diff options
| author | Bruce Momjian <bruce@momjian.us> | 2010-08-24 13:32:32 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2010-08-24 13:32:32 +0000 |
| commit | fad4b0013de408852af6d0dcb906742d0b41553e (patch) | |
| tree | d207bedd861095694ec2045f2174c1616da0311e | |
| parent | 914a2f6e987632bc6c5567e87d006459c38a423c (diff) | |
Update autovacuum_freeze_max_age documentation to mention that the
default is low because of pg_clog file removal.
Backpatch to 9.0.X.
| -rw-r--r-- | doc/src/sgml/config.sgml | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 0d1361a7f85..e4783013ca9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.294.2.7 2010/08/23 02:43:35 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.294.2.8 2010/08/24 13:32:32 momjian Exp $ --> <chapter Id="runtime-config"> <title>Server Configuration</title> @@ -4117,12 +4117,16 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; <para> Specifies the maximum age (in transactions) that a table's <structname>pg_class</>.<structfield>relfrozenxid</> field can - attain before a <command>VACUUM</> operation is forced to allow removal - of old files from the <filename>pg_clog</> subdirectory and prevent - transaction ID wraparound within the table. Note that the system - will launch autovacuum processes to prevent wraparound even when - autovacuum is otherwise disabled. - The default is 200 million transactions. + attain before a <command>VACUUM</> operation is forced + to prevent transaction ID wraparound within the table. + Note that the system will launch autovacuum processes to + prevent wraparound even when autovacuum is otherwise disabled. + </para> + + <para> + Vacuum also allows removal of old files from the + <filename>pg_clog</> subdirectory, which is why the default + is a relatively low 200 million transactions. This parameter can only be set at server start, but the setting can be reduced for individual tables by changing storage parameters. |