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* Fix issues with wide tuples being updated and REPLICA IDENTITY FULL.Andres Freund2017-08-05
| | | | | | | | | | | | | | | | | | When replica identity full is being used with a wide tuple (above 2^16 bytes after compression) it lead to errors and/or crashes during decoding because the length field used to store such tuples doesn't fit into the variable used to store the width in the WAL record. To fix, discontinue use of xl_heap_header_len.t_len when decoding the old tuple version, instead compute length of the old tuple by subtracting the new tuple's length from the record length. In newer version of postgres this issue is moot because the length is stored by the new WAL machinery, instead of a xl_heap_header_len struct. A separate commit will forward-patch the regression test. Reported-By: "anderson" Discussion: http://postgr.es/m/20170105144819.f6i5o64vfvy4bn5i@alap3.anarazel.de
* Fix concurrent locking of tuple update chainAlvaro Herrera2017-07-26
| | | | | | | | | | | | | | | | | | | If several sessions are concurrently locking a tuple update chain with nonconflicting lock modes using an old snapshot, and they all succeed, it may happen that some of them fail because of restarting the loop (due to a concurrent Xmax change) and getting an error in the subsequent pass while trying to obtain a tuple lock that they already have in some tuple version. This can only happen with very high concurrency (where a row is being both updated and FK-checked by multiple transactions concurrently), but it's been observed in the field and can have unpleasant consequences such as an FK check failing to see a tuple that definitely exists: ERROR: insert or update on table "child_table" violates foreign key constraint "fk_constraint_name" DETAIL: Key (keyid)=(123456) is not present in table "parent_table". (where the key is observably present in the table). Discussion: https://postgr.es/m/20170714210011.r25mrff4nxjhmf3g@alvherre.pgsql
* Fix potential data corruption during freezeTeodor Sigaev2017-07-06
| | | | | | | Fix oversight in 3b97e6823b94 bug fix. Bitwise AND is used instead of OR and it cleans all bits in t_infomask heap tuple field. Backpatch to 9.3
* Fix typo in commentAlvaro Herrera2017-06-22
| | | | | | | | Once upon a time, WAL pointers could be NULL, but no longer. We talk about "valid" now. Reported-by: Amit Langote Discussion: https://postgr.es/m/33e9617d-27f1-eee8-3311-e27af98eaf2b@lab.ntt.co.jp
* Fix possibility of creating a "phantom" segment after promotion.Andres Freund2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When promoting a standby just after a XLOG_SWITCH record was replayed, and next segment(s) are already are locally available (via walsender, restore_command + trigger/recovery target), that segment could accidentally be recycled onto the past of the new timeline. Later checkpointer would create a .ready file for it, assuming there was an error during creation, and it would get archived. That causes trouble if another standby is later brought up from a basebackup from before the timeline creation, because it would try to read the segment, because XLogFileReadAnyTLI just tries all possible timelines, which doesn't have valid contents. Thus replay would fail. The problem, if already occurred, can be fixed by removing the segment and/or having restore_command filter it out. The reason for the creation of such "phantom" segments was, that after an XLOG_SWITCH record the EndOfLog variable points to the beginning of the next segment, and RemoveXlogFile() used XLByteToPrevSeg(). Normally RemoveXlogFile() doing so is harmless, because the last segment will still exist preventing InstallXLogFileSegment() from causing harm, but just after promotion there's no previous segment on the new timeline. Fix that by using XLByteToSeg() instead of XLByteToPrevSeg(). Author: Andres Freund Reported-By: Greg Burek Discussion: https://postgr.es/m/20170619073026.zcwpe6mydsaz5ygd@alap3.anarazel.de Backpatch: 9.2-, bug older than all supported versions
* Prevent possibility of panics during shutdown checkpoint.Andres Freund2017-06-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the checkpointer writes the shutdown checkpoint, it checks afterwards whether any WAL has been written since it started and throws a PANIC if so. At that point, only walsenders are still active, so one might think this could not happen, but walsenders can also generate WAL, for instance in BASE_BACKUP and logical decoding related commands (e.g. via hint bits). So they can trigger this panic if such a command is run while the shutdown checkpoint is being written. To fix this, divide the walsender shutdown into two phases. First, checkpointer, itself triggered by postmaster, sends a PROCSIG_WALSND_INIT_STOPPING signal to all walsenders. If the backend is idle or runs an SQL query this causes the backend to shutdown, if logical replication is in progress all existing WAL records are processed followed by a shutdown. Otherwise this causes the walsender to switch to the "stopping" state. In this state, the walsender will reject any further replication commands. The checkpointer begins the shutdown checkpoint once all walsenders are confirmed as stopping. When the shutdown checkpoint finishes, the postmaster sends us SIGUSR2. This instructs walsender to send any outstanding WAL, including the shutdown checkpoint record, wait for it to be replicated to the standby, and then exit. Author: Andres Freund, based on an earlier patch by Michael Paquier Reported-By: Fujii Masao, Andres Freund Reviewed-By: Michael Paquier Discussion: https://postgr.es/m/20170602002912.tqlwn4gymzlxpvs2@alap3.anarazel.de Backpatch: 9.4, where logical decoding was introduced
* Fix new warnings from GCC 7Peter Eisentraut2017-05-15
| | | | | This addresses the new warning types -Wformat-truncation -Wformat-overflow that are part of -Wall, via -Wformat, in GCC 7.
