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2021-07-29Update minimum recovery point on truncation during WAL replay of abort record.Fujii Masao
If a file is truncated, we must update minRecoveryPoint. Once a file is truncated, there's no going back; it would not be safe to stop recovery at a point earlier than that anymore. Commit 7bffc9b7bf changed xact_redo_commit() so that it updates minRecoveryPoint on truncation, but forgot to change xact_redo_abort(). Back-patch to all supported versions. Reported-by: mengjuan.cmj@alibaba-inc.com Author: Fujii Masao Reviewed-by: Heikki Linnakangas Discussion: https://postgr.es/m/b029fce3-4fac-4265-968e-16f36ff4d075.mengjuan.cmj@alibaba-inc.com
2021-07-25Make the standby server promptly handle interrupt signals.Fujii Masao
This commit changes the startup process in the standby server so that it handles the interrupt signals after waiting for wal_retrieve_retry_interval on the latch and resetting it, before entering another wait on the latch. This change causes the standby server to promptly handle interrupt signals. Otherwise, previously, there was the case where the standby needs to wait extra five seconds to shutdown when the shutdown request arrived while the startup process was waiting for wal_retrieve_retry_interval on the latch. Author: Fujii Masao, but implementation idea is from Soumyadeep Chakraborty Reviewed-by: Soumyadeep Chakraborty Discussion: https://postgr.es/m/9d7e6ab0-8a53-ddb9-63cd-289bcb25fe0e@oss.nttdata.com Per discussion of BUG #17073, back-patch to all supported versions. Discussion: https://postgr.es/m/17073-1a5fdaed0fa5d4d0@postgresql.org
2021-07-12Remove dead assignment to local variable.Heikki Linnakangas
This should have been removed in commit 7e30c186da, which split the loop into two. Only the first loop uses the 'from' variable; updating it in the second loop is bogus. It was never read after the first loop, so this was harmless and surely optimized away by the compiler, but let's be tidy. Backpatch to all supported versions. Author: Ranier Vilela Discussion: https://www.postgresql.org/message-id/CAEudQAoWq%2BAL3BnELHu7gms2GN07k-np6yLbukGaxJ1vY-zeiQ%40mail.gmail.com
2021-06-30Fix incorrect PITR message for transaction ROLLBACK PREPAREDMichael Paquier
Reaching PITR on such a transaction would cause the generation of a LOG message mentioning a transaction committed, not aborted. Oversight in 4f1b890. Author: Simon Riggs Discussion: https://postgr.es/m/CANbhV-GJ6KijeCgdOrxqMCQ+C8QiK657EMhCy4csjrPcEUFv_Q@mail.gmail.com Backpatch-through: 9.6
2021-06-17Tidy up GetMultiXactIdMembers()'s behavior on errorHeikki Linnakangas
One of the error paths left *members uninitialized. That's not a live bug, because most callers don't look at *members when the function returns -1, but let's be tidy. One caller, in heap_lock_tuple(), does "if (members != NULL) pfree(members)", but AFAICS it never passes an invalid 'multi' value so it should not reach that error case. The callers are also a bit inconsistent in their expectations. heap_lock_tuple() pfrees the 'members' array if it's not-NULL, others pfree() it if "nmembers >= 0", and others if "nmembers > 0". That's not a live bug either, because the function should never return 0, but add an Assert for that to make it more clear. I left the callers alone for now. I also moved the line where we set *nmembers. It wasn't wrong before, but I like to do that right next to the 'return' statement, to make it clear that it's always set on return. Also remove one unreachable return statement after ereport(ERROR), for brevity and for consistency with the similar if-block right after it. Author: Greg Nancarrow with the additional changes by me Backpatch-through: 9.6, all supported versions
2021-06-09Fix corner case failure of new standby to follow new primary.Robert Haas
This only happens if (1) the new standby has no WAL available locally, (2) the new standby is starting from the old timeline, (3) the promotion happened in the WAL segment from which the new standby is starting, (4) the timeline history file for the new timeline is available from the archive but the WAL files for are not (i.e. this is a race), (5) the WAL files for the new timeline are available via streaming, and (6) recovery_target_timeline='latest'. Commit ee994272ca50f70b53074f0febaec97e28f83c4e introduced this logic and was an improvement over the previous code, but it mishandled this case. If recovery_target_timeline='latest' and restore_command is set, validateRecoveryParameters() can change recoveryTargetTLI to be different from receiveTLI. If streaming is then tried afterward, expectedTLEs gets initialized with the history of the wrong timeline. It's supposed to be a list of entries explaining how to get to the target timeline, but in this case it ends up with a list of entries explaining how to get to the new standby's original timeline, which isn't right. Dilip Kumar and Robert Haas, reviewed by Kyotaro Horiguchi. Discussion: http://postgr.es/m/CAFiTN-sE-jr=LB8jQuxeqikd-Ux+jHiXyh4YDiZMPedgQKup0g@mail.gmail.com
2021-05-14Prevent infinite insertion loops in spgdoinsert().Tom Lane
Formerly we just relied on operator classes that assert longValuesOK to eventually shorten the leaf value enough to fit on an index page. That fails since the introduction of INCLUDE-column support (commit 09c1c6ab4), because the INCLUDE columns might alone take up more than a page, meaning no amount of leaf-datum compaction will get the job done. At least with spgtextproc.c, that leads to an infinite loop, since spgtextproc.c won't throw an error for not being able to shorten the leaf datum anymore. To fix without breaking cases that would otherwise work, add logic to spgdoinsert() to verify that the leaf tuple size is decreasing after each "choose" step. Some opclasses might not decrease the size on every single cycle, and in any case, alignment roundoff of the tuple size could obscure small gains. Therefore, allow up to 10 cycles without additional savings before throwing an error. (Perhaps this number will need adjustment, but it seems quite generous right now.) As long as we've developed this logic, let's back-patch it. The back branches don't have INCLUDE columns to worry about, but this seems like a good defense against possible bugs in operator classes. We already know that an infinite loop here is pretty unpleasant, so having a defense seems to outweigh the risk of breaking things. (Note that spgtextproc.c is actually the only known opclass with longValuesOK support, so that this is all moot for known non-core opclasses anyway.) Per report from Dilip Kumar. Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
2021-05-14Fix query-cancel handling in spgdoinsert().Tom Lane
