From 05e3d0ee8666b74f11ffad16f46e372459d6e53e Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 5 Oct 2000 19:11:39 +0000
Subject: Reimplementation of UNION/INTERSECT/EXCEPT.  INTERSECT/EXCEPT now
 meet the SQL92 semantics, including support for ALL option.  All three can be
 used in subqueries and views.  DISTINCT and ORDER BY work now in views, too.
 This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
 where the SELECT yields different datatypes than the INSERT needs.  I did
 that by making UNION subqueries and SELECT in INSERT be treated like
 subselects-in-FROM, thereby allowing an extra level of targetlist where the
 datatype conversions can be inserted safely. INITDB NEEDED!

---
 src/backend/executor/nodeSubqueryscan.c | 55 ++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 29 deletions(-)

(limited to 'src/backend/executor/nodeSubqueryscan.c')

diff --git a/src/backend/executor/nodeSubqueryscan.c b/src/backend/executor/nodeSubqueryscan.c
index 45f07a08b10..5593f71d0c6 100644
--- a/src/backend/executor/nodeSubqueryscan.c
+++ b/src/backend/executor/nodeSubqueryscan.c
@@ -3,12 +3,16 @@
  * nodeSubqueryscan.c
  *	  Support routines for scanning subqueries (subselects in rangetable).
  *
+ * This is just enough different from sublinks (nodeSubplan.c) to mean that
+ * we need two sets of code.  Ought to look at trying to unify the cases.
+ *
+ *
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeSubqueryscan.c,v 1.1 2000/09/29 18:21:29 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeSubqueryscan.c,v 1.2 2000/10/05 19:11:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -49,9 +53,7 @@ SubqueryNext(SubqueryScan *node)
 	SubqueryScanState *subquerystate;
 	EState	   *estate;
 	ScanDirection direction;
-	int			execdir;
 	TupleTableSlot *slot;
-	Const		countOne;
 
 	/* ----------------
 	 *	get information from the estate and scan state
@@ -60,7 +62,6 @@ SubqueryNext(SubqueryScan *node)
 	estate = node->scan.plan.state;
 	subquerystate = (SubqueryScanState *) node->scan.scanstate;
 	direction = estate->es_direction;
-	execdir = ScanDirectionIsBackward(direction) ? EXEC_BACK : EXEC_FOR;
 	slot = subquerystate->csstate.css_ScanTupleSlot;
 
 	/*
@@ -85,25 +86,13 @@ SubqueryNext(SubqueryScan *node)
 		return (slot);
 	}
 
-	memset(&countOne, 0, sizeof(countOne));
-	countOne.type = T_Const;
-	countOne.consttype = INT4OID;
-	countOne.constlen = sizeof(int4);
-	countOne.constvalue = Int32GetDatum(1);
-	countOne.constisnull = false;
-	countOne.constbyval = true;
-	countOne.constisset = false;
-	countOne.constiscast = false;
-
 	/* ----------------
 	 *	get the next tuple from the sub-query
 	 * ----------------
 	 */
-	slot = ExecutorRun(subquerystate->sss_SubQueryDesc,
-					   subquerystate->sss_SubEState,
-					   execdir,
-					   NULL,	/* offset */
-					   (Node *) &countOne);
+	subquerystate->sss_SubEState->es_direction = direction;
+
+	slot = ExecProcNode(node->subplan, node->subplan);
 
 	subquerystate->csstate.css_ScanTupleSlot = slot;
 
@@ -139,6 +128,7 @@ ExecInitSubqueryScan(SubqueryScan *node, EState *estate, Plan *parent)
 {
 	SubqueryScanState *subquerystate;
 	RangeTblEntry *rte;
+	EState	   *sp_estate;
 
 	/* ----------------
 	 *	SubqueryScan should not have any "normal" children.
@@ -177,18 +167,25 @@ ExecInitSubqueryScan(SubqueryScan *node, EState *estate, Plan *parent)
 
 	/* ----------------
 	 *	initialize subquery
+	 *
+	 *	This should agree with ExecInitSubPlan
 	 * ----------------
 	 */
 	rte = rt_fetch(node->scan.scanrelid, estate->es_range_table);
 	Assert(rte->subquery != NULL);
 
-	subquerystate->sss_SubQueryDesc = CreateQueryDesc(rte->subquery,
-													  node->subplan,
-													  None);
-	subquerystate->sss_SubEState = CreateExecutorState();
+	sp_estate = CreateExecutorState();
+	subquerystate->sss_SubEState = sp_estate;
+
+	sp_estate->es_range_table = rte->subquery->rtable;
+	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(node->subplan) + 10);
+	sp_estate->es_snapshot = estate->es_snapshot;
 
-	ExecutorStart(subquerystate->sss_SubQueryDesc,
-				  subquerystate->sss_SubEState);
+	if (!ExecInitNode(node->subplan, sp_estate, NULL))
+		return false;
 
 	subquerystate->csstate.css_ScanTupleSlot = NULL;
 	subquerystate->csstate.cstate.cs_TupFromTlist = false;
@@ -247,10 +244,9 @@ ExecEndSubqueryScan(SubqueryScan *node)
 	 * close down subquery
 	 * ----------------
 	 */
-	ExecutorEnd(subquerystate->sss_SubQueryDesc,
-				subquerystate->sss_SubEState);
+	ExecEndNode(node->subplan, node->subplan);
 
-	/* XXX we seem to be leaking the querydesc and sub-EState... */
+	/* XXX we seem to be leaking the sub-EState and tuple table... */
 
 	subquerystate->csstate.css_ScanTupleSlot = NULL;
 
@@ -284,6 +280,7 @@ ExecSubqueryReScan(SubqueryScan *node, ExprContext *exprCtxt, Plan *parent)
 		return;
 	}
 
-	ExecReScan(node->subplan, NULL, NULL);
+	ExecReScan(node->subplan, NULL, node->subplan);
+
 	subquerystate->csstate.css_ScanTupleSlot = NULL;
 }
-- 
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