commit : 7c055f3ec3bd338a1ebb8c73cff3d01df626471e author : Tom Lane <email@example.com> date : Tue, 9 Jun 2015 15:29:38 -0400 committer: Tom Lane <firstname.lastname@example.org> date : Tue, 9 Jun 2015 15:29:38 -0400
Release notes for 9.4.4, 9.3.9, 9.2.13, 9.1.18, 9.0.22.
commit : 57ec3db2678ef826c9767003881f65e5b24bd2f2 author : Tom Lane <email@example.com> date : Tue, 9 Jun 2015 14:33:43 -0400 committer: Tom Lane <firstname.lastname@example.org> date : Tue, 9 Jun 2015 14:33:43 -0400
Report more information if pg_perm_setlocale() fails at startup.
commit : abdeb3504d079eb622264c248a0eff4a86d2614e author : Tom Lane <email@example.com> date : Tue, 9 Jun 2015 13:37:08 -0400 committer: Tom Lane <firstname.lastname@example.org> date : Tue, 9 Jun 2015 13:37:08 -0400
We don't know why a few Windows users have seen this fail, but the taciturnity of the error message certainly isn't helping debug it. Let's at least find out which LC category isn't working.
Allow HotStandbyActiveInReplay() to be called in single user mode.
commit : 0db10d4e92b655dbb3cb3a08830783107e5f9e60 author : Andres Freund <email@example.com> date : Mon, 8 Jun 2015 00:30:26 +0200 committer: Andres Freund <firstname.lastname@example.org> date : Mon, 8 Jun 2015 00:30:26 +0200
HotStandbyActiveInReplay, introduced in 061b079f, only allowed WAL replay to happen in the startup process, missing the single user case. This buglet is fairly harmless as it only causes problems when single user mode in an assertion enabled build is used to replay a btree vacuum record. Backpatch to 9.2. 061b079f was backpatched further, but the assertion was not.
Use a safer method for determining whether relcache init file is stale.
commit : be25a08a9140c9641e8c49780cebdd9e1cf3ad28 author : Tom Lane <email@example.com> date : Sun, 7 Jun 2015 15:32:09 -0400 committer: Tom Lane <firstname.lastname@example.org> date : Sun, 7 Jun 2015 15:32:09 -0400
When we invalidate the relcache entry for a system catalog or index, we must also delete the relcache "init file" if the init file contains a copy of that rel's entry. The old way of doing this relied on a specially maintained list of the OIDs of relations present in the init file: we made the list either when reading the file in, or when writing the file out. The problem is that when writing the file out, we included only rels present in our local relcache, which might have already suffered some deletions due to relcache inval events. In such cases we correctly decided not to overwrite the real init file with incomplete data --- but we still used the incomplete initFileRelationIds list for the rest of the current session. This could result in wrong decisions about whether the session's own actions require deletion of the init file, potentially allowing an init file created by some other concurrent session to be left around even though it's been made stale. Since we don't support changing the schema of a system catalog at runtime, the only likely scenario in which this would cause a problem in the field involves a "vacuum full" on a catalog concurrently with other activity, and even then it's far from easy to provoke. Remarkably, this has been broken since 2002 (in commit 786340441706ac1957a031f11ad1c2e5b6e18314), but we had never seen a reproducible test case until recently. If it did happen in the field, the symptoms would probably involve unexpected "cache lookup failed" errors to begin with, then "could not open file" failures after the next checkpoint, as all accesses to the affected catalog stopped working. Recovery would require manually removing the stale "pg_internal.init" file. To fix, get rid of the initFileRelationIds list, and instead consult syscache.c's list of relations used in catalog caches to decide whether a relation is included in the init file. This should be a tad more efficient anyway, since we're replacing linear search of a list with ~100 entries with a binary search. It's a bit ugly that the init file contents are now so directly tied to the catalog caches, but in practice that won't make much difference. Back-patch to all supported branches.
