handling of operators contained an O(N^3) hazard when dealing with long strings of + or - characters; it seems hard to prevent this case from being O(N^2), but the additional N multiplier was not needed. Backpatch all the way since this has been there since 7.x, and it presents at least a mild hazard in that trying to do Bind, PREPARE or EXPLAIN on a hostile query could take excessive time (without honouring cancels or timeouts) even if the query was never executed.
2018-08-21Fix set of NLS translation issuesMichael Paquier
While monitoring the code, a couple of issues related to string translation has showed up: - Some routines for auto-updatable views return an error string, which sometimes missed the shot. A comment regarding string translation is added for each routine to help with future features. - GSSAPI authentication missed two translations. Reported-by: Kyotaro Horiguchi Author: Kyotaro Horiguchi Reviewed-by: Michael Paquier, Tom Lane Discussion: https://postgr.es/m/20180810.152131.31921918.horiguchi.kyotaro@lab.ntt.co.jp Backpatch-through: 9.3
2018-08-17Ensure schema qualification in pg_restore DISABLE/ENABLE TRIGGER commands.Tom Lane
Previously, this code blindly followed the common coding pattern of passing PQserverVersion(AH->connection) as the server-version parameter of fmtQualifiedId. That works as long as we have a connection; but in pg_restore with text output, we don't. Instead we got a zero from PQserverVersion, which fmtQualifiedId interpreted as "server is too old to have schemas", and so the name went unqualified. That still accidentally managed to work in many cases, which is probably why this ancient bug went undetected for so long. It only became obvious in the wake of the changes to force dump/restore to execute with restricted search_path. In HEAD/v11, let's deal with this by ripping out fmtQualifiedId's server- version behavioral dependency, and just making it schema-qualify all the time. We no longer support pg_dump from servers old enough to need the ability to omit schema name, let alone restoring to them. (Also, the few callers outside pg_dump already didn't work with pre-schema servers.) In older branches, that's not an acceptable solution, so instead just tweak the DISABLE/ENABLE TRIGGER logic to ensure it will schema-qualify its output regardless of server version. Per bug #15338 from Oleg somebody. Back-patch to all supported branches. Discussion: https://postgr.es/m/153452458706.1316.5328079417086507743@wrigleys.postgresql.org
2018-08-17Set scan direction appropriately for SubPlans (bug #15336)Andrew Gierth
When executing a SubPlan in an expression, the EState's direction field was left alone, resulting in an attempt to execute the subplan backwards if it was encountered during a backwards scan of a cursor. Also, though much less likely, it was possible to reach the execution of an InitPlan while in backwards-scan state. Repair by saving/restoring estate->es_direction and forcing forward scan mode in the relevant places. Backpatch all the way, since this has been broken since 8.3 (prior to commit c7ff7663e, SubPlans had their own EStates rather than sharing the parent plan's, so there was no confusion over scan direction). Per bug #15336 reported by Vladimir Baranoff; analysis and patch by me, review by Tom Lane. Discussion: https://postgr.es/m/153449812167.1304.1741624125628126322@wrigleys.postgresql.org
2018-08-16Close the file descriptor in ApplyLogicalMappingFileTomas Vondra
The function was forgetting to close the file descriptor, resulting in failures like this: ERROR: 53000: exceeded maxAllocatedDescs (492) while trying to open file "pg_logical/mappings/map-4000-4eb-1_60DE1E08-5376b5-537c6b" LOCATION: OpenTransientFile, fd.c:2161 Simply close the file at the end, and backpatch to 9.4 (where logical decoding was introduced). While at it, fix a nearby typo. Discussion: https://www.postgresql.org/message-id/flat/738a590a-2ce5-9394-2bef-7b1caad89b37%402ndquadrant.com
2018-08-15Make snprintf.c follow the C99 standard for snprintf's result value.Tom Lane
C99 says that the result should be the number of bytes that would have been emitted given a large enough buffer, not the number we actually were able to put in the buffer. It's time to make our substitute implementation comply with that. Not doing so results in inefficiency in buffer-enlargement cases, and also poses a portability hazard for third-party code that might expect C99-compliant snprintf behavior within Postgres. In passing, remove useless tests for str == NULL; neither C99 nor predecessor standards ever allowed that except when count == 0, so I see no reason to expend cycles on making that a non-crash case for this implementation. Also, don't waste a byte in pg_vfprintf's local I/O buffer; this might have performance benefits by allowing aligned writes during flushbuffer calls. Back-patch of commit 805889d7d. There was some concern about this possibly breaking code that assumes pre-C99 behavior, but there is much more risk (and reality, in our own code) of code that assumes C99 behavior and hence fails to detect buffer overrun without this. Discussion: https://postgr.es/m/17245.1534289329@sss.pgh.pa.us