* Fix order of arguments to SubTransSetParent().Tom Lane2017-04-23
| | | | | | | | | | | | | | ProcessTwoPhaseBuffer (formerly StandbyRecoverPreparedTransactions) mixed up the parent and child XIDs when calling SubTransSetParent to record the transactions' relationship in pg_subtrans. Remarkably, analysis by Simon Riggs suggests that this doesn't lead to visible problems (at least, not in non-Assert builds). That might explain why we'd not noticed it before. Nonetheless, it's surely wrong. This code was born broken, so back-patch to all supported branches. Discussion: https://postgr.es/m/20110.1492905318@sss.pgh.pa.us
* Spelling fixesPeter Eisentraut2017-03-14
| | | | From: Josh Soref <jsoref@gmail.com>
* Fix incorrect variable datatypeMagnus Hagander2017-02-28
| | | | | | | Both datatypes map to the same underlying one which is why it still worked, but we should use the correct type. Author: Kyotaro HORIGUCHI
* Fix typos in comments.Heikki Linnakangas2017-02-06
| | | | | | | | | Backpatch to all supported versions, where applicable, to make backpatching of future fixes go more smoothly. Josh Soref Discussion: https://www.postgresql.org/message-id/CACZqfqCf+5qRztLPgmmosr-B0Ye4srWzzw_mo4c_8_B_mtjmJQ@mail.gmail.com
* Fix an assertion failure related to an exclusive backup.Fujii Masao2017-01-17
| | | | | | | | | | | | | | | | | | | | | | Previously multiple sessions could execute pg_start_backup() and pg_stop_backup() to start and stop an exclusive backup at the same time. This could trigger the assertion failure of "FailedAssertion("!(XLogCtl->Insert.exclusiveBackup)". This happend because, even while pg_start_backup() was starting an exclusive backup, other session could run pg_stop_backup() concurrently and mark the backup as not-in-progress unconditionally. This patch introduces ExclusiveBackupState indicating the state of an exclusive backup. This state is used to ensure that there is only one session running pg_start_backup() or pg_stop_backup() at the same time, to avoid the assertion failure. Back-patch to all supported versions. Author: Michael Paquier Reviewed-By: Kyotaro Horiguchi and me Reported-By: Andreas Seltenreich Discussion: <87mvktojme.fsf@credativ.de>
* Remove triggerable Assert in hashname().Tom Lane2016-12-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hashname() asserted that the key string it is given is shorter than NAMEDATALEN. That should surely always be true if the input is in fact a regular value of type "name". However, for reasons of coding convenience, we allow plain old C strings to be treated as "name" values in many places. Some SQL functions accept arbitrary "text" inputs, convert them to C strings, and pass them otherwise-untransformed to syscache lookups for name columns, allowing an overlength input value to trigger hashname's Assert. This would be a DOS problem, except that it only happens in assert-enabled builds which aren't recommended for production. In a production build, you'll just get a name lookup error, since regardless of the hash value computed by hashname, the later equality comparison checks can't match. Likewise, if the catalog lookup is done by seqscan or indexscan searches, there will just be a lookup error, since the name comparison functions don't contain any similar length checks, and will see an overlength input as unequal to any stored entry. After discussion we concluded that we should simply remove this Assert. It's inessential to hashname's own functionality, and having such an assertion in only some paths for name lookup is more of a foot-gun than a useful check. There may or may not be a case for the affected callers to do something other than let the name lookup fail, but we'll consider that separately; in any case we probably don't want to change such behavior in the back branches. Per report from Tushar Ahuja. Back-patch to all supported branches. Report: https://postgr.es/m/7d0809ee-6f25-c9d6-8e74-5b2967830d49@enterprisedb.com Discussion: https://postgr.es/m/17691.1482523168@sss.pgh.pa.us
* Fix broken error check in _hash_doinsert.Robert Haas2016-12-22
| | | | | | | | | | | | You can't just cast a HashMetaPage to a Page, because the meta page data is stored after the page header, not at offset 0. Fortunately, this didn't break anything because it happens to find hashm_bsize at the offset at which it expects to find pd_pagesize_version, and the values are close enough to the same that this works out. Still, it's a bug, so back-patch to all supported versions. Mithun Cy, revised a bit by me.
* Back-patch fcff8a575198478023ada8a48e13b50f70054766 as a bug fix.Kevin Grittner2016-12-13
| | | | | | | | | | | | | | | | | When there is both a serialization failure and a unique violation, throw the former rather than the latter. When initially pushed, this was viewed as a feature to assist application framework developers, so that they could more accurately determine when to retry a failed transaction, but a test case presented by Ian Jackson has shown that this patch can prevent serialization anomalies in some cases where a unique violation is caught within a subtransaction, the work of that subtransaction is discarded, and no error is thrown. That makes this a bug fix, so it is being back-patched to all supported branches where it is not already present (i.e., 9.2 to 9.5). Discussion: https://postgr.es/m/1481307991-16971-1-git-send-email-ian.jackson@eu.citrix.com Discussion: https://postgr.es/m/22607.56276.807567.924144@mariner.uk.xensource.com
* Log the creation of an init fork unconditionally.Robert Haas2016-12-08
| | | | | | | | | | | | | | | | | Previously, it was thought that this only needed to be done for the benefit of possible standbys, so wal_level = minimal skipped it. But that's not safe, because during crash recovery we might replay XLOG_DBASE_CREATE or XLOG_TBLSPC_CREATE record which recursively removes the directory that contains the new init fork. So log it always. The user-visible effect of this bug is that if you create a database or tablespace, then create an unlogged table, then crash without checkpointing, then restart, accessing the table will fail, because the it won't have been properly reset. This commit fixes that. Michael Paquier, per a report from Konstantin Knizhnik. Wording of the comments per a suggestion from me.
