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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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11
src/backend/optimizer/path/equivclass.c
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@@ -10,7 +10,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/equivclass.c,v 1.16 2009/01/01 17:23:43 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/equivclass.c,v 1.17 2009/02/06 23:43:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1200,7 +1200,8 @@ reconsider_outer_join_clauses(PlannerInfo *root)
list_delete_cell(root->left_join_clauses, cell, prev);
/* we throw it back anyway (see notes above) */
/* but the thrown-back clause has no extra selectivity */
rinfo->this_selec = 2.0;
rinfo->norm_selec = 2.0;
rinfo->outer_selec = 1.0;
distribute_restrictinfo_to_rels(root, rinfo);
}
else
@@ -1222,7 +1223,8 @@ reconsider_outer_join_clauses(PlannerInfo *root)
list_delete_cell(root->right_join_clauses, cell, prev);
/* we throw it back anyway (see notes above) */
/* but the thrown-back clause has no extra selectivity */
rinfo->this_selec = 2.0;
rinfo->norm_selec = 2.0;
rinfo->outer_selec = 1.0;
distribute_restrictinfo_to_rels(root, rinfo);
}
else
@@ -1244,7 +1246,8 @@ reconsider_outer_join_clauses(PlannerInfo *root)
list_delete_cell(root->full_join_clauses, cell, prev);
/* we throw it back anyway (see notes above) */
/* but the thrown-back clause has no extra selectivity */
rinfo->this_selec = 2.0;
rinfo->norm_selec = 2.0;
rinfo->outer_selec = 1.0;
distribute_restrictinfo_to_rels(root, rinfo);
}
else