2018-08-15Clean up assorted misuses of snprintf()'s result value.Tom Lane
Fix a small number of places that were testing the result of snprintf() but doing so incorrectly. The right test for buffer overrun, per C99, is "result >= bufsize" not "result > bufsize". Some places were also checking for failure with "result == -1", but the standard only says that a negative value is delivered on failure. (Note that this only makes these places correct if snprintf() delivers C99-compliant results. But at least now these places are consistent with all the other places where we assume that.) Also, make psql_start_test() and isolation_start_test() check for buffer overrun while constructing their shell commands. There seems like a higher risk of overrun, with more severe consequences, here than there is for the individual file paths that are made elsewhere in the same functions, so this seemed like a worthwhile change. Also fix guc.c's do_serialize() to initialize errno = 0 before calling vsnprintf. In principle, this should be unnecessary because vsnprintf should have set errno if it returns a failure indication ... but the other two places this coding pattern is cribbed from don't assume that, so let's be consistent. These errors are all very old, so back-patch as appropriate. I think that only the shell command overrun cases are even theoretically reachable in practice, but there's not much point in erroneous error checks. Discussion: https://postgr.es/m/17245.1534289329@sss.pgh.pa.us
2018-08-08Don't run atexit callbacks in quickdie signal handlers.Heikki Linnakangas
exit() is not async-signal safe. Even if the libc implementation is, 3rd party libraries might have installed unsafe atexit() callbacks. After receiving SIGQUIT, we really just want to exit as quickly as possible, so we don't really want to run the atexit() callbacks anyway. The original report by Jimmy Yih was a self-deadlock in startup_die(). However, this patch doesn't address that scenario; the signal handling while waiting for the startup packet is more complicated. But at least this alleviates similar problems in the SIGQUIT handlers, like that reported by Asim R P later in the same thread. Backpatch to 9.3 (all supported versions). Discussion: https://www.postgresql.org/message-id/CAOMx_OAuRUHiAuCg2YgicZLzPVv5d9_H4KrL_OFsFP%3DVPekigA%40mail.gmail.com
2018-08-07Don't record FDW user mappings as members of extensions.Tom Lane
CreateUserMapping has a recordDependencyOnCurrentExtension call that's been there since extensions were introduced (very possibly my fault). However, there's no support anywhere else for user mappings as members of extensions, nor are they listed as a possible member object type in the documentation. Nor does it really seem like a good idea for user mappings to belong to extensions when roles don't. Hence, remove the bogus call. (As we saw in bug #15310, the lack of any pg_dump support for this case ensures that any such membership record would silently disappear during pg_upgrade. So there's probably no need for us to do anything else about cleaning up after this mistake.) Discussion: https://postgr.es/m/27952.1533667213@sss.pgh.pa.us
2018-08-07Fix incorrect initialization of BackendActivityBuffer.Tom Lane
Since commit c8e8b5a6e, this has been zeroed out using the wrong length. In practice the length would always be too small, leading to not zeroing the whole buffer rather than clobbering additional memory; and that's pretty harmless, both because shmem would likely start out as zeroes and because we'd reinitialize any given entry before use. Still, it's bogus, so fix it. Reported by Petru-Florin Mihancea (bug #15312) Discussion: https://postgr.es/m/153363913073.1303.6518849192351268091@wrigleys.postgresql.org
2018-08-07Fix pg_upgrade to handle event triggers in extensions correctly.Tom Lane
pg_dump with --binary-upgrade must emit ALTER EXTENSION ADD commands for all objects that are members of extensions. It forgot to do so for event triggers, as per bug #15310 from Nick Barnes. Back-patch to 9.3 where event triggers were introduced. Haribabu Kommi Discussion: https://postgr.es/m/153360083872.1395.4593932457718151600@wrigleys.postgresql.org
2018-08-07Ensure pg_dump_sort.c sorts null vs non-null namespace consistently.Tom Lane
The original coding here (which is, I believe, my fault) supposed that it didn't need to concern itself with the possibility that one object of a given type-priority has a namespace while another doesn't. But that's not reliably true anymore, if it ever was; and if it does happen then it's possible that DOTypeNameCompare returns self-inconsistent comparison results. That leads to unspecified behavior in qsort() and a resultant weird output order from pg_dump. This should end up being only a cosmetic problem, because any ordering constraints that actually matter should be enforced by the later dependency-based sort. Still, it's a bug, so back-patch. Report and fix by Jacob Champion, though I editorialized on his patch to the extent of making NULL sort after non-NULL, for consistency with our usual sorting definitions. Discussion: https://postgr.es/m/CABAq_6Hw+V-Kj7PNfD5tgOaWT_-qaYkc+SRmJkPLeUjYXLdxwQ@mail.gmail.com