* Avoid pin scan for replay of XLOG_BTREE_VACUUM in all casesAlvaro Herrera2016-11-17
| | | | | | | | | | | | | | | | | | | | | | | Replay of XLOG_BTREE_VACUUM during Hot Standby was previously thought to require complex interlocking that matched the requirements on the master. This required an O(N) operation that became a significant problem with large indexes, causing replication delays of seconds or in some cases minutes while the XLOG_BTREE_VACUUM was replayed. This commit skips the “pin scan” that was previously required, by observing in detail when and how it is safe to do so, with full documentation. The pin scan is skipped only in replay; the VACUUM code path on master is not touched here. No tests included. Manual tests using an additional patch to view WAL records and their timing have shown the change in WAL records and their handling has successfully reduced replication delay. This is a back-patch of commits 687f2cd7a015, 3e4b7d87988f, b60284261375 by Simon Riggs, to branches 9.4 and 9.5. No further backpatch is possible because this depends on catalog scans being MVCC. I (Álvaro) additionally updated a slight problem in the README, which explains why this touches the 9.6 and master branches.
* Fix possible pg_basebackup failure on standby with "include WAL".Robert Haas2016-10-27
| | | | | | | | | | | | | | | If a restartpoint flushed no dirty buffers, it could fail to update the minimum recovery point, leading to a minimum recovery point prior to the starting REDO location. perform_base_backup() would interpret that as meaning that no WAL files at all needed to be included in the backup, failing an internal sanity check. To fix, have restartpoints always update the minimum recovery point to just after the checkpoint record itself, so that the file (or files) containing the checkpoint record will always be included in the backup. Code by Amit Kapila, per a design suggestion by me, with some additional work on the code comment by me. Test case by Michael Paquier. Report by Kyotaro Horiguchi.
* Fix WAL-logging of FSM and VM truncation.Heikki Linnakangas2016-10-19
| | | | | | | | | | | | | | | | | | | | | | | | | | When a relation is truncated, it is important that the FSM is truncated as well. Otherwise, after recovery, the FSM can return a page that has been truncated away, leading to errors like: ERROR: could not read block 28991 in file "base/16390/572026": read only 0 of 8192 bytes We were using MarkBufferDirtyHint() to dirty the buffer holding the last remaining page of the FSM, but during recovery, that might in fact not dirty the page, and the FSM update might be lost. To fix, use the stronger MarkBufferDirty() function. MarkBufferDirty() requires us to do WAL-logging ourselves, to protect from a torn page, if checksumming is enabled. Also fix an oversight in visibilitymap_truncate: it also needs to WAL-log when checksumming is enabled. Analysis by Pavan Deolasee. Discussion: <CABOikdNr5vKucqyZH9s1Mh0XebLs_jRhKv6eJfNnD2wxTn=_9A@mail.gmail.com> Backpatch to 9.3, where we got data checksums.
* Fix locking a tuple updated by an aborted (sub)transactionAlvaro Herrera2016-09-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When heap_lock_tuple decides to follow the update chain, it tried to also lock any version of the tuple that was created by an update that was subsequently rolled back. This is pointless, since for all intents and purposes that tuple exists no more; and moreover it causes misbehavior, as reported independently by Marko Tiikkaja and Marti Raudsepp: some SELECT FOR UPDATE/SHARE queries may fail to return the tuples, and assertion-enabled builds crash. Fix by having heap_lock_updated_tuple test the xmin and return success immediately if the tuple was created by an aborted transaction. The condition where tuples become invisible occurs when an updated tuple chain is followed by heap_lock_updated_tuple, which reports the problem as HeapTupleSelfUpdated to its caller heap_lock_tuple, which in turn propagates that code outwards possibly leading the calling code (ExecLockRows) to believe that the tuple exists no longer. Backpatch to 9.3. Only on 9.5 and newer this leads to a visible failure, because of commit 27846f02c176; before that, heap_lock_tuple skips the whole dance when the tuple is already locked by the same transaction, because of the ancient HeapTupleSatisfiesUpdate behavior. Still, the buggy condition may also exist in more convoluted scenarios involving concurrent transactions, so it seems safer to fix the bug in the old branches too. Discussion: https://www.postgresql.org/message-id/CABRT9RC81YUf1=jsmWopcKJEro=VoeG2ou6sPwyOUTx_qteRsg@mail.gmail.com https://www.postgresql.org/message-id/48d3eade-98d3-8b9a-477e-1a8dc32a724d@joh.to
* Fix corrupt GIN_SEGMENT_ADDITEMS WAL records on big-endian hardware.Tom Lane2016-09-03
| | | | | | | | | | | | | | | | | | | | computeLeafRecompressWALData() tried to produce a uint16 WAL log field by memcpy'ing the first two bytes of an int-sized variable. That accidentally works on little-endian hardware, but not at all on big-endian. Replay then thinks it's looking at an ADDITEMS action with zero entries, and reads the first two bytes of the first TID therein as the next segno/action, typically leading to "unexpected GIN leaf action" errors during replay. Even if replay failed to crash, the resulting GIN index page would surely be incorrect. To fix, just declare the variable as uint16 instead. Per bug #14295 from Spencer Thomason (much thanks to Spencer for turning his problem into a self-contained test case). This likely also explains a previous report of the same symptom from Bernd Helmle. Back-patch to 9.4 where the problem was introduced (by commit 14d02f0bb). Discussion: <20160826072658.15676.7628@wrigleys.postgresql.org> Possible-Report: <2DA7350F7296B2A142272901@eje.land.credativ.lan>
* Prevent starting a standalone backend with standby_mode on.Tom Lane2016-08-31