Knowing that a buggy opclass could cause an infinite insertion loop, spgdoinsert() intended to allow its loop to be interrupted by query cancel. However, that never actually worked, because in iterations after the first, we'd be holding buffer lock(s) which would cause InterruptHoldoffCount to be positive, preventing servicing of the interrupt. To fix, check if an interrupt is pending, and if so fall out of the insertion loop and service the interrupt after we've released the buffers. If it was indeed a query cancel, that's the end of the matter. If it was a non-canceling interrupt reason, make use of the existing provision to retry the whole insertion. (This isn't as wasteful as it might seem, since any upper-level index tuples we already created should be usable in the next attempt.) While there's no known instance of such a bug in existing release branches, it still seems like a good idea to back-patch this to all supported branches, since the behavior is fairly nasty if a loop does happen --- not only is it uncancelable, but it will quickly consume memory to the point of an OOM failure. In any case, this code is certainly not working as intended. Per report from Dilip Kumar. Discussion: https://postgr.es/m/CAFiTN-uxP_soPhVG840tRMQTBmtA_f_Y8N51G7DKYYqDh7XN-A@mail.gmail.com
2021-05-10Fix mishandling of resjunk columns in ON CONFLICT ... UPDATE tlists.Tom Lane
It's unusual to have any resjunk columns in an ON CONFLICT ... UPDATE list, but it can happen when MULTIEXPR_SUBLINK SubPlans are present. If it happens, the ON CONFLICT UPDATE code path would end up storing tuples that include the values of the extra resjunk columns. That's fairly harmless in the short run, but if new columns are added to the table then the values would become accessible, possibly leading to malfunctions if they don't match the datatypes of the new columns. This had escaped notice through a confluence of missing sanity checks, including * There's no cross-check that a tuple presented to heap_insert or heap_update matches the table rowtype. While it's difficult to check that fully at reasonable cost, we can easily add assertions that there aren't too many columns. * The output-column-assignment cases in execExprInterp.c lacked any sanity checks on the output column numbers, which seems like an oversight considering there are plenty of assertion checks on input column numbers. Add assertions there too. * We failed to apply nodeModifyTable's ExecCheckPlanOutput() to the ON CONFLICT UPDATE tlist. That wouldn't have caught this specific error, since that function is chartered to ignore resjunk columns; but it sure seems like a bad omission now that we've seen this bug. In HEAD, the right way to fix this is to make the processing of ON CONFLICT UPDATE tlists work the same as regular UPDATE tlists now do, that is don't add "SET x = x" entries, and use ExecBuildUpdateProjection to evaluate the tlist and combine it with old values of the not-set columns. This adds a little complication to ExecBuildUpdateProjection, but allows removal of a comparable amount of now-dead code from the planner. In the back branches, the most expedient solution seems to be to (a) use an output slot for the ON CONFLICT UPDATE projection that actually matches the target table, and then (b) invent a variant of ExecBuildProjectionInfo that can be told to not store values resulting from resjunk columns, so it doesn't try to store into nonexistent columns of the output slot. (We can't simply ignore the resjunk columns altogether; they have to be evaluated for MULTIEXPR_SUBLINK to work.) This works back to v10. In 9.6, projections work much differently and we can't cheaply give them such an option. The 9.6 version of this patch works by inserting a JunkFilter when it's necessary to get rid of resjunk columns. In addition, v11 and up have the reverse problem when trying to perform ON CONFLICT UPDATE on a partitioned table. Through a further oversight, adjust_partition_tlist() discarded resjunk columns when re-ordering the ON CONFLICT UPDATE tlist to match a partition. This accidentally prevented the storing-bogus-tuples problem, but at the cost that MULTIEXPR_SUBLINK cases didn't work, typically crashing if more than one row has to be updated. Fix by preserving resjunk columns in that routine. (I failed to resist the temptation to add more assertions there too, and to do some minor code beautification.) Per report from Andres Freund. Back-patch to all supported branches. Security: CVE-2021-32028
2021-04-07Don't add non-existent pages to bitmap from BRINTomas Vondra
The code in bringetbitmap() simply added the whole matching page range to the TID bitmap, as determined by pages_per_range, even if some of the pages were beyond the end of the heap. The query then might fail with an error like this: ERROR: could not open file "base/20176/20228.2" (target block 262144): previous segment is only 131021 blocks In this case, the relation has 262093 pages (131072 and 131021 pages), but we're trying to acess block 262144, i.e. first block of the 3rd segment. At that point _mdfd_getseg() notices the preceding segment is incomplete, and fails. Hitting this in practice is rather unlikely, because: * Most indexes use power-of-two ranges, so segments and page ranges align perfectly (segment end is also a page range end). * The table size has to be just right, with the last segment being almost full - less than one page range from full segment, so that the last page range actually crosses the segment boundary. * Prefetch has to be enabled. The regular page access checks that pages are not beyond heap end, but prefetch does not. On older releases (before 12) the execution stops after hitting the first non-existent page, so the prefetch distance has to be sufficient to reach the first page in the next segment to trigger the issue. Since 12 it's enough to just have prefetch enabled, the prefetch distance does not matter. Fixed by not adding non-existent pages to the TID bitmap. Backpatch all the way back to 9.6 (BRIN indexes were introduced in 9.5, but that release is EOL). Backpatch-through: 9.6
2021-03-25Fix bug in WAL replay of COMMIT_TS_SETTS record.Fujii Masao
Previously the WAL replay of COMMIT_TS_SETTS record called TransactionTreeSetCommitTsData() with the argument write_xlog=true, which generated and wrote new COMMIT_TS_SETTS record. This should not be acceptable because it's during recovery. This commit fixes the WAL replay of COMMIT_TS_SETTS record so that it calls TransactionTreeSetCommitTsData() with write_xlog=false and doesn't generate new WAL during recovery. Back-patch to all supported branches. Reported-by: lx zou <zoulx1982@163.com> Author: Fujii Masao Reviewed-by: Alvaro Herrera Discussion: https://postgr.es/m/16931-620d0f2fdc6108f1@postgresql.org
2021-03-17Prevent buffer overrun in read_tablespace_map().Tom Lane
Robert Foggia of Trustwave reported that read_tablespace_map() fails to prevent an overrun of its on-stack input buffer. Since the tablespace map file is presumed trustworthy, this does not seem like an interesting security vulnerability, but still we should fix it just in the name of robustness. While here, document that pg_basebackup's --tablespace-mapping option doesn't work with tar-format output, because it doesn't. To make it work, we'd have to modify the tablespace_map file within the tarball sent by the server, which might be possible but I'm not volunteering. (Less-painful solutions would require changing the basebackup protocol so that the source server could adjust the map. That's not very appetizing either.)
