Change expandRTE() and ResolveNew() back to taking just the single

RTE of interest, rather than the whole rangetable list.  This makes
the API more understandable and avoids duplicate RTE lookups.  This
patch reverts no-longer-needed portions of my patch of 2004-08-19.

1 files changed, 23 insertions, 9 deletions

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 3c267ccdcd2..b7a96922e94 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.153 2005/06/03 23:05:28 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.154 2005/06/04 19:19:42 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -106,6 +106,8 @@ AcquireRewriteLocks(Query *parsetree)
 		Relation	rel;
 		LOCKMODE	lockmode;
 		List	   *newaliasvars;
+		Index		curinputvarno;
+		RangeTblEntry *curinputrte;
 		ListCell   *ll;
 
 		++rt_index;
@@ -140,8 +142,14 @@ AcquireRewriteLocks(Query *parsetree)
 				 * Scan the join's alias var list to see if any columns
 				 * have been dropped, and if so replace those Vars with
 				 * NULL Consts.
+				 *
+				 * Since a join has only two inputs, we can expect to
+				 * see multiple references to the same input RTE; optimize
+				 * away multiple fetches.
 				 */
 				newaliasvars = NIL;
+				curinputvarno = 0;
+				curinputrte = NULL;
 				foreach(ll, rte->joinaliasvars)
 				{
 					Var		   *aliasvar = (Var *) lfirst(ll);
@@ -165,12 +173,17 @@ AcquireRewriteLocks(Query *parsetree)
 						 * but it's OK to assume here.)
 						 */
 						Assert(aliasvar->varlevelsup == 0);
-						if (aliasvar->varno >= rt_index)
-							elog(ERROR, "unexpected varno %d in JOIN RTE %d",
-								 aliasvar->varno, rt_index);
-						if (get_rte_attribute_is_dropped(
-							rt_fetch(aliasvar->varno, parsetree->rtable),
-							aliasvar->varattno))
+						if (aliasvar->varno != curinputvarno)
+						{
+							curinputvarno = aliasvar->varno;
+							if (curinputvarno >= rt_index)
+								elog(ERROR, "unexpected varno %d in JOIN RTE %d",
+									 curinputvarno, rt_index);
+							curinputrte = rt_fetch(curinputvarno,
+												   parsetree->rtable);
+						}
+						if (get_rte_attribute_is_dropped(curinputrte,
+														 aliasvar->varattno))
 						{
 							/*
 							 * can't use vartype here, since that might be a
@@ -386,7 +399,8 @@ rewriteRuleAction(Query *parsetree,
 		sub_action = (Query *) ResolveNew((Node *) sub_action,
 										  new_varno,
 										  0,
-										  sub_action->rtable,
+										  rt_fetch(new_varno,
+												   sub_action->rtable),
 										  parsetree->targetList,
 										  event,
 										  current_varno);
@@ -1206,7 +1220,7 @@ CopyAndAddInvertedQual(Query *parsetree,
 		new_qual = ResolveNew(new_qual,
 							  PRS2_NEW_VARNO,
 							  0,
-							  parsetree->rtable,
+							  rt_fetch(rt_index, parsetree->rtable),
 							  parsetree->targetList,
 							  event,
 							  rt_index);