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Fix cost_mergejoin's failure to adjust for rescanning of non-unique merge join

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keys when considering a semi or anti join.  This requires estimating the
selectivity of the merge qual as though it were a regular inner join condition.
To allow caching both that and the real outer-join-aware selectivity, split
RestrictInfo.this_selec into two fields.

This fixes one of the problems reported by Kevin Grittner.
This commit is contained in:
Tom Lane
2009-02-06 23:43:24 +00:00
parent c87c31f10b
commit c473d92351
9 changed files with 86 additions and 53 deletions
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5
src/backend/optimizer/prep/prepunion.c
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@@ -22,7 +22,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.164 2009/01/01 17:23:44 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.165 2009/02/06 23:43:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1662,7 +1662,8 @@ adjust_appendrel_attrs_mutator(Node *node, AppendRelInfo *context)
* different values when considering the child relation.
*/
newinfo->eval_cost.startup = -1;
newinfo->this_selec = -1;
newinfo->norm_selec = -1;
newinfo->outer_selec = -1;
newinfo->left_ec = NULL;
newinfo->right_ec = NULL;
newinfo->left_em = NULL;