2018-08-06Stamp 9.4.19.REL9_4_19Tom Lane
2018-08-06Translation updatesPeter Eisentraut
Source-Git-URL: https://git.postgresql.org/git/pgtranslation/messages.git Source-Git-Hash: a69444e557347b0db244ac3d3ea2bf602a82227f
2018-08-06Fix failure to reset libpq's state fully between connection attempts.Tom Lane
The logic in PQconnectPoll() did not take care to ensure that all of a PGconn's internal state variables were reset before trying a new connection attempt. If we got far enough in the connection sequence to have changed any of these variables, and then decided to try a new server address or server name, the new connection might be completed with some state that really only applied to the failed connection. While this has assorted bad consequences, the only one that is clearly a security issue is that password_needed didn't get reset, so that if the first server asked for a password and the second didn't, PQconnectionUsedPassword() would return an incorrect result. This could be leveraged by unprivileged users of dblink or postgres_fdw to allow them to use server-side login credentials that they should not be able to use. Other notable problems include the possibility of forcing a v2-protocol connection to a server capable of supporting v3, or overriding "sslmode=prefer" to cause a non-encrypted connection to a server that would have accepted an encrypted one. Those are certainly bugs but it's harder to paint them as security problems in themselves. However, forcing a v2-protocol connection could result in libpq having a wrong idea of the server's standard_conforming_strings setting, which opens the door to SQL-injection attacks. The extent to which that's actually a problem, given the prerequisite that the attacker needs control of the client's connection parameters, is unclear. These problems have existed for a long time, but became more easily exploitable in v10, both because it introduced easy ways to force libpq to abandon a connection attempt at a late stage and then try another one (rather than just giving up), and because it provided an easy way to specify multiple target hosts. Fix by rearranging PQconnectPoll's state machine to provide centralized places to reset state properly when moving to a new target host or when dropping and retrying a connection to the same host. Tom Lane, reviewed by Noah Misch. Our thanks to Andrew Krasichkov for finding and reporting the problem. Security: CVE-2018-10915
2018-08-05Reset properly errno before calling write()Michael Paquier
6cb3372 enforces errno to ENOSPC when less bytes than what is expected have been written when it is unset, though it forgot to properly reset errno before doing a system call to write(), causing errno to potentially come from a previous system call. Reported-by: Tom Lane Author: Michael Paquier Reviewed-by: Tom Lane Discussion: https://postgr.es/m/31797.1533326676@sss.pgh.pa.us
2018-08-03Add table relcache invalidation to index builds.Peter Geoghegan
It's necessary to make sure that owning tables have a relcache invalidation prior to advancing the command counter to make newly-entered catalog tuples for the index visible. inval.c must be able to maintain the consistency of the local caches in the event of transaction abort. There is usually only a problem when CREATE INDEX transactions abort, since there is a generic invalidation once we reach index_update_stats(). This bug is of long standing. Problems were made much more likely by the addition of parallel CREATE INDEX (commit 9da0cc35284), but it is strongly suspected that similar problems can be triggered without involving plan_create_index_workers(). (plan_create_index_workers() triggers a relcache build or rebuild, which previously only happened in rare edge cases.) Author: Peter Geoghegan Reported-By: Luca Ferrari Diagnosed-By: Andres Freund Reviewed-By: Andres Freund Discussion: https://postgr.es/m/CAKoxK+5fVodiCtMsXKV_1YAKXbzwSfp7DgDqUmcUAzeAhf=HEQ@mail.gmail.com Backpatch: 9.3-
2018-07-31Further fixes for quoted-list GUC values in pg_dump and ruleutils.c.Tom Lane