| | | | | | | | | | | | | | | | | | | This can't really work because standby_mode expects there to be more WAL arriving, which there will not ever be because there's no WAL receiver process to fetch it. Moreover, if standby_mode is on then hot standby might also be turned on, causing even more strangeness because that expects read-only sessions to be executing in parallel. Bernd Helmle reported a case where btree_xlog_delete_get_latestRemovedXid got confused, but rather than band-aiding individual problems it seems best to prevent getting anywhere near this state in the first place. Back-patch to all supported branches. In passing, also fix some omissions of errcodes in other ereport's in readRecoveryCommandFile(). Michael Paquier (errcode hacking by me) Discussion: <00F0B2CEF6D0CEF8A90119D4@eje.credativ.lan>
* Fix pg_xlogdump so that it handles cross-page XLP_FIRST_IS_CONTRECORD record.Fujii Masao2016-08-29
| | | | | | | | | | | | | | | | | | Previously pg_xlogdump failed to dump the contents of the WAL file if the file starts with the continuation WAL record which spans more than one pages. Since pg_xlogdump assumed that the continuation record always fits on a page, it could not find the valid WAL record to start reading from in that case. This patch changes pg_xlogdump so that it can handle a continuation WAL record which crosses a page boundary and find the valid record to start reading from. Back-patch to 9.3 where pg_xlogdump was introduced. Author: Pavan Deolasee Reviewed-By: Michael Paquier and Craig Ringer Discussion: CABOikdPsPByMiG6J01DKq6om2+BNkxHTPkOyqHM2a4oYwGKsqQ@mail.gmail.com
* Fix small query-lifespan memory leak in bulk updates.Tom Lane2016-08-24
| | | | | | | | | | | | | When there is an identifiable REPLICA IDENTITY index on the target table, heap_update leaks the id_attrs bitmapset. That's not many bytes, but it adds up over enough rows, since the code typically runs in a query-lifespan context. Bug introduced in commit e55704d8b, which did a rather poor job of cloning the existing use-pattern for RelationGetIndexAttrBitmap(). Per bug #14293 from Zhou Digoal. Back-patch to 9.4 where the bug was introduced. Report: <20160824114320.15676.45171@wrigleys.postgresql.org>
* In B-tree page deletion, clean up properly after page deletion failure.Tom Lane2016-08-06
| | | | | | | | | | | | | | | | | | | | | | In _bt_unlink_halfdead_page(), we might fail to find an immediate left sibling of the target page, perhaps because of corruption of the page sibling links. The code intends to cope with this by just abandoning the deletion attempt; but what actually happens is that it fails outright due to releasing the same buffer lock twice. (And error recovery masks a second problem, which is possible leakage of a pin on another page.) Seems to have been introduced by careless refactoring in commit efada2b8e. Since there are multiple cases to consider, let's make releasing the buffer lock in the failure case the responsibility of _bt_unlink_halfdead_page() not its caller. Also, avoid fetching the leaf page's left-link again after we've dropped lock on the page. This is probably harmless, but it's not exactly good coding practice. Per report from Kyotaro Horiguchi. Back-patch to 9.4 where the faulty code was introduced. Discussion: <20160803.173116.111915228.horiguchi.kyotaro@lab.ntt.co.jp>
* Fix torn-page, unlogged xid and further risks from heap_update().Andres Freund2016-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When heap_update needs to look for a page for the new tuple version, because the current one doesn't have sufficient free space, or when columns have to be processed by the tuple toaster, it has to release the lock on the old page during that. Otherwise there'd be lock ordering and lock nesting issues. To avoid concurrent sessions from trying to update / delete / lock the tuple while the page's content lock is released, the tuple's xmax is set to the current session's xid. That unfortunately was done without any WAL logging, thereby violating the rule that no XIDs may appear on disk, without an according WAL record. If the database were to crash / fail over when the page level lock is released, and some activity lead to the page being written out to disk, the xid could end up being reused; potentially leading to the row becoming invisible. There might be additional risks by not having t_ctid point at the tuple itself, without having set the appropriate lock infomask fields. To fix, compute the appropriate xmax/infomask combination for locking the tuple, and perform WAL logging using the existing XLOG_HEAP_LOCK record. That allows the fix to be backpatched. This issue has existed for a long time. There appears to have been partial attempts at preventing dangers, but these never have fully been implemented, and were removed a long time ago, in 11919160 (cf. HEAP_XMAX_UNLOGGED). In master / 9.6, there's an additional issue, namely that the visibilitymap's freeze bit isn't reset at that point yet. Since that's a new issue, introduced only in a892234f830, that'll be fixed in a separate commit. Author: Masahiko Sawada and Andres Freund Reported-By: Different aspects by Thomas Munro, Noah Misch, and others Discussion: CAEepm=3fWAbWryVW9swHyLTY4sXVf0xbLvXqOwUoDiNCx9mBjQ@mail.gmail.com Backpatch: 9.1/all supported versions
* Make HEAP_LOCK/HEAP2_LOCK_UPDATED replay reset HEAP_XMAX_INVALID.Andres Freund2016-07-15
| | | | | | | | | | | | | | | 0ac5ad5 started to compress infomask bits in WAL records. Unfortunately the replay routines for XLOG_HEAP_LOCK/XLOG_HEAP2_LOCK_UPDATED forgot to reset the HEAP_XMAX_INVALID (and some other) hint bits. Luckily that's not problematic in the majority of cases, because after a crash/on a standby row locks aren't meaningful. Unfortunately that does not hold true in the presence of prepared transactions. This means that after a crash, or after promotion, row level locks held by a prepared, but not yet committed, prepared transaction might not be enforced. Discussion: 20160715192319.ubfuzim4zv3rqnxv@alap3.anarazel.de Backpatch: 9.3, the oldest branch on which 0ac5ad5 is present.
