Improve UniquePath logic to detect the case where the input is already

known unique (eg, it is a SELECT DISTINCT ... subquery), and not do a
redundant unique-ification step.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/include/optimizer/clauses.h b/src/include/optimizer/clauses.h
index c948a9039fb..947c4467e7b 100644
--- a/src/include/optimizer/clauses.h
+++ b/src/include/optimizer/clauses.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.71 2004/01/04 03:51:52 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.72 2004/01/05 18:04:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -57,6 +57,7 @@ extern bool is_pseudo_constant_clause(Node *clause);
 extern bool is_pseudo_constant_clause_relids(Node *clause, Relids relids);
 extern List *pull_constant_clauses(List *quals, List **constantQual);
 
+extern bool has_distinct_clause(Query *query);
 extern bool has_distinct_on_clause(Query *query);
 
 extern int	NumRelids(Node *clause);