Commits 742869946 et al turn out to be a couple bricks shy of a load. We were dumping the stored values of GUC_LIST_QUOTE variables as they appear in proconfig or setconfig catalog columns. However, although that quoting rule looks a lot like SQL-identifier double quotes, there are two critical differences: empty strings ("") are legal, and depending on which variable you're considering, values longer than NAMEDATALEN might be valid too. So the current technique fails altogether on empty-string list entries (as reported by Steven Winfield in bug #15248) and it also risks truncating file pathnames during dump/reload of GUC values that are lists of pathnames. To fix, split the stored value without any downcasing or truncation, and then emit each element as a SQL string literal. This is a tad annoying, because we now have three copies of the comma-separated-string splitting logic in varlena.c as well as a fourth one in dumputils.c. (Not to mention the randomly-different-from-those splitting logic in libpq...) I looked at unifying these, but it would be rather a mess unless we're willing to tweak the API definitions of SplitIdentifierString, SplitDirectoriesString, or both. That might be worth doing in future; but it seems pretty unsafe for a back-patched bug fix, so for now accept the duplication. Back-patch to all supported branches, as the previous fix was. Discussion: https://postgr.es/m/7585.1529435872@sss.pgh.pa.us
2018-07-30Fix pg_dump's failure to dump REPLICA IDENTITY for constraint indexes.Tom Lane
pg_dump knew about printing ALTER TABLE ... REPLICA IDENTITY USING INDEX for indexes declared as indexes, but it failed to print that for indexes declared as unique or primary-key constraints. Per report from Achilleas Mantzios. This has been broken since the feature was introduced, AFAICS. Back-patch to 9.4. Discussion: https://postgr.es/m/1e6cc5ad-b84a-7c07-8c08-a4d0c3cdc938@matrix.gatewaynet.com
2018-07-28Document security implications of qualified names.Noah Misch
Commit 5770172cb0c9df9e6ce27c507b449557e5b45124 documented secure schema usage, and that advice suffices for using unqualified names securely. Document, in typeconv-func primarily, the additional issues that arise with qualified names. Back-patch to 9.3 (all supported versions). Reviewed by Jonathan S. Katz. Discussion: https://postgr.es/m/20180721012446.GA1840594@rfd.leadboat.com
2018-07-19Fix handling of empty uncompressed posting list pages in GINAlexander Korotkov
PostgreSQL 9.4 introduces posting list compression in GIN. This feature supports online upgrade, so that after pg_upgrade uncompressed posting lists are compressed on-the-fly. Underlying code appears to always expect at least one item on uncompressed posting list page. But there could be completely empty pages, because VACUUM never deletes leftmost and rightmost pages from posting trees. This commit fixes that. Reported-by: Sivasubramanian Ramasubramanian Discussion: https://postgr.es/m/1531867212836.63354%40amazon.com Author: Sivasubramanian Ramasubramanian, Alexander Korotkov Backpatch-through: 9.4
2018-07-18Fix misc typos, mostly in comments.Heikki Linnakangas
A collection of typos I happened to spot while reading code, as well as grepping for common mistakes. Backpatch to all supported versions, as applicable, to avoid conflicts when backporting other commits in the future.
2018-07-13Fix inadequate buffer locking in FSM and VM page re-initialization.Tom Lane
When reading an existing FSM or VM page that was found to be corrupt by the buffer manager, the code applied PageInit() to reinitialize the page, but did so without any locking. There is thus a hazard that two backends might concurrently do PageInit, which in itself would still be OK, but the slower one might then zero over subsequent data changes applied by the faster one. Even that is unlikely to be fatal; but it's not desirable, so add locking to prevent it. This does not add any locking overhead in the normal code path where the page is OK. It's not immediately obvious that that's safe, but I believe it is, for reasons explained in the added comments. Problem noted by R P Asim. It's been like this for a long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/CANXE4Te4G0TGq6cr0-TvwP0H4BNiK_-hB5gHe8mF+nz0mcYfMQ@mail.gmail.com
2018-07-12Make logical WAL sender report streaming state appropriatelyMichael Paquier
WAL senders sending logically-decoded data fail to properly report in "streaming" state when starting up, hence as long as one extra record is not replayed, such WAL senders would remain in a "catchup" state, which is inconsistent with the physical cousin. This can be easily reproduced by for example using pg_recvlogical and restarting the upstream server. The TAP tests have been slightly modified to detect the failure and strengthened so as future tests also make sure that a node is in streaming state when waiting for its catchup. Backpatch down to 9.4 where this code has been introduced. Reported-by: Sawada Masahiko Author: Simon Riggs, Sawada Masahiko Reviewed-by: Petr Jelinek, Michael Paquier, Vaishnavi Prabakaran Discussion: https://postgr.es/m/CAD21AoB2ZbCCqOx=bgKMcLrAvs1V0ZMqzs7wBTuDySezTGtMZA@mail.gmail.com
2018-07-09Avoid emitting a bogus WAL record when recycling an all-zero btree page.Tom Lane
