f5d9212e53
If temp tables have dependencies (such as sequences) then it's possible for autovacuum's cleanup of orphan temp tables to deadlock against an incoming backend that's trying to clean out the temp namespace for its own use. That can happen because RemoveTempRelations' performDeletion call can visit objects within the namespace in an order different from the order in which a per-table deletion will visit them. To fix, observe that performDeletion will begin by taking an exclusive lock on the temp namespace (even though it won't actually delete it). So, if we can get a shared lock on the namespace, we can be sure we're not running concurrently with RemoveTempRelations, while also not conflicting with ordinary use of the namespace. This requires introducing a conditional version of LockDatabaseObject, but that's no big deal. (It's surprising we've got along without that this long.) Report and patch by Mikhail Zhilin. Back-patch to all supported branches. Discussion: https://postgr.es/m/c43ce028-2bc2-4865-9b89-3f706246eed5@postgrespro.ru |
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| config | ||
| contrib | ||
| doc | ||
| src | ||
| .dir-locals.el | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| GNUmakefile.in | ||
| HISTORY | ||
| Makefile | ||
| README | ||
| README.git | ||
| aclocal.m4 | ||
| configure | ||
| configure.in | ||
README
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.