2021-02-23Reinstate HEAP_XMAX_LOCK_ONLY|HEAP_KEYS_UPDATED as allowedAlvaro Herrera
Commit 866e24d47db1 added an assert that HEAP_XMAX_LOCK_ONLY and HEAP_KEYS_UPDATED cannot appear together, on the faulty assumption that the latter necessarily referred to an update and not a tuple lock; but that's wrong, because SELECT FOR UPDATE can use precisely that combination, as evidenced by the amcheck test case added here. Remove the Assert(), and also patch amcheck's verify_heapam.c to not complain if the combination is found. Also, out of overabundance of caution, update (across all branches) README.tuplock to be more explicit about this. Author: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Mahendra Singh Thalor <mahi6run@gmail.com> Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com> Discussion: https://postgr.es/m/20210124061758.GA11756@nol
2021-01-25Fix hypothetical bug in heap backward scansDavid Rowley
Both heapgettup() and heapgettup_pagemode() incorrectly set the first page to scan in a backward scan in which the number of pages to scan was specified by heap_setscanlimits(). The code incorrectly started the scan at the end of the relation when startBlk was 0, or otherwise at startBlk - 1, neither of which is correct when only scanning a subset of pages. The fix here checks if heap_setscanlimits() has changed the number of pages to scan and if so we set the first page to scan as the final page in the specified range during backward scans. Proper adjustment of this code was forgotten when heap_setscanlimits() was added in 7516f5259 back in 9.5. However, practice, nowhere in core code performs backward scans after having used heap_setscanlimits(), yet, it is possible an extension uses the heap functions in this way, hence backpatch. An upcoming patch does use heap_setscanlimits() with backward scans, so this must be fixed before that can go in. Author: David Rowley Discussion: https://postgr.es/m/CAApHDvpGc9h0_oVD2CtgBcxCS1N-qDYZSeBRnUh+0CWJA9cMaA@mail.gmail.com Backpatch-through: 9.5, all supported versions
2021-01-16Prevent excess SimpleLruTruncate() deletion.Noah Misch
Every core SLRU wraps around. With the exception of pg_notify, the wrap point can fall in the middle of a page. Account for this in the PagePrecedes callback specification and in SimpleLruTruncate()'s use of said callback. Update each callback implementation to fit the new specification. This changes SerialPagePrecedesLogically() from the style of asyncQueuePagePrecedes() to the style of CLOGPagePrecedes(). (Whereas pg_clog and pg_serial share a key space, pg_serial is nothing like pg_notify.) The bug fixed here has the same symptoms and user followup steps as 592a589a04bd456410b853d86bd05faa9432cbbb. Back-patch to 9.5 (all supported versions). Reviewed by Andrey Borodin and (in earlier versions) by Tom Lane. Discussion: https://postgr.es/m/20190202083822.GC32531@gust.leadboat.com
2021-01-12Fix thinko in commentAlvaro Herrera
This comment has been wrong since its introduction in commit 2c03216d8311. Author: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAD21AoAzz6qipFJBbGEaHmyWxvvNDp8httbwLR9tUQWaTjUs2Q@mail.gmail.com
2020-12-23Fix portability issues with parsing of recovery_target_xidMichael Paquier
The parsing of this parameter has been using strtoul(), which is not portable across platforms. On most Unix platforms, unsigned long has a size of 64 bits, while on Windows it is 32 bits. It is common in recovery scenarios to rely on the output of txid_current() or even the newer pg_current_xact_id() to get a transaction ID for setting up recovery_target_xid. The value returned by those functions includes the epoch in the computed result, which would cause strtoul() to fail where unsigned long has a size of 32 bits once the epoch is incremented. WAL records and 2PC data include only information about 32-bit XIDs and it is not possible to have XIDs across more than one epoch, so discarding the high bits from the transaction ID set has no impact on recovery. On the contrary, the use of strtoul() prevents a consistent behavior across platforms depending on the size of unsigned long. This commit changes the parsing of recovery_target_xid to use pg_strtouint64() instead, available down to 9.6. There is one TAP test stressing recovery with recovery_target_xid, where a tweak based on pg_reset{xlog,wal} is added to bump the XID epoch so as this change gets tested, as per an idea from Alexander Lakhin. Reported-by: Alexander Lakhin Discussion: https://postgr.es/m/16780-107fd0c0385b1035@postgresql.org Backpatch-through: 9.6
2020-11-10Fix and simplify some usages of TimestampDifference().Tom Lane
Introduce TimestampDifferenceMilliseconds() to simplify callers that would rather have the difference in milliseconds, instead of the select()-oriented seconds-and-microseconds format. This gets rid of at least one integer division per call, and it eliminates some apparently-easy-to-mess-up arithmetic. Two of these call sites were in fact wrong: * pg_prewarm's autoprewarm_main() forgot to multiply the seconds by 1000, thus ending up with a delay 1000X shorter than intended. That doesn't quite make it a busy-wait, but close. * postgres_fdw's pgfdw_get_cleanup_result() thought it needed to compute microseconds not milliseconds, thus ending up with a delay 1000X longer than intended. Somebody along the way had noticed this problem but misdiagnosed the cause, and imposed an ad-hoc 60-second limit rather than fixing the units. This was relatively harmless in context, because we don't care that much about exactly how long this delay is; still, it's wrong. There are a few more callers of TimestampDifference() that don't have a direct need for seconds-and-microseconds, but can't use TimestampDifferenceMilliseconds() either because they do need microsecond precision or because they might possibly deal with intervals long enough to overflow 32-bit milliseconds. It might be worth inventing another API to improve that, but that seems outside the scope of this patch; so those callers are untouched here. Given the fact that we are fixing some bugs, and the likelihood that future patches might want to back-patch code that uses this new API, back-patch to all supported branches. Alexey Kondratov and Tom Lane Discussion: https://postgr.es/m/3b1c053a21c07c1ed5e00be3b2b855ef@postgrespro.ru
