From 6cda3ad8feb9b534fe9fb5866bbe5930596d0027 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 9 May 2001 00:35:09 +0000 Subject: Cause planner to make use of average-column-width statistic that is now collected by ANALYZE. Also, add some modest amount of intelligence to guesses that are used for varlena columns in the absence of any ANALYZE statistics. The 'width' reported by EXPLAIN is finally something less than totally bogus for varlena columns ... and, in consequence, hashjoin estimating should be a little better ... --- doc/src/sgml/perform.sgml | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'doc/src') diff --git a/doc/src/sgml/perform.sgml b/doc/src/sgml/perform.sgml index 77e1c77d8f6..bfe66eb5dc5 100644 --- a/doc/src/sgml/perform.sgml +++ b/doc/src/sgml/perform.sgml @@ -1,5 +1,5 @@ @@ -97,13 +97,6 @@ $Header: /cvsroot/pgsql/doc/src/sgml/perform.sgml,v 1.3 2001/03/24 23:03:26 pete by the query (again, without considering the effects of LIMIT). - - Average width is pretty bogus because the thing really doesn't have - any idea of the average length of variable-length columns. I'm thinking - about improving that in the future, but it may not be worth the trouble, - because the width isn't used for very much. - - Here are some examples (using the regress test database after a vacuum analyze, and almost-7.0 sources): -- cgit v1.2.3