From 445ce15702f701423a0fed3defe3a43662c7cd8d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 7 Jan 2009 22:40:49 +0000 Subject: Create a third option named "partition" for constraint_exclusion, and make it the default. This setting enables constraint exclusion checks only for appendrel members (ie, inheritance children and UNION ALL arms), which are the cases in which constraint exclusion is most likely to be useful. Avoiding the overhead for simple queries that are unlikely to benefit should bring the cost down to the point where this is a reasonable default setting. Per today's discussion. --- src/backend/utils/misc/postgresql.conf.sample | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/backend/utils/misc/postgresql.conf.sample') diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index e28feb8e428..d53861511ae 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -211,7 +211,7 @@ # - Other Planner Options - #default_statistics_target = 100 # range 1-10000 -#constraint_exclusion = off +#constraint_exclusion = partition # on, off, or partition #cursor_tuple_fraction = 0.1 # range 0.0-1.0 #from_collapse_limit = 8 #join_collapse_limit = 8 # 1 disables collapsing of explicit -- cgit v1.2.3