Commit fafa374f2 caused _bt_getbuf() to possibly emit a WAL record for a page that it was about to recycle. However, it failed to distinguish all-zero pages from dead pages, which is important because only the latter have valid btpo.xact values, or indeed any special space at all. Recycling an all-zero page with XLogStandbyInfoActive() enabled therefore led to an Assert failure, or to emission of a WAL record containing a bogus cutoff XID, which might lead to unnecessary query cancellations on hot standby servers. Per reports from Antonin Houska and 自己. Amit Kapila was first to propose this fix, and Robert Haas, myself, and Kyotaro Horiguchi reviewed it at various times. This is an old bug, so back-patch to all supported branches. Discussion: https://postgr.es/m/2628.1474272158@localhost Discussion: https://postgr.es/m/48875502.f4a0.1635f0c27b0.Coremail.zoulx1982@163.com
2018-07-09Prevent accidental linking of system-supplied copies of libpq.so etc.Tom Lane
Back-patch commit dddfc4cb2, which broke LDFLAGS and related Makefile variables into two parts, one for within-build-tree library references and one for external libraries, to ensure that the order of -L flags has all of the former before all of the latter. This turns out to fix a problem recently noted on buildfarm member peripatus, that we attempted to incorporate code from libpgport.a into a shared library. That will fail on platforms that are sticky about putting non-PIC code into shared libraries. (It's quite surprising we hadn't seen such failures before, since the code in question has been like that for a long time.) I think that peripatus' problem could have been fixed with just a subset of this patch; but since the previous issue of accidentally linking to the wrong copy of a Postgres shlib seems likely to bite people in the field, let's just back-patch the whole change. Now that commit dddfc4cb2 has survived some beta testing, I'm less afraid to back-patch it than I was at the time. This also fixes undesired inclusion of "-DFRONTEND" in pg_config's CPPFLAGS output (in 9.6 and up) and undesired inclusion of "-L../../src/common" in its LDFLAGS output (in all supported branches). Back-patch to v10 and older branches; this is already in v11. Discussion: https://postgr.es/m/20180704234304.bq2dxispefl65odz@ler-imac.local
2018-07-05Prevent references to invalid relation pages after fresh promotionMichael Paquier
If a standby crashes after promotion before having completed its first post-recovery checkpoint, then the minimal recovery point which marks the LSN position where the cluster is able to reach consistency may be set to a position older than the first end-of-recovery checkpoint while all the WAL available should be replayed. This leads to the instance thinking that it contains inconsistent pages, causing a PANIC and a hard instance crash even if all the WAL available has not been replayed for certain sets of records replayed. When in crash recovery, minRecoveryPoint is expected to always be set to InvalidXLogRecPtr, which forces the recovery to replay all the WAL available, so this commit makes sure that the local copy of minRecoveryPoint from the control file is initialized properly and stays as it is while crash recovery is performed. Once switching to archive recovery or if crash recovery finishes, then the local copy minRecoveryPoint can be safely updated. Pavan Deolasee has reported and diagnosed the failure in the first place, and the base fix idea to rely on the local copy of minRecoveryPoint comes from Kyotaro Horiguchi, which has been expanded into a full-fledged patch by me. The test included in this commit has been written by Álvaro Herrera and Pavan Deolasee, which I have modified to make it faster and more reliable with sleep phases. Backpatch down to all supported versions where the bug appears, aka 9.3 which is where the end-of-recovery checkpoint is not run by the startup process anymore. The test gets easily supported down to 10, still it has been tested on all branches. Reported-by: Pavan Deolasee Diagnosed-by: Pavan Deolasee Reviewed-by: Pavan Deolasee, Kyotaro Horiguchi Author: Michael Paquier, Kyotaro Horiguchi, Pavan Deolasee, Álvaro Herrera Discussion: https://postgr.es/m/CABOikdPOewjNL=05K5CbNMxnNtXnQjhTx2F--4p4ruorCjukbA@mail.gmail.com
2018-07-04Check for interrupts inside the nbtree page deletion code.Andres Freund
When deleting pages the nbtree code has to walk through siblings of a tree node. When those sibling links are corrupted that can lead to endless loops - which are currently not interruptible. This is especially problematic if autovacuum is repeatedly blocked on such indexes, as it can be hard to get out of that situation without resorting to single user mode. Thus add interrupt checks to appropriate places in such loops. Unfortunately in one of the cases it's it's not easy to do so. Between 9.3 and 9.4 the page deletion (and page split) code changed significantly. Before it was significantly less robust against interruptions. Therefore don't backpatch to 9.3. Author: Andres Freund Discussion: https://postgr.es/m/20180627191629.wkunw2qbibnvlz53@alap3.anarazel.de Backpatch: 9.4-