2020-11-09In security-restricted operations, block enqueue of at-commit user code.Noah Misch
Specifically, this blocks DECLARE ... WITH HOLD and firing of deferred triggers within index expressions and materialized view queries. An attacker having permission to create non-temp objects in at least one schema could execute arbitrary SQL functions under the identity of the bootstrap superuser. One can work around the vulnerability by disabling autovacuum and not manually running ANALYZE, CLUSTER, REINDEX, CREATE INDEX, VACUUM FULL, or REFRESH MATERIALIZED VIEW. (Don't restore from pg_dump, since it runs some of those commands.) Plain VACUUM (without FULL) is safe, and all commands are fine when a trusted user owns the target object. Performance may degrade quickly under this workaround, however. Back-patch to 9.5 (all supported versions). Reviewed by Robert Haas. Reported by Etienne Stalmans. Security: CVE-2020-25695
2020-11-07Properly detoast data in brin_form_tupleTomas Vondra
brin_form_tuple failed to consider the values may be toasted, inserting the toast pointer into the index. This may easily result in index corruption, as the toast data may be deleted and cleaned up by vacuum. The cleanup however does not care about indexes, leaving invalid toast pointers behind, which triggers errors like this: ERROR: missing chunk number 0 for toast value 16433 in pg_toast_16426 A less severe consequence are inconsistent failures due to the index row being too large, depending on whether brin_form_tuple operated on plain or toasted version of the row. For example CREATE TABLE t (val TEXT); INSERT INTO t VALUES ('... long value ...') CREATE INDEX idx ON t USING brin (val); would likely succeed, as the row would likely include toast pointer. Switching the order of INSERT and CREATE INDEX would likely fail: ERROR: index row size 8712 exceeds maximum 8152 for index "idx" because this happens before the row values are toasted. The bug exists since PostgreSQL 9.5 where BRIN indexes were introduced. So backpatch all the way back. Author: Tomas Vondra Reviewed-by: Alvaro Herrera Backpatch-through: 9.5 Discussion: https://postgr.es/m/20201001184133.oq5uq75sb45pu3aw@development Discussion: https://postgr.es/m/20201104010544.zexj52mlldagzowv%40development
2020-09-24Fix missing fsync of SLRU directories.Thomas Munro
Harmonize behavior by moving reponsibility for fsyncing directories down into slru.c. In 10 and later, only the multixact directories were missed (see commit 1b02be21), and in older branches all SLRUs were missed. Back-patch to all supported releases. Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGLtsTUOScnNoSMZ-2ZLv%2BwGh01J6kAo_DM8mTRq1sKdSQ%40mail.gmail.com
2020-08-27Fix code for re-finding scan position in a multicolumn GIN index.Tom Lane
collectMatchBitmap() needs to re-find the index tuple it was previously looking at, after transiently dropping lock on the index page it's on. The tuple should still exist and be at its prior position or somewhere to the right of that, since ginvacuum never removes tuples but concurrent insertions could add one. However, there was a thinko in that logic, to the effect of expecting any inserted tuples to have the same index "attnum" as what we'd been scanning. Since there's no physical separation of tuples with different attnums, it's not terribly hard to devise scenarios where this fails, leading to transient "lost saved point in index" errors. (While I've duplicated this with manual testing, it seems impossible to make a reproducible test case with our available testing technology.) Fix by just continuing the scan when the attnum doesn't match. While here, improve the error message used if we do fail, so that it matches the wording used in btree for a similar case. collectMatchBitmap()'s posting-tree code path was previously not exercised at all by our regression tests. While I can't make a regression test that exhibits the bug, I can at least improve the code coverage here, so do that. The test case I made for this is an extension of one added by 4b754d6c1, so it only works in HEAD and v13; didn't seem worth trying hard to back-patch it. Per bug #16595 from Jesse Kinkead. This has been broken since multicolumn capability was added to GIN (commit 27cb66fdf), so back-patch to all supported branches. Discussion: https://postgr.es/m/16595-633118be8eef9ce2@postgresql.org
2020-08-15Prevent concurrent SimpleLruTruncate() for any given SLRU.Noah Misch
The SimpleLruTruncate() header comment states the new coding rule. To achieve this, add locktype "frozenid" and two LWLocks. This closes a rare opportunity for data loss, which manifested as "apparent wraparound" or "could not access status of transaction" errors. Data loss is more likely in pg_multixact, due to released branches' thin margin between multiStopLimit and multiWrapLimit. If a user's physical replication primary logged ": apparent wraparound" messages, the user should rebuild standbys of that primary regardless of symptoms. At less risk is a cluster having emitted "not accepting commands" errors or "must be vacuumed" warnings at some point. One can test a cluster for this data loss by running VACUUM FREEZE in every database. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20190218073103.GA1434723@rfd.leadboat.com
2020-08-13Handle new HOT chains in index-build table scansAlvaro Herrera
When a table is scanned by heapam_index_build_range_scan (née IndexBuildHeapScan) and the table lock being held allows concurrent data changes, it is possible for new HOT chains to sprout in a page that were unknown when the scan of a page happened. This leads to an error such as ERROR: failed to find parent tuple for heap-only tuple at (X,Y) in table "tbl" because the root tuple was not present when we first obtained the list of the page's root tuples. This can be fixed by re-obtaining the list of root tuples, if we see that a heap-only tuple appears to point to a non-existing root. This was reported by Anastasia as occurring for BRIN summarization (which exists since 9.5), but I think it could theoretically also happen with CREATE INDEX CONCURRENTLY (much older) or REINDEX CONCURRENTLY (very recent). It seems a happy coincidence that BRIN forces us to backpatch this all the way to 9.5. Reported-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru> Diagnosed-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru> Co-authored-by: Anastasia Lubennikova <a.lubennikova@postgrespro.ru> Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://postgr.es/m/602d8487-f0b2-5486-0088-0f372b2549fa@postgrespro.ru Backpatch: 9.5 - master
