Rewrite OR indexscan processing to be more flexible. We can now for the

first time generate an OR indexscan for a two-column index when the WHERE
condition is like 'col1 = foo AND (col2 = bar OR col2 = baz)' --- before,
the OR had to be on the first column of the index or we'd not notice the
possibility of using it.  Some progress towards extracting OR indexscans
from subclauses of an OR that references multiple relations, too, although
this code is #ifdef'd out because it needs more work.

Author: tglsfdc

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.270 2003/12/30 23:53:14 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.271 2004/01/04 00:07:32 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1172,7 +1172,7 @@ _copyRestrictInfo(RestrictInfo *from)
 	COPY_SCALAR_FIELD(canjoin);
 	COPY_BITMAPSET_FIELD(left_relids);
 	COPY_BITMAPSET_FIELD(right_relids);
-	COPY_NODE_FIELD(subclauseindices);	/* XXX probably bad */
+	COPY_NODE_FIELD(orclause);
 	COPY_SCALAR_FIELD(eval_cost);
 	COPY_SCALAR_FIELD(this_selec);
 	COPY_SCALAR_FIELD(mergejoinoperator);

src/backend/nodes/outfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.223 2003/12/30 23:53:14 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.224 2004/01/04 00:07:32 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -1077,7 +1077,7 @@ _outRestrictInfo(StringInfo str, RestrictInfo *node)
 	WRITE_BOOL_FIELD(canjoin);
 	WRITE_BITMAPSET_FIELD(left_relids);
 	WRITE_BITMAPSET_FIELD(right_relids);
-	WRITE_NODE_FIELD(subclauseindices);
+	WRITE_NODE_FIELD(orclause);
 	WRITE_OID_FIELD(mergejoinoperator);
 	WRITE_OID_FIELD(left_sortop);
 	WRITE_OID_FIELD(right_sortop);