From 1afaa2557adb86cef224982093201ad035588eeb Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 23 Mar 2000 00:58:36 +0000 Subject: [PATCH] If we cannot get a real estimate for the selectivity of a range query, use a default value that's fairly small. We were generating a result of about 0.1, but I think 0.01 is probably better --- want to encourage use of an indexscan in this situation. --- src/backend/optimizer/path/clausesel.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c index 09d6d277c9..baa99a7d28 100644 --- a/src/backend/optimizer/path/clausesel.c +++ b/src/backend/optimizer/path/clausesel.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/clausesel.c,v 1.31 2000/03/17 02:36:14 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/clausesel.c,v 1.32 2000/03/23 00:58:36 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -194,9 +194,11 @@ clauselist_selectivity(Query *root, else { /* One or both is probably a default estimate, - * so punt and just merge them in generically. + * so supply a default estimate for the selectivity + * of the range query. We rather optimistically assume + * that the range is tight... */ - s1 *= rqlist->hibound * rqlist->lobound; + s1 *= 0.01; } } else -- GitLab