* Avoid serializability errors when locking a tuple with a committed updateAlvaro Herrera2016-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When key-share locking a tuple that has been not-key-updated, and the update is a committed transaction, in some cases we raised serializability errors: ERROR: could not serialize access due to concurrent update Because the key-share doesn't conflict with the update, the error is unnecessary and inconsistent with the case that the update hasn't committed yet. This causes problems for some usage patterns, even if it can be claimed that it's sufficient to retry the aborted transaction: given a steady stream of updating transactions and a long locking transaction, the long transaction can be starved indefinitely despite multiple retries. To fix, we recognize that HeapTupleSatisfiesUpdate can return HeapTupleUpdated when an updating transaction has committed, and that we need to deal with that case exactly as if it were a non-committed update: verify whether the two operations conflict, and if not, carry on normally. If they do conflict, however, there is a difference: in the HeapTupleBeingUpdated case we can just sleep until the concurrent transaction is gone, while in the HeapTupleUpdated case this is not possible and we must raise an error instead. Per trouble report from Olivier Dony. In addition to a couple of test cases that verify the changed behavior, I added a test case to verify the behavior that remains unchanged, namely that errors are raised when a update that modifies the key is used. That must still generate serializability errors. One pre-existing test case changes behavior; per discussion, the new behavior is actually the desired one. Discussion: https://www.postgresql.org/message-id/560AA479.4080807@odoo.com https://www.postgresql.org/message-id/20151014164844.3019.25750@wrigleys.postgresql.org Backpatch to 9.3, where the problem appeared.
* Fix GiST index build for NaN values in geometric types.Tom Lane2016-07-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GiST index build could go into an infinite loop when presented with boxes (or points, circles or polygons) containing NaN component values. This happened essentially because the code assumed that x == x is true for any "double" value x; but it's not true for NaNs. The looping behavior was not the only problem though: we also attempted to sort the items using simple double comparisons. Since NaNs violate the trichotomy law, qsort could (in principle at least) get arbitrarily confused and mess up the sorting of ordinary values as well as NaNs. And we based splitting choices on box size calculations that could produce NaNs, again resulting in undesirable behavior. To fix, replace all comparisons of doubles in this logic with float8_cmp_internal, which is NaN-aware and is careful to sort NaNs consistently, higher than any non-NaN. Also rearrange the box size calculation to not produce NaNs; instead it should produce an infinity for a box with NaN on one side and not-NaN on the other. I don't by any means claim that this solves all problems with NaNs in geometric values, but it should at least make GiST index insertion work reliably with such data. It's likely that the index search side of things still needs some work, and probably regular geometric operations too. But with this patch we're laying down a convention for how such cases ought to behave. Per bug #14238 from Guang-Dih Lei. Back-patch to 9.2; the code used before commit 7f3bd86843e5aad8 is quite different and doesn't lock up on my simple test case, nor on the submitter's dataset. Report: <20160708151747.1426.60150@wrigleys.postgresql.org> Discussion: <28685.1468246504@sss.pgh.pa.us>
* Fix handling of multixacts predating pg_upgradeAlvaro Herrera2016-06-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After pg_upgrade, it is possible that some tuples' Xmax have multixacts corresponding to the old installation; such multixacts cannot have running members anymore. In many code sites we already know not to read them and clobber them silently, but at least when VACUUM tries to freeze a multixact or determine whether one needs freezing, there's an attempt to resolve it to its member transactions by calling GetMultiXactIdMembers, and if the multixact value is "in the future" with regards to the current valid multixact range, an error like this is raised: ERROR: MultiXactId 123 has not been created yet -- apparent wraparound and vacuuming fails. Per discussion with Andrew Gierth, it is completely bogus to try to resolve multixacts coming from before a pg_upgrade, regardless of where they stand with regards to the current valid multixact range. It's possible to get from under this problem by doing SELECT FOR UPDATE of the problem tuples, but if tables are large, this is slow and tedious, so a more thorough solution is desirable. To fix, we realize that multixacts in xmax created in 9.2 and previous have a specific bit pattern that is never used in 9.3 and later (we already knew this, per comments and infomask tests sprinkled in various places, but we weren't leveraging this knowledge appropriately). Whenever the infomask of the tuple matches that bit pattern, we just ignore the multixact completely as if Xmax wasn't set; or, in the case of tuple freezing, we act as if an unwanted value is set and clobber