mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2025-02-05 19:09:58 +08:00
Code Issues Packages Projects Releases Wiki Activity

In documentaiton, clarify which commands have reduced WAL volume for

Browse Source 
wal_level = minimum.

Backpatch to 9.1 and 9.0.
This commit is contained in:
Bruce Momjian 2011-08-04 12:06:54 -04:00
parent d3061f036d
commit 072e6076d1
1 changed files with 12 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
doc/src/sgml/config.sgml
View File

@ -1416,11 +1416,18 @@ 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