2020-08-12BRIN: Handle concurrent desummarization properlyAlvaro Herrera
If a page range is desummarized at just the right time concurrently with an index walk, BRIN would raise an error indicating index corruption. This is scary and unhelpful; silently returning that the page range is not summarized is sufficient reaction. This bug was introduced by commit 975ad4e602ff as additional protection against a bug whose actual fix was elsewhere. Backpatch equally. Reported-By: Anastasia Lubennikova <a.lubennikova@postgrespro.ru> Diagnosed-By: Alexander Lakhin <exclusion@gmail.com> Discussion: https://postgr.es/m/2588667e-d07d-7e10-74e2-7e1e46194491@postgrespro.ru Backpatch: 9.5 - master
2020-06-16Fix buffile.c error handling.Thomas Munro
Convert buffile.c error handling to use ereport. This fixes cases where I/O errors were indistinguishable from EOF or not reported. Also remove "%m" from error messages where errno would be bogus. While we're modifying those strings, add block numbers and short read byte counts where appropriate. Back-patch to all supported releases. Reported-by: Amit Khandekar <amitdkhan.pg@gmail.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Ibrar Ahmed <ibrar.ahmad@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGJE04G%3D8TLK0DLypT_27D9dR8F1RQgNp0jK6qR0tZGWOw%40mail.gmail.com
2020-06-08Fix locking bugs that could corrupt pg_control.Thomas Munro
The redo routines for XLOG_CHECKPOINT_{ONLINE,SHUTDOWN} must acquire ControlFileLock before modifying ControlFile->checkPointCopy, or the checkpointer could write out a control file with a bad checksum. Likewise, XLogReportParameters() must acquire ControlFileLock before modifying ControlFile and calling UpdateControlFile(). Back-patch to all supported releases. Author: Nathan Bossart <bossartn@amazon.com> Author: Fujii Masao <masao.fujii@oss.nttdata.com> Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Thomas Munro <thomas.munro@gmail.com> Discussion: https://postgr.es/m/70BF24D6-DC51-443F-B55A-95735803842A%40amazon.com
2020-05-15Avoid killing btree items that are already deadAlvaro Herrera
_bt_killitems marks btree items dead when a scan leaves the page where they live, but it does so with only share lock (to improve concurrency). This was historicall okay, since killing a dead item has no consequences. However, with the advent of data checksums and wal_log_hints, this action incurs a WAL full-page-image record of the page. Multiple concurrent processes would write the same page several times, leading to WAL bloat. The probability of this happening can be reduced by only killing items if they're not already dead, so change the code to do that. The problem could eliminated completely by having _bt_killitems upgrade to exclusive lock upon seeing a killable item, but that would reduce concurrency so it's considered a cure worse than the disease. Backpatch all the way back to 9.5, since wal_log_hints was introduced in 9.4. Author: Masahiko Sawada <masahiko.sawada@2ndquadrant.com> Discussion: https://postgr.es/m/CA+fd4k6PeRj2CkzapWNrERkja5G0-6D-YQiKfbukJV+qZGFZ_Q@mail.gmail.com
2020-05-09Prevent archive recovery from scanning non-existent WAL files.Fujii Masao
Previously when there were multiple timelines listed in the history file of the recovery target timeline, archive recovery searched all of them, starting from the newest timeline to the oldest one, to find the segment to read. That is, archive recovery had to continuously fail scanning the segment until it reached the timeline that the segment belonged to. These scans for non-existent segment could be harmful on the recovery performance especially when archival area was located on the remote storage and each scan could take a long time. To address the issue, this commit changes archive recovery so that it skips scanning the timeline that the segment to read doesn't belong to. Per discussion, back-patch to all supported versions. Author: Kyotaro Horiguchi, tweaked a bit by Fujii Masao Reviewed-by: David Steele, Pavel Suderevsky, Grigory Smolkin Discussion: https://postgr.es/m/16159-f5a34a3a04dc67e0@postgresql.org Discussion: https://postgr.es/m/20200129.120222.1476610231001551715.horikyota.ntt@gmail.com
2020-04-24Fix handling of WAL segments ready to be archived during crash recoveryMichael Paquier
78ea8b5 has fixed an issue related to the recycling of WAL segments on standbys depending on archive_mode. However, it has introduced a regression with the handling of WAL segments ready to be archived during crash recovery, causing those files to be recycled without getting archived. This commit fixes the regression by tracking in shared memory if a live cluster is either in crash recovery or archive recovery as the handling of WAL segments ready to be archived is different in both cases (those WAL segments should not be removed during crash recovery), and by using this new shared memory state to decide if a segment can be recycled or not. Previously, it was not possible to know if a cluster was in crash recovery or archive recovery as the shared state was able to track only if recovery was happening or not, leading to the problem. A set of TAP tests is added to close the gap here, making sure that WAL segments ready to be archived are correctly handled when a cluster is in archive or crash recovery with archive_mode set to "on" or "always", for both standby and primary. Reported-by: Benoît Lobréau Author: Jehan-Guillaume de Rorthais Reviewed-by: Kyotaro Horiguchi, Fujii Masao, Michael Paquier Discussion: https://postgr.es/m/20200331172229.40ee00dc@firost Backpatch-through: 9.5
