Make NestLoop plan nodes pass outer-relation variables into their inner

relation using the general PARAM_EXEC executor parameter mechanism, rather
than the ad-hoc kluge of passing the outer tuple down through ExecReScan.
The previous method was hard to understand and could never be extended to
handle parameters coming from multiple join levels.  This patch doesn't
change the set of possible plans nor have any significant performance effect,
but it's necessary infrastructure for future generalization of the concept
of an inner indexscan plan.

ExecReScan's second parameter is now unused, so it's removed.

1 files changed, 8 insertions, 19 deletions

diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index 2a7ce624321..0ea3a88e451 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -21,7 +21,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.38 2010/01/02 16:57:41 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.39 2010/07/12 17:01:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,7 +30,7 @@
  *		ExecBitmapHeapScan			scans a relation using bitmap info
  *		ExecBitmapHeapNext			workhorse for above
  *		ExecInitBitmapHeapScan		creates and initializes state info.
- *		ExecBitmapHeapReScan		prepares to rescan the plan.
+ *		ExecReScanBitmapHeapScan	prepares to rescan the plan.
  *		ExecEndBitmapHeapScan		releases all storage.
  */
 #include "postgres.h"
@@ -420,24 +420,12 @@ ExecBitmapHeapScan(BitmapHeapScanState *node)
 }
 
 /* ----------------------------------------------------------------
- *		ExecBitmapHeapReScan(node)
+ *		ExecReScanBitmapHeapScan(node)
  * ----------------------------------------------------------------
  */
 void
-ExecBitmapHeapReScan(BitmapHeapScanState *node, ExprContext *exprCtxt)
+ExecReScanBitmapHeapScan(BitmapHeapScanState *node)
 {
-	/*
-	 * If we are being passed an outer tuple, link it into the "regular"
-	 * per-tuple econtext for possible qual eval.
-	 */
-	if (exprCtxt != NULL)
-	{
-		ExprContext *stdecontext;
-
-		stdecontext = node->ss.ps.ps_ExprContext;
-		stdecontext->ecxt_outertuple = exprCtxt->ecxt_outertuple;
-	}
-
 	/* rescan to release any page pin */
 	heap_rescan(node->ss.ss_currentScanDesc, NULL);
 
@@ -455,10 +443,11 @@ ExecBitmapHeapReScan(BitmapHeapScanState *node, ExprContext *exprCtxt)
 	ExecScanReScan(&node->ss);
 
 	/*
-	 * Always rescan the input immediately, to ensure we can pass down any
-	 * outer tuple that might be used in index quals.
+	 * if chgParam of subnode is not null then plan will be re-scanned by
+	 * first ExecProcNode.
 	 */
-	ExecReScan(outerPlanState(node), exprCtxt);
+	if (node->ss.ps.lefttree->chgParam == NULL)
+		ExecReScan(node->ss.ps.lefttree);
 }
 
 /* ----------------------------------------------------------------