Fix incorrect order of database-locking operations in InitPostgres().
commit : 247263dc339792c7f705d1db67b640e998ed8516 author : Tom Lane <email@example.com> date : Fri, 5 Jun 2015 13:22:27 -0400 committer: Tom Lane <firstname.lastname@example.org> date : Fri, 5 Jun 2015 13:22:27 -0400
We should set MyProc->databaseId after acquiring the per-database lock, not beforehand. The old way risked deadlock against processes trying to copy or delete the target database, since they would first acquire the lock and then wait for processes with matching databaseId to exit; that left a window wherein an incoming process could set its databaseId and then block on the lock, while the other process had the lock and waited in vain for the incoming process to exit. CountOtherDBBackends() would time out and fail after 5 seconds, so this just resulted in an unexpected failure not a permanent lockup, but it's still annoying when it happens. A real-world example of a use-case is that short-duration connections to a template database should not cause CREATE DATABASE to fail. Doing it in the other order should be fine since the contract has always been that processes searching the ProcArray for a database ID must hold the relevant per-database lock while searching. Thus, this actually removes the former race condition that required an assumption that storing to MyProc->databaseId is atomic. It's been like this for a long time, so back-patch to all active branches.
Cope with possible failure of the oldest MultiXact to exist.
commit : b6a3444fa63519a0192447b8f9a332dddc66018f author : Robert Haas <email@example.com> date : Fri, 5 Jun 2015 08:34:52 -0400 committer: Robert Haas <firstname.lastname@example.org> date : Fri, 5 Jun 2015 08:34:52 -0400
Recent commits, mainly b69bf30b9bfacafc733a9ba77c9587cf54d06c0c and 53bb309d2d5a9432d2602c93ed18e58bd2924e15, introduced mechanisms to protect against wraparound of the MultiXact member space: the number of multixacts that can exist at one time is limited to 2^32, but the total number of members in those multixacts is also limited to 2^32, and older code did not take care to enforce the second limit, potentially allowing old data to be overwritten while it was still needed. Unfortunately, these new mechanisms failed to account for the fact that the code paths in which they run might be executed during recovery or while the cluster was in an inconsistent state. Also, they failed to account for the fact that users who used pg_upgrade to upgrade a PostgreSQL version between 9.3.0 and 9.3.4 might have might oldestMultiXid = 1 in the control file despite the true value being larger. To fix these problems, first, avoid unnecessarily examining the mmembers of MultiXacts when the cluster is not known to be consistent. TruncateMultiXact has done this for a long time, and this patch does not fix that. But the new calls used to prevent member wraparound are not needed until we reach normal running, so avoid calling them earlier. (SetMultiXactIdLimit is actually called before InRecovery is set, so we can't rely on that; we invent our own multixact-specific flag instead.) Second, make failure to look up the members of a MultiXact a non-fatal error. Instead, if we're unable to determine the member offset at which wraparound would occur, postpone arming the member wraparound defenses until we are able to do so. If we're unable to determine the member offset that should force autovacuum, force it continuously until we are able to do so. If we're unable to deterine the member offset at which we should truncate the members SLRU, log a message and skip truncation. An important consequence of these changes is that anyone who does have a bogus oldestMultiXid = 1 value in pg_control will experience immediate emergency autovacuuming when upgrading to a release that contains this fix. The release notes should highlight this fact. If a user has no pg_multixact/offsets/0000 file, but has oldestMultiXid = 1 in the control file, they may wish to vacuum any tables with relminmxid = 1 prior to upgrading in order to avoid an immediate emergency autovacuum after the upgrade. This must be done with a PostgreSQL version 9.3.5 or newer and with vacuum_multixact_freeze_min_age and vacuum_multixact_freeze_table_age set to 0. This patch also adds an additional log message at each database server startup, indicating either that protections against member wraparound have been engaged, or that they have not. In the latter case, once autovacuum has advanced oldestMultiXid to a sane value, the message indicating that the guards have been engaged will appear at the next checkpoint. A few additional messages have also been added at the DEBUG1 level so that the correct operation of this code can be properly audited. Along the way, this patch fixes another, related bug in TruncateMultiXact that has existed since PostgreSQL 9.3.0: when no MultiXacts exist at all, the truncation code looks up NextMultiXactId, which doesn't exist yet. This can lead to TruncateMultiXact removing every file in pg_multixact/offsets instead of keeping one around, as it should. This in turn will cause the database server to refuse to start afterwards. Patch by me. Review by Álvaro Herrera, Andres Freund, Noah Misch, and Thomas Munro.
