From 38de5aad54b3eb37981cacd391fcde82f86d00fb Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Thu, 4 Aug 2011 12:06:53 -0400 Subject: [PATCH] In documentaiton, clarify which commands have reduced WAL volume for wal_level = minimum. Backpatch to 9.1 and 9.0. --- doc/src/sgml/config.sgml | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 4fadca955c..b774e2a332 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1451,11 +1451,18 @@ SET ENABLE_SEQSCAN TO OFF; This parameter can only be set at server start. - In minimal level, WAL-logging of some bulk operations, like - CREATE INDEX, CLUSTER and 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 - ). But minimal WAL does not contain + In minimal level, WAL-logging of some bulk + operations can be safely skipped, which can make those + operations much faster (see ). + Operations in which this optimization can be applied include: + + CREATE TABLE AS + CREATE INDEX + CLUSTER + COPY into tables that were created or truncated in the same + transaction + + But minimal WAL does not contain enough information to reconstruct the data from a base backup and the WAL logs, so either archive or hot_standby level must be used to enable