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Michael Paquier 246a6c8f7b Make autovacuum more aggressive to remove orphaned temp tables
Commit dafa084, added in 10, made the removal of temporary orphaned
tables more aggressive.  This commit makes an extra step into the
aggressiveness by adding a flag in each backend's MyProc which tracks
down any temporary namespace currently in use.  The flag is set when the
namespace gets created and can be reset if the temporary namespace has
been created in a transaction or sub-transaction which is aborted.  The
flag value assignment is assumed to be atomic, so this can be done in a
lock-less fashion like other flags already present in PGPROC like
databaseId or backendId, still the fact that the temporary namespace and
table created are still locked until the transaction creating those
commits acts as a barrier for other backends.

This new flag gets used by autovacuum to discard more aggressively
orphaned tables by additionally checking for the database a backend is
connected to as well as its temporary namespace in-use, removing
orphaned temporary relations even if a backend reuses the same slot as
one which created temporary relations in a past session.

The base idea of this patch comes from Robert Haas, has been written in
its first version by Tsunakawa Takayuki, then heavily reviewed by me.

Author: Tsunakawa Takayuki
Reviewed-by: Michael Paquier, Kyotaro Horiguchi, Andres Freund
Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8A4DC6@G01JPEXMBYT05
Backpatch: 11-, as PGPROC gains a new flag and we don't want silent ABI
breakages on already released versions.
2018-08-13 11:49:04 +02:00
config Revert "Distinguish printf-like functions that support %m from those that don't." 2018-08-12 18:46:01 -04:00
contrib Spell "partitionwise" consistently. 2018-08-09 10:43:18 +03:00
doc Add missing documentation for argument of amcostestimate() 2018-08-10 14:14:36 +03:00
src Make autovacuum more aggressive to remove orphaned temp tables 2018-08-13 11:49:04 +02:00
.dir-locals.el Update documentation editor setup instructions 2018-07-13 21:23:41 +02:00
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
COPYRIGHT Update copyright for 2018 2018-01-02 23:30:12 -05:00
GNUmakefile.in Remove unwanted "garbage cleanup" logic in Makefiles. 2018-08-08 14:32:29 -04:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Fix non-GNU makefiles for AIX make. 2017-11-30 00:57:22 -08:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
aclocal.m4 Add configure infrastructure (--with-llvm) to enable LLVM support. 2018-03-20 17:26:25 -07:00
configure Revert "Distinguish printf-like functions that support %m from those that don't." 2018-08-12 18:46:01 -04:00
configure.in Use setproctitle_fast() to update the ps status, if available. 2018-07-24 13:09:22 +12:00

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/.