pgindent run on access/transam/multixact.c
commit : b37f74868d2dc8bc419c6041aada338c0d74e814 author : Alvaro Herrera <email@example.com> date : Thu, 4 Jun 2015 15:20:28 -0300 committer: Alvaro Herrera <firstname.lastname@example.org> date : Thu, 4 Jun 2015 15:20:28 -0300
This file has been patched over and over, and the differences to master caused by pgindent are annoying enough that it seems saner to make the older branches look the same. Backpatch to 9.3, which is as far back as backpatching of bugfixes is necessary.
Fix some issues in pg_class.relminmxid and pg_database.datminmxid documentation.
commit : 290fb74794293e008f10f8a7501ae2e9f3969fce author : Fujii Masao <email@example.com> date : Thu, 4 Jun 2015 13:22:49 +0900 committer: Fujii Masao <firstname.lastname@example.org> date : Thu, 4 Jun 2015 13:22:49 +0900
- Correct the name of directory which those catalog columns allow to be shrunk. - Correct the name of symbol which is used as the value of pg_class.relminmxid when the relation is not a table. - Fix "ID ID" typo. Backpatch to 9.3 where those cataog columns were introduced.
Fix planner's cost estimation for SEMI/ANTI joins with inner indexscans.
commit : f0a8515c449bd3c507e71c110c695a416f9d5e08 author : Tom Lane <email@example.com> date : Wed, 3 Jun 2015 11:58:47 -0400 committer: Tom Lane <firstname.lastname@example.org> date : Wed, 3 Jun 2015 11:58:47 -0400
When the inner side of a nestloop SEMI or ANTI join is an indexscan that uses all the join clauses as indexquals, it can be presumed that both matched and unmatched outer rows will be processed very quickly: for matched rows, we'll stop after fetching one row from the indexscan, while for unmatched rows we'll have an indexscan that finds no matching index entries, which should also be quick. The planner already knew about this, but it was nonetheless charging for at least one full run of the inner indexscan, as a consequence of concerns about the behavior of materialized inner scans --- but those concerns don't apply in the fast case. If the inner side has low cardinality (many matching rows) this could make an indexscan plan look far more expensive than it actually is. To fix, rearrange the work in initial_cost_nestloop/final_cost_nestloop so that we don't add the inner scan cost until we've inspected the indexquals, and then we can add either the full-run cost or just the first tuple's cost as appropriate. Experimentation with this fix uncovered another problem: add_path and friends were coded to disregard cheap startup cost when considering parameterized paths. That's usually okay (and desirable, because it thins the path herd faster); but in this fast case for SEMI/ANTI joins, it could result in throwing away the desired plain indexscan path in favor of a bitmap scan path before we ever get to the join costing logic. In the many-matching-rows cases of interest here, a bitmap scan will do a lot more work than required, so this is a problem. To fix, add a per-relation flag consider_param_startup that works like the existing consider_startup flag, but applies to parameterized paths, and set it for relations that are the inside of a SEMI or ANTI join. To make this patch reasonably safe to back-patch, care has been taken to avoid changing the planner's behavior except in the very narrow case of SEMI/ANTI joins with inner indexscans. There are places in compare_path_costs_fuzzily and add_path_precheck that are not terribly consistent with the new approach, but changing them will affect planner decisions at the margins in other cases, so we'll leave that for a HEAD-only fix. Back-patch to 9.3; before that, the consider_startup flag didn't exist, meaning that the second aspect of the patch would be too invasive. Per a complaint from Peter Holzer and analysis by Tomas Vondra.