diff options
| -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 06ff79a4172..d1ad1af6af8 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 1.307 2010/08/23 02:43:25 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.308 2010/08/24 13:32:25 momjian Exp $ --> <chapter Id="runtime-config"> <title>Server Configuration</title> @@ -4150,12 +4150,16 @@ 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. |