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| -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> |