it without decoding. This guarantees that no errors will be raised, and that the values will be progressively removed until all tables are clean. Most callers of GetMultiXactIdMembers are patched to recognize directly that the value is a removable "empty" multixact and avoid calling GetMultiXactIdMembers altogether. To avoid changing the signature of GetMultiXactIdMembers() in back branches, we keep the "allow_old" boolean flag but rename it to "from_pgupgrade"; if the flag is true, we always return an empty set instead of looking up the multixact. (I suppose we could remove the argument in the master branch, but I chose not to do so in this commit). This was broken all along, but the error-facing message appeared first because of commit 8e9a16ab8f7f and was partially fixed in a25c2b7c4db3. This fix, backpatched all the way back to 9.3, goes approximately in the same direction as a25c2b7c4db3 but should cover all cases. Bug analysis by Andrew Gierth and Álvaro Herrera. A number of public reports match this bug: https://www.postgresql.org/message-id/20140330040029.GY4582@tamriel.snowman.net https://www.postgresql.org/message-id/538F3D70.6080902@publicrelay.com https://www.postgresql.org/message-id/556439CF.7070109@pscs.co.uk https://www.postgresql.org/message-id/SG2PR06MB0760098A111C88E31BD4D96FB3540@SG2PR06MB0760.apcprd06.prod.outlook.com https://www.postgresql.org/message-id/20160615203829.5798.4594@wrigleys.postgresql.org
* Finish up XLOG_HINT renamingAlvaro Herrera2016-06-17
| | | | | | | Commit b8fd1a09f3 renamed XLOG_HINT to XLOG_FPI, but neglected two places. Backpatch to 9.3, like that commit.
* Avoid hot standby cancels from VAC FREEZEAlvaro Herrera2016-05-25
| | | | | | | | | | | | | | VACUUM FREEZE generated false cancelations of standby queries on an otherwise idle master. Caused by an off-by-one error on cutoff_xid which goes back to original commit. Analysis and report by Marco Nenciarini Bug fix by Simon Riggs This is a correct backpatch of commit 66fbcb0d2e to branches 9.1 through 9.4. That commit was backpatched to 9.0 originally, but it was immediately reverted in 9.0-9.4 because it didn't compile.
* Fix missing initialization of buffer_std field in _bt_newroot().Tom Lane2016-05-21
| | | | | | | | | | | | | | | | | | This would only have any effect if the old root page needed to have a full-page image made (ie, this was the first mod to it since a checkpoint), *and* if the byte left uninitialized chanced to contain zero. In that case the WAL code would fail to remove the "hole" from the full-page image, which would bloat the WAL log a bit but not have any effect worse than that. Found by buildfarm member skink, whose valgrind run noticed the use of an uninitialized value. Apparently timing in the regression tests is such that the triggering condition is rare, or valgrind testing would have seen this before. Oversight in commit 40dae7ec537c5619fc93ad602c62f37be786d161. This bug affects only the 9.4 branch, since in later branches refactoring of the WAL-log-creation APIs fixed it. Report: <20160521203101.jp5yxquhhkabvo56@alap3.anarazel.de>
* Fix obsolete commentAlvaro Herrera2016-05-12
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* Fix memory leak and other bugs in ginPlaceToPage() & subroutines.Tom Lane2016-04-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 36a35c550ac114ca turned the interface between ginPlaceToPage and its subroutines in gindatapage.c and ginentrypage.c into a royal mess: page-update critical sections were started in one place and finished in another place not even in the same file, and the very same subroutine might return having started a critical section or not. Subsequent patches band-aided over some of the problems with this design by making things even messier. One user-visible resulting problem is memory leaks caused by the need for the subroutines to allocate storage that would survive until ginPlaceToPage calls XLogInsert (as reported by Julien Rouhaud). This would not typically be noticeable during retail index updates. It could be visible in a GIN index build, in the form of memory consumption swelling to several times the commanded maintenance_work_mem. Another rather nasty problem is that in the internal-page-splitting code path, we would clear the child page's GIN_INCOMPLETE_SPLIT flag well before entering the critical section that it's supposed to be cleared in; a failure in between would leave the index in a corrupt state. There were also assorted coding-rule violations with little immediate consequence but possible long-term hazards, such as beginning an XLogInsert sequence before entering a critical section, or calling elog(DEBUG) inside a critical section. To fix, redefine the API between ginPlaceToPage() and its subroutines by splitting the subroutines into two parts. The "beginPlaceToPage" subroutine does what can be done outside a critical section, including full computation of the result pages into temporary storage when we're going to split the target page. The "execPlaceToPage" subroutine is called within a critical section established by ginPlaceToPage(), and it handles the actual page update in the non-split code path. The critical section, as well as the XLOG insertion call sequence, are both now always started and finished in ginPlaceToPage(). Also, make ginPlaceToPage() create and work in a short-lived memory context to eliminate the leakage problem. (Since a short-lived memory context had been getting created in the most common code path in the subroutines, this shouldn't cause any noticeable performance penalty; we're just moving the overhead up one call level.) In passing, fix a bunch of comments that had gone unmaintained throughout all this klugery. Report: <571276DD.5050303@dalibo.com>
