Create a 'type cache' that keeps track of the data needed for any particular

datatype by array_eq and array_cmp; use this to solve problems with memory
leaks in array indexing support.  The parser's equality_oper and ordering_oper
routines also use the cache.  Change the operator search algorithms to look
for appropriate btree or hash index opclasses, instead of assuming operators
named '<' or '=' have the right semantics.  (ORDER BY ASC/DESC now also look
at opclasses, instead of assuming '<' and '>' are the right things.)  Add
several more index opclasses so that there is no regression in functionality
for base datatypes.  initdb forced due to catalog additions.

src/include/nodes/parsenodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parsenodes.h,v 1.246 2003/08/08 21:42:48 momjian Exp $
+ * $Id: parsenodes.h,v 1.247 2003/08/17 19:58:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -279,14 +279,19 @@ typedef struct ResTarget
 } ResTarget;
 
 /*
- * SortGroupBy - for ORDER BY clause
+ * SortBy - for ORDER BY clause
  */
-typedef struct SortGroupBy
+#define SORTBY_ASC		1
+#define SORTBY_DESC		2
+#define SORTBY_USING	3
+
+typedef struct SortBy
 {
 	NodeTag		type;
-	List	   *useOp;			/* operator to use */
-	Node	   *node;			/* Expression  */
-} SortGroupBy;
+	int			sortby_kind;	/* see codes above */
+	List	   *useOp;			/* name of op to use, if SORTBY_USING */
+	Node	   *node;			/* expression to sort on */
+} SortBy;
 
 /*
  * RangeSubselect - subquery appearing in a FROM clause
@@ -614,7 +619,7 @@ typedef struct SelectStmt
 	 * These fields are used in both "leaf" SelectStmts and upper-level
 	 * SelectStmts.
 	 */
-	List	   *sortClause;		/* sort clause (a list of SortGroupBy's) */
+	List	   *sortClause;		/* sort clause (a list of SortBy's) */
 	Node	   *limitOffset;	/* # of result tuples to skip */
 	Node	   *limitCount;		/* # of result tuples to return */
 	List	   *forUpdate;		/* FOR UPDATE clause */