2020-04-21Fix possible crash during FATAL exit from reindexing.Tom Lane
index.c supposed that it could just use a PG_TRY block to clean up the state associated with an active REINDEX operation. However, that code doesn't run if we do a FATAL exit --- for example, due to a SIGTERM shutdown signal --- while the REINDEX is happening. And that state does get consulted during catalog accesses, which makes it problematic if we do any catalog accesses during shutdown --- for example, to clean up any temp tables created in the session. If this combination of circumstances occurred, we could find ourselves trying to access already-freed memory. In debug builds that'd fairly reliably cause an assertion failure. In production we might often get away with it, but with some bad luck it could cause a core dump. Another possible bad outcome is an erroneous conclusion that an index-to-be-accessed is being reindexed; but it looks like that would be unlikely to have any consequences worse than failing to drop temp tables right away. (They'd still get dropped by the next session that uses that temp schema.) To fix, get rid of the use of PG_TRY here, and instead hook into the transaction abort mechanisms to clean up reindex state. Per bug #16378 from Alexander Lakhin. This has been wrong for a very long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/16378-7a70ca41b3ec2009@postgresql.org
2020-04-05Use TransactionXmin instead of RecentGlobalXmin in heap_abort_speculative().Andres Freund
There's a very low risk that RecentGlobalXmin could be far enough in the past to be older than relfrozenxid, or even wrapped around. Luckily the consequences of that having happened wouldn't be too bad - the page wouldn't be pruned for a while. Avoid that risk by using TransactionXmin instead. As that's announced via MyPgXact->xmin, it is protected against wrapping around (see code comments for details around relfrozenxid). Author: Andres Freund Discussion: https://postgr.es/m/20200328213023.s4eyijhdosuc4vcj@alap3.anarazel.de Backpatch: 9.5-
2020-04-03Fix bugs in gin_fuzzy_search_limit processing.Tom Lane
entryGetItem()'s three code paths each contained bugs associated with filtering the entries for gin_fuzzy_search_limit. The posting-tree path failed to advance "advancePast" after having decided to filter an item. If we ran out of items on the current page and needed to advance to the next, what would actually happen is that entryLoadMoreItems() would re-load the same page. Eventually, the random dropItem() test would accept one of the same items it'd previously rejected, and we'd move on --- but it could take awhile with small gin_fuzzy_search_limit. To add insult to injury, this case would inevitably cause entryLoadMoreItems() to decide it needed to re-descend from the root, making things even slower. The posting-list path failed to implement gin_fuzzy_search_limit filtering at all, so that all entries in the posting list would be returned. The bitmap-result path used a "gotitem" variable that it failed to update in the one place where it'd actually make a difference, ie at the one "continue" statement. I think this was unreachable in practice, because if we'd looped around then it shouldn't be the case that the entries on the new page are before advancePast. Still, the "gotitem" variable was contributing nothing to either clarity or correctness, so get rid of it. Refactor all three loops so that the termination conditions are more alike and less unreadable. The code coverage report showed that we had no coverage at all for the re-descend-from-root code path in entryLoadMoreItems(), which seems like a very bad thing, so add a test case that exercises it. We also had exactly no coverage for gin_fuzzy_search_limit, so add a simplistic test case that at least hits those code paths a little bit. Back-patch to all supported branches. Adé Heyward and Tom Lane Discussion: https://postgr.es/m/CAEknJCdS-dE1Heddptm7ay2xTbSeADbkaQ8bU2AXRCVC2LdtKQ@mail.gmail.com
2020-03-22Revert "Skip WAL for new relfilenodes, under wal_level=minimal."Noah Misch
This reverts commit cb2fd7eac285b1b0a24eeb2b8ed4456b66c5a09f. Per numerous buildfarm members, it was incompatible with parallel query, and a test case assumed LP64. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20200321224920.GB1763544@rfd.leadboat.com
2020-03-21Skip WAL for new relfilenodes, under wal_level=minimal.Noah Misch
Until now, only selected bulk operations (e.g. COPY) did this. If a given relfilenode received both a WAL-skipping COPY and a WAL-logged operation (e.g. INSERT), recovery could lose tuples from the COPY. See src/backend/access/transam/README section "Skipping WAL for New RelFileNode" for the new coding rules. Maintainers of table access methods should examine that section. To maintain data durability, just before commit, we choose between an fsync of the relfilenode and copying its contents to WAL. A new GUC, wal_skip_threshold, guides that choice. If this change slows a workload that creates small, permanent relfilenodes under wal_level=minimal, try adjusting wal_skip_threshold. Users setting a timeout on COMMIT may need to adjust that timeout, and log_min_duration_statement analysis will reflect time consumption moving to COMMIT from commands like COPY. Internally, this requires a reliable determination of whether RollbackAndReleaseCurrentSubTransaction() would unlink a relation's current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the specification of rd_createSubid such that the field is zero when a new rel has an old rd_node. Make relcache.c retain entries for certain dropped relations until end of transaction. Back-patch to 9.5 (all supported versions). This introduces a new WAL record type, XLOG_GIST_ASSIGN_LSN, without bumping XLOG_PAGE_MAGIC. As always, update standby systems before master systems. This changes sizeof(RelationData) and sizeof(IndexStmt), breaking binary compatibility for affected extensions. (The most recent commit to affect the same class of extensions was 089e4d405d0f3b94c74a2c6a54357a84a681754b.) Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert Haas. Heikki Linnakangas and Michael Paquier implemented earlier designs that materially clarified the problem. Reviewed, in earlier designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane, Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout. Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-03-21Back-patch log_newpage_range().Noah Misch