* Fix memory leak in GIN index scans.Tom Lane2016-04-15
| | | | | | | | | | | The code had a query-lifespan memory leak when encountering GIN entries that have posting lists (rather than posting trees, ie, there are a relatively small number of heap tuples containing this index key value). With a suitable data distribution this could add up to a lot of leakage. Problem seems to have been introduced by commit 36a35c550, so back-patch to 9.4. Julien Rouhaud
* Fix typos in commentsAlvaro Herrera2016-03-15
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* Avoid unlikely data-loss scenarios due to rename() without fsync.Andres Freund2016-03-09
| | | | | | | | | | | | | | | | | | | | | Renaming a file using rename(2) is not guaranteed to be durable in face of crashes. Use the previously added durable_rename()/durable_link_or_rename() in various places where we previously just renamed files. Most of the changed call sites are arguably not critical, but it seems better to err on the side of too much durability. The most prominent known case where the previously missing fsyncs could cause data loss is crashes at the end of a checkpoint. After the actual checkpoint has been performed, old WAL files are recycled. When they're filled, their contents are fdatasynced, but we did not fsync the containing directory. An OS/hardware crash in an unfortunate moment could then end up leaving that file with its old name, but new content; WAL replay would thus not replay it. Reported-By: Tomas Vondra Author: Michael Paquier, Tomas Vondra, Andres Freund Discussion: 56583BDD.9060302@2ndquadrant.com Backpatch: All supported branches
* Fix incorrect handling of NULL index entries in indexed ROW() comparisons.Tom Lane2016-03-09
| | | | | | | | | | | | | | | | | | | | | | An index search using a row comparison such as ROW(a, b) > ROW('x', 'y') would stop upon reaching a NULL entry in the "b" column, ignoring the fact that there might be non-NULL "b" values associated with later values of "a". This happens because _bt_mark_scankey_required() marks the subsidiary scankey for "b" as required, which is just wrong: it's for a column after the one with the first inequality key (namely "a"), and thus can't be considered a required match. This bit of brain fade dates back to the very beginnings of our support for indexed ROW() comparisons, in 2006. Kind of astonishing that no one came across it before Glen Takahashi, in bug #14010. Back-patch to all supported versions. Note: the given test case doesn't actually fail in unpatched 9.1, evidently because the fix for bug #6278 (i.e., stopping at nulls in either scan direction) is required to make it fail. I'm sure I could devise a case that fails in 9.1 as well, perhaps with something involving making a cursor back up; but it doesn't seem worth the trouble.
* Ignore recovery_min_apply_delay until recovery has reached consistent stateFujii Masao2016-03-06
| | | | | | | | | | | | | | | | | | | Previously recovery_min_apply_delay was applied even before recovery had reached consistency. This could cause us to wait a long time unexpectedly for read-only connections to be allowed. It's problematic because the standby was useless during that wait time. This patch changes recovery_min_apply_delay so that it's applied once the database has reached the consistent state. That is, even if the delay is set, the standby tries to replay WAL records as fast as possible until it has reached consistency. Author: Michael Paquier Reviewed-By: Julien Rouhaud Reported-By: Greg Clough Backpatch: 9.4, where recovery_min_apply_delay was added Bug: #13770 Discussion: http://www.postgresql.org/message-id/20151111155006.2644.84564@wrigleys.postgresql.org
* Correct StartupSUBTRANS for page wraparoundSimon Riggs2016-02-19
| | | | | | | | | | StartupSUBTRANS() incorrectly handled cases near the max pageid in the subtrans data structure, which in some cases could lead to errors in startup for Hot Standby. This patch wraps the pageids correctly, avoiding any such errors. Identified by exhaustive crash testing by Jeff Janes. Jeff Janes
* Fix overly-strict assertions in spgtextproc.c.Tom Lane2016-01-02
| | | | | | | | | | | | | | | | | spg_text_inner_consistent is capable of reconstructing an empty string to pass down to the next index level; this happens if we have an empty string coming in, no prefix, and a dummy node label. (In practice, what is needed to trigger that is insertion of a whole bunch of empty-string values.) Then, we will arrive at the next level with in->level == 0 and a non-NULL (but zero length) in->reconstructedValue, which is valid but the Assert tests weren't expecting it. Per report from Andreas Seltenreich. This has no impact in non-Assert builds, so should not be a problem in production, but back-patch to all affected branches anyway. In passing, remove a couple of useless variable initializations and shorten the code by not duplicating DatumGetPointer() calls.
