Turn the rangetable used by the executor into a flat list, and avoid storing

useless substructure for its RangeTblEntry nodes.  (I chose to keep using the
same struct node type and just zero out the link fields for unneeded info,
rather than making a separate ExecRangeTblEntry type --- it seemed too
fragile to have two different rangetable representations.)

Along the way, put subplans into a list in the toplevel PlannedStmt node,
and have SubPlan nodes refer to them by list index instead of direct pointers.
Vadim wanted to do that years ago, but I never understood what he was on about
until now.  It makes things a *whole* lot more robust, because we can stop
worrying about duplicate processing of subplans during expression tree
traversals.  That's been a constant source of bugs, and it's finally gone.

There are some consequent simplifications yet to be made, like not using
a separate EState for subplans in the executor, but I'll tackle that later.

1 files changed, 8 insertions, 9 deletions

diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 32167a94efb..9bc96921f41 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.85 2007/02/06 02:59:11 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.86 2007/02/22 22:00:23 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -637,14 +637,10 @@ void
 ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
 {
 	SubPlan    *subplan = (SubPlan *) node->xprstate.expr;
+	Plan	   *plan = exec_subplan_get_plan(estate->es_plannedstmt, subplan);
 	EState	   *sp_estate;
 
 	/*
-	 * Do access checking on the rangetable entries in the subquery.
-	 */
-	ExecCheckRTPerms(subplan->rtable);
-
-	/*
 	 * initialize my state
 	 */
 	node->needShutdown = false;
@@ -668,18 +664,21 @@ ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
 	 * shares our Param ID space and es_query_cxt, however.  XXX if rangetable
 	 * access were done differently, the subquery could share our EState,
 	 * which would eliminate some thrashing about in this module...
+	 *
+	 * XXX make that happen!
 	 */
 	sp_estate = CreateSubExecutorState(estate);
 	node->sub_estate = sp_estate;
 
-	sp_estate->es_range_table = subplan->rtable;
+	sp_estate->es_range_table = estate->es_range_table;
 	sp_estate->es_param_list_info = estate->es_param_list_info;
 	sp_estate->es_param_exec_vals = estate->es_param_exec_vals;
 	sp_estate->es_tupleTable =
-		ExecCreateTupleTable(ExecCountSlotsNode(subplan->plan) + 10);
+		ExecCreateTupleTable(ExecCountSlotsNode(plan) + 10);
 	sp_estate->es_snapshot = estate->es_snapshot;
 	sp_estate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
 	sp_estate->es_instrument = estate->es_instrument;
+	sp_estate->es_plannedstmt = estate->es_plannedstmt;
 
 	/*
 	 * Start up the subplan (this is a very cut-down form of InitPlan())
@@ -692,7 +691,7 @@ ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
 	if (subplan->parParam == NIL && subplan->setParam == NIL)
 		eflags |= EXEC_FLAG_REWIND;
 
-	node->planstate = ExecInitNode(subplan->plan, sp_estate, eflags);
+	node->planstate = ExecInitNode(plan, sp_estate, eflags);
 
 	node->needShutdown = true;	/* now we need to shutdown the subplan */