Back-patch a subset of commit 9155580fd5fc2a0cbb23376dfca7cd21f59c2c7b to v11, v10, 9.6, and 9.5. Include the latest repairs to this function. Use a new XLOG_FPI_MULTI value instead of reusing XLOG_FPI. That way, if an older server reads WAL from this function, that server will PANIC instead of applying just one page of the record. The next commit adds a call to this function. Discussion: https://postgr.es/m/20200304.162919.898938381201316571.horikyota.ntt@gmail.com
2020-03-21During heap rebuild, lock any TOAST index until end of transaction.Noah Misch
swap_relation_files() calls toast_get_valid_index() to find and lock this index, just before swapping with the rebuilt TOAST index. The latter function releases the lock before returning. Potential for mischief is low; a concurrent session can issue ALTER INDEX ... SET (fillfactor = ...), which is not alarming. Nonetheless, changing pg_class.relfilenode without a lock is unconventional. Back-patch to 9.5 (all supported versions), because another fix needs this. Discussion: https://postgr.es/m/20191226001521.GA1772687@rfd.leadboat.com
2020-03-09Avoid assertion failure with targeted recovery in standby mode.Fujii Masao
At the end of recovery, standby mode is turned off to re-fetch the last valid record from archive or pg_wal. Previously, if recovery target was reached and standby mode was turned off while the current WAL source was stream, recovery could try to retrieve WAL file containing the last valid record unexpectedly from stream even though not in standby mode. This caused an assertion failure. That is, the assertion test confirms that WAL file should not be retrieved from stream if standby mode is not true. This commit moves back the current WAL source to archive if it's stream even though not in standby mode, to avoid that assertion failure. This issue doesn't cause the server to crash when built with assertion disabled. In this case, the attempt to retrieve WAL file from stream not in standby mode just fails. And then recovery tries to retrieve WAL file from archive or pg_wal. Back-patch to all supported branches. Author: Kyotaro Horiguchi Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/20200227.124830.2197604521555566121.horikyota.ntt@gmail.com
2020-01-20Fix crash in BRIN inclusion op functions, due to missing datum copy.Heikki Linnakangas
The BRIN add_value() and union() functions need to make a longer-lived copy of the argument, if they want to store it in the BrinValues struct also passed as argument. The functions for the "inclusion operator classes" used with box, range and inet types didn't take into account that the union helper function might return its argument as is, without making a copy. Check for that case, and make a copy if necessary. That case arises at least with the range_union() function, when one of the arguments is an 'empty' range: CREATE TABLE brintest (n numrange); CREATE INDEX brinidx ON brintest USING brin (n); INSERT INTO brintest VALUES ('empty'); INSERT INTO brintest VALUES (numrange(0, 2^1000::numeric)); INSERT INTO brintest VALUES ('(-1, 0)'); SELECT brin_desummarize_range('brinidx', 0); SELECT brin_summarize_range('brinidx', 0); Backpatch down to 9.5, where BRIN was introduced. Discussion: https://www.postgresql.org/message-id/e6e1d6eb-0a67-36aa-e779-bcca59167c14%40iki.fi Reviewed-by: Emre Hasegeli, Tom Lane, Alvaro Herrera
2019-11-24Avoid assertion failure with LISTEN in a serializable transaction.Tom Lane
If LISTEN is the only action in a serializable-mode transaction, and the session was not previously listening, and the notify queue is not empty, predicate.c reported an assertion failure. That happened because we'd acquire the transaction's initial snapshot during PreCommit_Notify, which was called *after* predicate.c expects any such snapshot to have been established. To fix, just swap the order of the PreCommit_Notify and PreCommit_CheckForSerializationFailure calls during CommitTransaction. This will imply holding the notify-insertion lock slightly longer, but the difference could only be meaningful in serializable mode, which is an expensive option anyway. It appears that this is just an assertion failure, with no consequences in non-assert builds. A snapshot used only to scan the notify queue could not have been involved in any serialization conflicts, so there would be nothing for PreCommit_CheckForSerializationFailure to do except assign it a prepareSeqNo and set the SXACT_FLAG_PREPARED flag. And given no conflicts, neither of those omissions affect the behavior of ReleasePredicateLocks. This admittedly once-over-lightly analysis is backed up by the lack of field reports of trouble. Per report from Mark Dilger. The bug is old, so back-patch to all supported branches; but the new test case only goes back to 9.6, for lack of adequate isolationtester infrastructure before that. Discussion: https://postgr.es/m/3ac7f397-4d5f-be8e-f354-440020675694@gmail.com Discussion: https://postgr.es/m/13881.1574557302@sss.pgh.pa.us
2019-11-20Revise GIN READMEAlexander Korotkov
We find GIN concurrency bugs from time to time. One of the problems here is that concurrency of GIN isn't well-documented in README. So, it might be even hard to distinguish design bugs from implementation bugs. This commit revised concurrency section in GIN README providing more details. Some examples are illustrated in ASCII art. Also, this commit add the explanation of how is tuple layout in internal GIN B-tree page different in comparison with nbtree. Discussion: https://postgr.es/m/CAPpHfduXR_ywyaVN4%2BOYEGaw%3DcPLzWX6RxYLBncKw8de9vOkqw%40mail.gmail.com Author: Alexander Korotkov Reviewed-by: Peter Geoghegan Backpatch-through: 9.4
2019-11-19Fix traversing to the deleted GIN page via downlinkAlexander Korotkov
