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| author | Simon Riggs <simon@2ndQuadrant.com> | 2011-11-03 08:52:20 +0000 |
|---|---|---|
| committer | Simon Riggs <simon@2ndQuadrant.com> | 2011-11-03 08:52:20 +0000 |
| commit | 43342891861cc2d08dea2b1c8b190e15e5a36551 (patch) | |
| tree | 9e93a0c7f756ffe1dd9e6b759dadde0970dc1505 /doc/src | |
| parent | 7e3bf99baa18524de6ef1492cb3057314da97e68 (diff) | |
| download | postgresql-43342891861cc2d08dea2b1c8b190e15e5a36551.tar.gz postgresql-43342891861cc2d08dea2b1c8b190e15e5a36551.zip | |
Improve docs for timing and skipping of checkpoints
Greg Smith
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/wal.sgml | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index ff825eca3b8..3b86a4e1116 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -424,8 +424,15 @@ linkend="guc-checkpoint-segments"> log segments, or every <xref linkend="guc-checkpoint-timeout"> seconds, whichever comes first. The default settings are 3 segments and 300 seconds (5 minutes), respectively. - It is also possible to force a checkpoint by using the SQL command - <command>CHECKPOINT</command>. + In cases where there are little or no writes to the WAL, checkpoints will be + skipped even if checkpoint_timeout has passed. At least one new WAL segment + must have been created before an automatic checkpoint occurs. The time + between checkpoints and when new WAL segments are created are not related + in any other way. If file-based WAL shipping is being used and you want to + bound how often files are sent to standby server, to reduce potential data + loss you should adjust archive_timeout parameter rather than the checkpoint + parameters. It is also possible to force a checkpoint by using the SQL + command <command>CHECKPOINT</command>. </para> <para> |