* Fix bug leading to restoring unlogged relations from empty files.Andres Freund2015-12-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the end of crash recovery, unlogged relations are reset to the empty state, using their init fork as the template. The init fork is copied to the main fork without going through shared buffers. Unfortunately WAL replay so far has not necessarily flushed writes from shared buffers to disk at that point. In normal crash recovery, and before the introduction of 'fast promotions' in fd4ced523 / 9.3, the END_OF_RECOVERY checkpoint flushes the buffers out in time. But with fast promotions that's not the case anymore. To fix, force WAL writes targeting the init fork to be flushed immediately (using the new FlushOneBuffer() function). In 9.5+ that flush can centrally be triggered from the code dealing with restoring full page writes (XLogReadBufferForRedoExtended), in earlier releases that responsibility is in the hands of XLOG_HEAP_NEWPAGE's replay function. Backpatch to 9.1, even if this currently is only known to trigger in 9.3+. Flushing earlier is more robust, and it is advantageous to keep the branches similar. Typical symptoms of this bug are errors like 'ERROR: index "..." contains unexpected zero page at block 0' shortly after promoting a node. Reported-By: Thom Brown Author: Andres Freund and Michael Paquier Discussion: 20150326175024.GJ451@alap3.anarazel.de Backpatch: 9.1-
* Fix serialization anomalies due to race conditions on INSERT.Kevin Grittner2015-10-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On insert the CheckForSerializableConflictIn() test was performed before the page(s) which were going to be modified had been locked (with an exclusive buffer content lock). If another process acquired a relation SIReadLock on the heap and scanned to a page on which an insert was going to occur before the page was so locked, a rw-conflict would be missed, which could allow a serialization anomaly to be missed. The window between the check and the page lock was small, so the bug was generally not noticed unless there was high concurrency with multiple processes inserting into the same table. This was reported by Peter Bailis as bug #11732, by Sean Chittenden as bug #13667, and by others. The race condition was eliminated in heap_insert() by moving the check down below the acquisition of the buffer lock, which had been the very next statement. Because of the loop locking and unlocking multiple buffers in heap_multi_insert() a check was added after all inserts were completed. The check before the start of the inserts was left because it might avoid a large amount of work to detect a serialization anomaly before performing the all of the inserts and the related WAL logging. While investigating this bug, other SSI bugs which were even harder to hit in practice were noticed and fixed, an unnecessary check (covered by another check, so redundant) was removed from heap_update(), and comments were improved. Back-patch to all supported branches. Kevin Grittner and Thomas Munro
* Re-Align *_freeze_max_age reloption limits with corresponding GUC limits.Andres Freund2015-10-05
| | | | | | | | | | | | | | In 020235a5754 I lowered the autovacuum_*freeze_max_age minimums to allow for easier testing of wraparounds. I did not touch the corresponding per-table limits. While those don't matter for the purpose of wraparound, it seems more consistent to lower them as well. It's noteworthy that the previous reloption lower limit for autovacuum_multixact_freeze_max_age was too high by one magnitude, even before 020235a5754. Discussion: 26377.1443105453@sss.pgh.pa.us Backpatch: back to 9.0 (in parts), like the prior patch
* Remove files signaling a standby promotion request at postmaster startupFujii Masao2015-09-09
| | | | | | | | | | | | | | | | | | | | | | This commit makes postmaster forcibly remove the files signaling a standby promotion request. Otherwise, the existence of those files can trigger a promotion too early, whether a user wants that or not. This removal of files is usually unnecessary because they can exist only during a few moments during a standby promotion. However there is a race condition: if pg_ctl promote is executed and creates the files during a promotion, the files can stay around even after the server is brought up to new master. Then, if new standby starts by using the backup taken from that master, the files can exist at the server startup and should be removed in order to avoid an unexpected promotion. Back-patch to 9.1 where promote signal file was introduced. Problem reported by Feike Steenbergen. Original patch by Michael Paquier, modified by me. Discussion: 20150528100705.4686.91426@wrigleys.postgresql.org
* Make GIN's cleanup pending list process interruptableTeodor Sigaev2015-09-07
| | | | | | | | | | | Cleanup process could be called by ordinary insert/update and could take a lot of time. Add vacuum_delay_point() to make this process interruptable. Under vacuum this call will also throttle a vacuum process to decrease system load, called from insert/update it will not throttle, and that reduces a latency. Backpatch for all supported branches. Jeff Janes <jeff.janes@gmail.com>
* Fix misc typos.Heikki Linnakangas2015-09-05
| | | | Oskari Saarenmaa. Backpatch to stable branches where applicable.
* Fix subtransaction cleanup after an outer-subtransaction portal fails.Tom Lane2015-09-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Formerly, we treated only portals created in the current subtransaction as having failed during subtransaction abort. However, if the error occurred while running a portal created in an outer subtransaction (ie, a cursor declared before the last savepoint), that has to be considered broken too. To allow reliable detection of which ones those are, add a bookkeeping field to struct Portal that tracks the innermost subtransaction in which each portal has actually been executed. (Without this, we'd end up failing portals containing functions that had called the subtransaction, thereby breaking plpgsql exception blocks completely.) In addition, when we fail an outer-subtransaction Portal, transfer its resources into the subtransaction's resource owner, so that they're released early in cleanup of the subxact. This fixes a problem reported by Jim Nasby in which a function executed in an outer-subtransaction cursor could cause an Assert failure or crash by referencing a relation created within the inner subtransaction. The proximate cause of the Assert failure is that AtEOSubXact_RelationCache assumed it could blow away a relcache entry without first checking that the entry had zero refcount. That was a bad idea on its own terms, so add such a check there, and to the similar coding in AtEOXact_RelationCache. This provides an independent safety measure in case there are still ways to provoke the situation despite the Portal-level changes. This has been broken since subtransactions were invented, so back-patch to all supported branches. Tom Lane and Michael Paquier
* Document that max_worker_processes must be high enough in standby.Fujii Masao2015-09-03
| | | | | | | | | The setting values of some parameters including max_worker_processes must be equal to or higher than the values on the master. However, previously max_worker_processes was not listed as such parameter in the document. So this commit adds it to that list. Back-patch to 9.4 where max_worker_processes was added.