Teach planner and executor to handle ScalarArrayOpExpr as an indexable

qualification when the underlying operator is indexable and useOr is true.
That is, indexkey op ANY (ARRAY[...]) is effectively translated into an
OR combination of one indexscan for each array element.  This only works
for bitmap index scans, of course, since regular indexscans no longer
support OR'ing of scans.  There are still some loose ends to clean up
before changing 'x IN (list)' to translate as a ScalarArrayOpExpr;
for instance predtest.c ought to be taught about it.  But this gets the
basic functionality in place.

1 files changed, 36 insertions, 3 deletions

diff --git a/src/backend/optimizer/path/clausesel.c b/src/backend/optimizer/path/clausesel.c
index 9a4990898e9..eba6bf1d148 100644
--- a/src/backend/optimizer/path/clausesel.c
+++ b/src/backend/optimizer/path/clausesel.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.75 2005/10/15 02:49:19 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.76 2005/11/25 19:47:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -624,12 +624,45 @@ clause_selectivity(PlannerInfo *root,
 		 */
 		s1 = (Selectivity) 0.5;
 	}
-	else if (IsA(clause, DistinctExpr) ||
-			 IsA(clause, ScalarArrayOpExpr))
+	else if (IsA(clause, DistinctExpr))
 	{
 		/* can we do better? */
 		s1 = (Selectivity) 0.5;
 	}
+	else if (IsA(clause, ScalarArrayOpExpr))
+	{
+		/* First, decide if it's a join clause, same as for OpExpr */
+		bool		is_join_clause;
+
+		if (varRelid != 0)
+		{
+			/*
+			 * If we are considering a nestloop join then all clauses are
+			 * restriction clauses, since we are only interested in the one
+			 * relation.
+			 */
+			is_join_clause = false;
+		}
+		else
+		{
+			/*
+			 * Otherwise, it's a join if there's more than one relation used.
+			 * We can optimize this calculation if an rinfo was passed.
+			 */
+			if (rinfo)
+				is_join_clause = (bms_membership(rinfo->clause_relids) ==
+								  BMS_MULTIPLE);
+			else
+				is_join_clause = (NumRelids(clause) > 1);
+		}
+
+		/* Use node specific selectivity calculation function */
+		s1 = scalararraysel(root,
+							(ScalarArrayOpExpr *) clause,
+							is_join_clause,
+							varRelid,
+							jointype);
+	}
 	else if (IsA(clause, NullTest))
 	{
 		/* Use node specific selectivity calculation function */