2018-07-05Improve the performance of relation deletes during recovery.Fujii Masao
When multiple relations are deleted at the same transaction, the files of those relations are deleted by one call to smgrdounlinkall(), which leads to scan whole shared_buffers only one time. OTOH, previously, during recovery, smgrdounlink() (not smgrdounlinkall()) was called for each file to delete, which led to scan shared_buffers multiple times. Obviously this could cause to increase the WAL replay time very much especially when shared_buffers was huge. To alleviate this situation, this commit changes the recovery so that it also calls smgrdounlinkall() only one time to delete multiple relation files. This is just fix for oversight of commit 279628a0a7, not new feature. So, per discussion on pgsql-hackers, we concluded to backpatch this to all supported versions. Author: Fujii Masao Reviewed-by: Michael Paquier, Andres Freund, Thomas Munro, Kyotaro Horiguchi, Takayuki Tsunakawa Discussion: https://postgr.es/m/CAHGQGwHVQkdfDqtvGVkty+19cQakAydXn1etGND3X0PHbZ3+6w@mail.gmail.com
2018-07-01Fix libpq example programsPeter Eisentraut
When these programs call pg_catalog.set_config, they need to check for PGRES_TUPLES_OK instead of PGRES_COMMAND_OK. Fix for 5770172cb0c9df9e6ce27c507b449557e5b45124. Reported-by: Ideriha, Takeshi <ideriha.takeshi@jp.fujitsu.com>
2018-06-26Fix "base" snapshot handling in logical decodingAlvaro Herrera
Two closely related bugs are fixed. First, xmin of logical slots was advanced too early. During xl_running_xacts processing, xmin of the slot was set to the oldest running xid in the record, but that's wrong: actually, snapshots which will be used for not-yet-replayed transactions might consider older txns as running too, so we need to keep xmin back for them. The problem wasn't noticed earlier because DDL which allows to delete tuple (set xmax) while some another not-yet-committed transaction looks at it is pretty rare, if not unique: e.g. all forms of ALTER TABLE which change schema acquire ACCESS EXCLUSIVE lock conflicting with any inserts. The included test case (test_decoding's oldest_xmin) uses ALTER of a composite type, which doesn't have such interlocking. To deal with this, we must be able to quickly retrieve oldest xmin (oldest running xid among all assigned snapshots) from ReorderBuffer. To fix, add another list of ReorderBufferTXNs to the reorderbuffer, where transactions are sorted by base-snapshot-LSN. This is slightly different from the existing (sorted by first-LSN) list, because a transaction can have an earlier LSN but a later Xmin, if its first record does not obtain an xmin (eg. xl_xact_assignment). Note this new list doesn't fully replace the existing txn list: we still need that one to prevent WAL recycling. The second issue concerns SnapBuilder snapshots and subtransactions. SnapBuildDistributeNewCatalogSnapshot never assigned a snapshot to a transaction that is known to be a subtxn, which is good in the common case that the top-level transaction already has one (no point in doing so), but a bug otherwise. To fix, arrange to transfer the snapshot from the subtxn to its top-level txn as soon as the kinship gets known. test_decoding's snapshot_transfer verifies this. Also, fix a minor memory leak: refcount of toplevel's old base snapshot was not decremented when the snapshot is transferred from child. Liberally sprinkle code comments, and rewrite a few existing ones. This part is my (Álvaro's) contribution to this commit, as I had to write all those comments in order to understand the existing code and Arseny's patch. Reported-by: Arseny Sher <a.sher@postgrespro.ru> Diagnosed-by: Arseny Sher <a.sher@postgrespro.ru> Co-authored-by: Arseny Sher <a.sher@postgrespro.ru> Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Antonin Houska <ah@cybertec.at> Discussion: https://postgr.es/m/87lgdyz1wj.fsf@ars-thinkpad
2018-06-26Add PGTYPESchar_free() to avoid cross-module problems on Windows.Thomas Munro
On Windows, it is sometimes important for corresponding malloc() and free() calls to be made from the same DLL, since some build options can result in multiple allocators being active at the same time. For that reason we already provided PQfreemem(). This commit adds a similar function for freeing string results allocated by the pgtypes library. Author: Takayuki Tsunakawa Reviewed-by: Kyotaro Horiguchi Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8AD5D6%40G01JPEXMBYT05
2018-06-26Move RecoveryLockList into a hash table.Thomas Munro
Standbys frequently need to release all locks held by a given xid. Instead of searching one big list linearly, let's create one list per xid and put them in a hash table, so we can find what we need in O(1) time. Earlier analysis and a prototype were done by David Rowley, though this isn't his patch. Back-patch all the way. Author: Thomas Munro Diagnosed-by: David Rowley, Andres Freund Reviewed-by: Andres Freund, Tom Lane, Robert Haas Discussion: https://postgr.es/m/CAEepm%3D1mL0KiQ2KJ4yuPpLGX94a4Ns_W6TL4EGRouxWibu56pA%40mail.gmail.com Discussion: https://postgr.es/m/CAKJS1f9vJ841HY%3DwonnLVbfkTWGYWdPN72VMxnArcGCjF3SywA%40mail.gmail.com
