Add COST and ROWS options to CREATE/ALTER FUNCTION, plus underlying pg_proc

columns procost and prorows, to allow simple user adjustment of the estimated
cost of a function call, as well as control of the estimated number of rows
returned by a set-returning function.  We might eventually wish to extend this
to allow function-specific estimation routines, but there seems to be
consensus that we should try a simple constant estimate first.  In particular
this provides a relatively simple way to control the order in which different
WHERE clauses are applied in a plan node, which is a Good Thing in view of the
fact that the recent EquivalenceClass planner rewrite made that much less
predictable than before.

3 files changed, 6 insertions, 3 deletions

diff --git a/src/include/optimizer/clauses.h b/src/include/optimizer/clauses.h
index a115baabae..5001125914 100644
--- a/src/include/optimizer/clauses.h
+++ b/src/include/optimizer/clauses.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.85 2007/01/05 22:19:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.86 2007/01/22 01:35:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -51,6 +51,7 @@ extern bool contain_agg_clause(Node *clause);
 extern void count_agg_clauses(Node *clause, AggClauseCounts *counts);
 
 extern bool expression_returns_set(Node *clause);
+extern double expression_returns_set_rows(Node *clause);
 
 extern bool contain_subplans(Node *clause);
 
diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h
index 9ecfe7ebc8..fde65ed874 100644
--- a/src/include/optimizer/cost.h
+++ b/src/include/optimizer/cost.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.83 2007/01/05 22:19:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.84 2007/01/22 01:35:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -89,6 +89,7 @@ extern void cost_nestloop(NestPath *path, PlannerInfo *root);
 extern void cost_mergejoin(MergePath *path, PlannerInfo *root);
 extern void cost_hashjoin(HashPath *path, PlannerInfo *root);
 extern void cost_qual_eval(QualCost *cost, List *quals);
+extern void cost_qual_eval_node(QualCost *cost, Node *qual);
 extern void set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel);
 extern void set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
 						   RelOptInfo *outer_rel,
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 5118061182..6bf34e162a 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.98 2007/01/20 20:45:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.99 2007/01/22 01:35:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -97,5 +97,6 @@ extern List *set_returning_clause_references(List *rlist,
 								Index resultRelation);
 extern void fix_opfuncids(Node *node);
 extern void set_opfuncid(OpExpr *opexpr);
+extern void set_sa_opfuncid(ScalarArrayOpExpr *opexpr);
 
 #endif   /* PLANMAIN_H */