Current GIN code appears to don't handle traversing to the deleted page via downlink. This commit fixes that by stepping right from the delete page like we do in nbtree. This commit also fixes setting 'deleted' flag to the GIN pages. Now other page flags are not erased once page is deleted. That helps to keep our assertions true if we arrive deleted page via downlink. Discussion: https://postgr.es/m/CAPpHfdvMvsw-NcE5bRS7R1BbvA4BxoDnVVjkXC5W0Czvy9LVrg%40mail.gmail.com Author: Alexander Korotkov Reviewed-by: Peter Geoghegan Backpatch-through: 9.4
2019-11-07Fix assertion failure when running pgbench -s.Fujii Masao
If there is the WAL page that the continuation WAL record just fits within (i.e., the continuation record ends just at the end of the page) and the LSN in such page is specified with -s option, previously pg_waldump caused an assertion failure. The cause of this assertion failure was that XLogFindNextRecord() that pg_waldump -s calls mistakenly handled such special WAL page. This commit changes XLogFindNextRecord() so that it can handle such WAL page correctly. Back-patch to all supported versions. Author: Andrey Lepikhov Reviewed-by: Fujii Masao, Michael Paquier Discussion: https://postgr.es/m/99303554-5dd5-06e6-f943-b3005ccd6edd@postgrespro.ru
2019-10-18Fix failure of archive recovery with recovery_min_apply_delay enabled.Fujii Masao
recovery_min_apply_delay parameter is intended for use with streaming replication deployments. However, the document clearly explains that the parameter will be honored in all cases if it's specified. So it should take effect even if in archive recovery. But, previously, archive recovery with recovery_min_apply_delay enabled always failed, and caused assertion failure if --enable-caasert is enabled. The cause of this problem is that; the ownership of recoveryWakeupLatch that recovery_min_apply_delay uses was taken only when standby mode is requested. So unowned latch could be used in archive recovery, and which caused the failure. This commit changes recovery code so that the ownership of recoveryWakeupLatch is taken even in archive recovery. Which prevents archive recovery with recovery_min_apply_delay from failing. Back-patch to v9.4 where recovery_min_apply_delay was added. Author: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CAHGQGwEyD6HdZLfdWc+95g=VQFPR4zQL4n+yHxQgGEGjaSVheQ@mail.gmail.com
2019-10-09Flush logical mapping files with fd opened for read/write at checkpointMichael Paquier
The file descriptor was opened with read-only to fsync a regular file, which would cause EBADFD errors on some platforms. This is similar to the recent fix done by a586cc4b (which was broken by me with 82a5649), except that I noticed this issue while monitoring the backend code for similar mistakes. Backpatch to 9.4, as this has been introduced since logical decoding exists as of b89e151. Author: Michael Paquier Reviewed-by: Andres Freund Discussion: https://postgr.es/m/20191006045548.GA14532@paquier.xyz Backpatch-through: 9.4
2019-10-02Remove temporary WAL and history files at the end of archive recoveryMichael Paquier
cbc55da has reworked the order of some actions at the end of archive recovery. Unfortunately this overlooked the fact that the startup process needs to remove RECOVERYXLOG (for temporary WAL segment newly recovered from archives) and RECOVERYHISTORY (for temporary history file) at this step, leaving the files around even after recovery ended. Backpatch to 9.5, like the previous commit. Author: Sawada Masahiko Reviewed-by: Fujii Masao, Michael Paquier Discussion: https://postgr.es/m/CAD21AoBO_eDQub6zojFnWtnmutRBWvYf7=cW4Hsqj+U_R26w3Q@mail.gmail.com Backpatch-through: 9.5
2019-09-25Fix failure with lock mode used for custom relation optionsMichael Paquier
In-core relation options can use a custom lock mode since 47167b7, that has lowered the lock available for some autovacuum parameters. However it forgot to consider custom relation options. This causes failures with ALTER TABLE SET when changing a custom relation option, as its lock is not defined. The existing APIs to define a custom reloption does not allow to define a custom lock mode, so enforce its initialization to AccessExclusiveMode which should be safe enough in all cases. An upcoming patch will extend the existing APIs to allow a custom lock mode to be defined. The problem can be reproduced with bloom indexes, so add a test there. Reported-by: Nikolay Sharplov Analyzed-by: Thomas Munro, Michael Paquier Author: Michael Paquier Reviewed-by: Kuntal Ghosh Discussion: https://postgr.es/m/20190920013831.GD1844@paquier.xyz Backpatch-through: 9.6
2019-09-19Fix oversight in backpatch of 6cae9d2c10Alexander Korotkov
During backpatch of 6cae9d2c10 Float8GetDatum() was accidentally removed. This commit turns it back. Reported-by: Erik Rijkers Discussion: https://postgr.es/m/6d51305e1159241cabee132f7efc7eff%40xs4all.nl Author: Tom Lane Backpatch-through: from 11 to 9.5
2019-09-19Improve handling of NULLs in KNN-GiST and KNN-SP-GiSTAlexander Korotkov
This commit improves subject in two ways: * It removes ugliness of 02f90879e7, which stores distance values and null flags in two separate arrays after GISTSearchItem struct. Instead we pack both distance value and null flag in IndexOrderByDistance struct. Alignment overhead should be negligible, because we typically deal with at most few "col op const" expressions in ORDER BY clause. * It fixes handling of "col op NULL" expression in KNN-SP-GiST. Now, these expression are not passed to support functions, which can't deal with them. Instead, NULL result is implicitly assumed. It future we may decide to teach support functions to deal with NULL arguments, but current solution is bugfix suitable for backpatch. Reported-by: Nikita Glukhov Discussion: https://postgr.es/m/826f57ee-afc7-8977-c44c-6111d18b02ec%40postgrespro.ru Author: Nikita Glukhov Reviewed-by: Alexander Korotkov Backpatch-through: 9.4
2019-09-12Fix nbtree page split rmgr desc routine.Peter Geoghegan
Include newitemoff in rmgr desc output for nbtree page split records. In passing, correct an obsolete comment that claimed that newitemoff is only logged for _L variant nbtree page split WAL records. Both issues were oversights in commit 2c03216d831, which revamped the WAL format. Author: Peter Geoghegan Backpatch: 9.5-, where the WAL format was revamped.