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| author | Bruce Momjian <bruce@momjian.us> | 2011-08-04 12:06:53 -0400 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2011-08-04 12:06:53 -0400 |
| commit | 857433b80e99e53b2187fd6a58dacaf2181fb8ce (patch) | |
| tree | 0ad3212c3e2e9de957021229094c5e032dbe4fc7 | |
| parent | 1318f1ad775d310fc7ce045603432c0f810dcdbf (diff) | |
In documentaiton, clarify which commands have reduced WAL volume for
wal_level = minimum.
Backpatch to 9.1 and 9.0.
| -rw-r--r-- | doc/src/sgml/config.sgml | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index f77ae48bb5b..d8de339a656 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1420,11 +1420,18 @@ SET ENABLE_SEQSCAN TO OFF; This parameter can only be set at server start. </para> <para> - In <literal>minimal</> level, WAL-logging of some bulk operations, like - <command>CREATE INDEX</>, <command>CLUSTER</> and <command>COPY</> on - a table that was created or truncated in the same transaction can be - safely skipped, which can make those operations much faster (see - <xref linkend="populate-pitr">). But minimal WAL does not contain + In <literal>minimal</> level, WAL-logging of some bulk + operations can be safely skipped, which can make those + operations much faster (see <xref linkend="populate-pitr">). + Operations in which this optimization can be applied include: + <simplelist> + <item>CREATE TABLE AS</item> + <item>CREATE INDEX</item> + <item>CLUSTER</item> + <item>COPY into tables that were created or truncated in the same + transaction + </simplelist> + But minimal WAL does not contain enough information to reconstruct the data from a base backup and the WAL logs, so either <literal>archive</> or <literal>hot_standby</> level must be used to enable |