2018-06-25Address set of issues with errno handlingMichael Paquier
System calls mixed up in error code paths are causing two issues which several code paths have not correctly handled: 1) For write() calls, sometimes the system may return less bytes than what has been written without errno being set. Some paths were careful enough to consider that case, and assumed that errno should be set to ENOSPC, other calls missed that. 2) errno generated by a system call is overwritten by other system calls which may succeed once an error code path is taken, causing what is reported to the user to be incorrect. This patch uses the brute-force approach of correcting all those code paths. Some refactoring could happen in the future, but this is let as future work, which is not targeted for back-branches anyway. Author: Michael Paquier Reviewed-by: Ashutosh Sharma Discussion: https://postgr.es/m/20180622061535.GD5215@paquier.xyz
2018-06-16Avoid unnecessary use of strncpy in a couple of places in ecpg.Tom Lane
Use of strncpy with a length limit based on the source, rather than the destination, is non-idiomatic and draws warnings from gcc 8. Replace with memcpy, which does exactly the same thing in these cases, but with less chance for confusion. Backpatch to all supported branches. Discussion: https://postgr.es/m/21789.1529170195@sss.pgh.pa.us
2018-06-12Fix bugs in vacuum of shared rels, by keeping their relcache entries current.Andres Freund
When vacuum processes a relation it uses the corresponding relcache entry's relfrozenxid / relminmxid as a cutoff for when to remove tuples etc. Unfortunately for nailed relations (i.e. critical system catalogs) bugs could frequently lead to the corresponding relcache entry being stale. This set of bugs could cause actual data corruption as vacuum would potentially not remove the correct row versions, potentially reviving them at a later point. After 699bf7d05c some corruptions in this vein were prevented, but the additional error checks could also trigger spuriously. Examples of such errors are: ERROR: found xmin ... from before relfrozenxid ... and ERROR: found multixact ... from before relminmxid ... To be caused by this bug the errors have to occur on system catalog tables. The two bugs are: 1) Invalidations for nailed relations were ignored, based on the theory that the relcache entry for such tables doesn't change. Which is largely true, except for fields like relfrozenxid etc. This means that changes to relations vacuumed in other sessions weren't picked up by already existing sessions. Luckily autovacuum doesn't have particularly longrunning sessions. 2) For shared *and* nailed relations, the shared relcache init file was never invalidated while running. That means that for such tables (e.g. pg_authid, pg_database) it's not just already existing sessions that are affected, but even new connections are as well. That explains why the reports usually were about pg_authid et. al. To fix 1), revalidate the rd_rel portion of a relcache entry when invalid. This implies a bit of extra complexity to deal with bootstrapping, but it's not too bad. The fix for 2) is simpler, simply always remove both the shared and local init files. Author: Andres Freund Reviewed-By: Alvaro Herrera Discussion: https://postgr.es/m/20180525203736.crkbg36muzxrjj5e@alap3.anarazel.de https://postgr.es/m/CAMa1XUhKSJd98JW4o9StWPrfS=11bPgG+_GDMxe25TvUY4Sugg@mail.gmail.com https://postgr.es/m/CAKMFJucqbuoDRfxPDX39WhA3vJyxweRg_zDVXzncr6+5wOguWA@mail.gmail.com https://postgr.es/m/CAGewt-ujGpMLQ09gXcUFMZaZsGJC98VXHEFbF-tpPB0fB13K+A@mail.gmail.com Backpatch: 9.3-
2018-06-06Fix function code in error reportAlvaro Herrera
This bug causes a lseek() failure to be reported as a "could not open" failure in the error message, muddling bug reports. I introduced this copy-and-pasteo in commit 78e122010422. Noticed while reviewing code for bug report #15221, from lily liang. In version 10 the affected function is only used by multixact.c and commit_ts, and only in corner-case circumstances, neither of which are involved in the reported bug (a pg_subtrans failure.) Author: Álvaro Herrera
2018-05-25Fix misidentification of SQL statement type in plpgsql's exec_stmt_execsql.Tom Lane
To distinguish SQL statements that are INSERT/UPDATE/DELETE from other ones, exec_stmt_execsql looked at the post-rewrite form of the statement rather than the original. This is problematic because it did that only during first execution of the statement (in a session), but the correct answer could change later due to addition or removal of DO INSTEAD rules during the session. That could lead to an Assert failure, as reported by Tushar Ahuja and Robert Haas. In non-assert builds, there's a hazard that we would fail to enforce STRICT behavior when we'd be expected to. That would happen if an initially present DO INSTEAD, that replaced the original statement with one of a different type, were removed; after that the statement should act "normally", including strictness enforcement, but it didn't. (The converse case of enforcing strictness when we shouldn't doesn't seem to be a hazard, as addition of a DO INSTEAD that changes the statement type would always lead to acting as though the statement returned zero rows, so that the strictness error could not fire.) To fix, inspect the original form of the statement not the post-rewrite form, making it valid to assume the answer can't change intra-session. This should lead to the same answer in every case except when there is a DO INSTEAD that changes the statement type; we will now set mod_stmt=true anyway, while we would not have done so before. That breaks the Assert in the SPI_OK_REWRITTEN code path, which expected the latter behavior. It might be all right to assert mod_stmt rather than !mod_stmt there, but I'm not entirely convinced that that'd always hold, so just remove the assertion altogether. This has been broken for a long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/CA+TgmoZUrRN4xvZe_BbBn_Xp0BDwuMEue-0OyF0fJpfvU2Yc7Q@mail.gmail.com
2018-05-24Properly schema-qualify additional object types in getObjectDescription().Tom Lane
Collations, conversions, extended statistics objects (in >= v10), and all four types of text search objects have schema-qualified names. getObjectDescription() ignored that and would emit just the base name of the object, potentially producing wrong or at least highly misleading output. Fix it to add the schema name whenever the object is not "visible" in the current search path, as is the rule for other schema-qualifiable object types. Although in common situations the output won't change, this seems to me (tgl) to be a bug worthy of back-patching, hence do so. Kyotaro Horiguchi, per a complaint from me Discussion: https://postgr.es/m/20180522.182020.114074746.horiguchi.kyotaro@lab.ntt.co.jp
2018-05-23Fix simple_prompt() to disable echo on Windows when stdin != terminal.Tom Lane
If echo = false, simple_prompt() is supposed to prevent echoing the input (for password input). However, the Windows implementation applied the mode change to STD_INPUT_HANDLE. That would not have the desired effect if stdin isn't actually the terminal, for instance if the user is piping something into psql. Fix it to apply the mode change to the correct input file, so that passwords do not echo in such cases. In passing, shorten and de-uglify this code by using #elif rather than an #if nest and removing some duplicated code. Back-patch to all supported versions. To simplify that, also back-patch the portions of commit 9daec77e1 that got rid of an unnecessary malloc/free in the same area. Matthew Stickney (cosmetic changes by me) Discussion: https://postgr.es/m/502a1fff-862b-da52-1031-f68df6ed5a2d@gmail.com
2018-05-22Widen COPY FROM's current-line-number counter from 32 to 64 bits.Tom Lane
Because the code for the HEADER option skips a line when this counter is zero, a very long COPY FROM WITH HEADER operation would drop a line every 2^32 lines. A lesser but still unfortunate problem is that errors would show a wrong input line number for errors occurring beyond the 2^31'st input line. While such large input streams seemed impractical when this code was first written, they're not any more. Widening the counter (and some associated variables) to uint64 should be enough to prevent problems for the foreseeable future. David Rowley Discussion: https://postgr.es/m/CAKJS1f88yh-6wwEfO6QLEEvH3BEugOq2QX1TOja0vCauoynmOQ@mail.gmail.com
2018-05-21Fix SQL:2008 FETCH FIRST syntax to allow parameters.Andrew Gierth
OFFSET <x> ROWS FETCH FIRST <y> ROWS ONLY syntax is supposed to accept <simple value specification>, which includes parameters as well as literals. When this syntax was added all those years ago, it was done inconsistently, with <x> and <y> being different subsets of the standard syntax. Rectify that by making <x> and <y> accept the same thing, and allowing either a (signed) numeric literal or a c_expr there, which allows for parameters, variables, and parenthesized arbitrary expressions. Per bug #15200 from Lukas Eder. Backpatch all the way, since this has been broken from the start. Discussion: https://postgr.es/m/877enz476l.fsf@news-spur.riddles.org.uk Discussion: http://postgr.es/m/152647780335.27204.16895288237122418685@wrigleys.postgresql.org
2018-05-21Fix unsafe usage of strerror(errno) within ereport().Tom Lane
This is the converse of the unsafe-usage-of-%m problem: the reason ereport/elog provide that format code is mainly to dodge the hazard of errno getting changed before control reaches functions within the arguments of the macro. I only found one instance of this hazard, but it's been there since 9.4 :-(.