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.

Author: tglsfdc

src/backend/executor/execAmi.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/executor/execAmi.c,v 1.108 2010/02/14 18:42:14 rhaas Exp $
+ *	$PostgreSQL: pgsql/src/backend/executor/execAmi.c,v 1.109 2010/07/12 17:01:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -59,17 +59,9 @@ static bool IndexSupportsBackwardScan(Oid indexid);
  *
  * Note that if the plan node has parameters that have changed value,
  * the output might be different from last time.
- *
- * The second parameter is currently only used to pass a NestLoop plan's
- * econtext down to its inner child plan, in case that is an indexscan that
- * needs access to variables of the current outer tuple.  (The handling of
- * this parameter is currently pretty inconsistent: some callers pass NULL
- * and some pass down their parent's value; so don't rely on it in other
- * situations.	It'd probably be better to remove the whole thing and use
- * the generalized parameter mechanism instead.)
  */
 void
-ExecReScan(PlanState *node, ExprContext *exprCtxt)
+ExecReScan(PlanState *node)
 {
 	/* If collecting timing stats, update them */
 	if (node->instrument)
@@ -126,119 +118,119 @@ ExecReScan(PlanState *node, ExprContext *exprCtxt)
 	switch (nodeTag(node))
 	{
 		case T_ResultState:
-			ExecReScanResult((ResultState *) node, exprCtxt);
+			ExecReScanResult((ResultState *) node);
 			break;
 
 		case T_ModifyTableState:
-			ExecReScanModifyTable((ModifyTableState *) node, exprCtxt);
+			ExecReScanModifyTable((ModifyTableState *) node);
 			break;
 
 		case T_AppendState:
-			ExecReScanAppend((AppendState *) node, exprCtxt);
+			ExecReScanAppend((AppendState *) node);
 			break;
 
 		case T_RecursiveUnionState:
-			ExecRecursiveUnionReScan((RecursiveUnionState *) node, exprCtxt);
+			ExecReScanRecursiveUnion((RecursiveUnionState *) node);
 			break;
 
 		case T_BitmapAndState:
-			ExecReScanBitmapAnd((BitmapAndState *) node, exprCtxt);
+			ExecReScanBitmapAnd((BitmapAndState *) node);
 			break;
 
 		case T_BitmapOrState:
-			ExecReScanBitmapOr((BitmapOrState *) node, exprCtxt);
+			ExecReScanBitmapOr((BitmapOrState *) node);
 			break;
 
 		case T_SeqScanState:
-			ExecSeqReScan((SeqScanState *) node, exprCtxt);
+			ExecReScanSeqScan((SeqScanState *) node);
 			break;
 
 		case T_IndexScanState:
-			ExecIndexReScan((IndexScanState *) node, exprCtxt);
+			ExecReScanIndexScan((IndexScanState *) node);
 			break;
 
 		case T_BitmapIndexScanState:
-			ExecBitmapIndexReScan((BitmapIndexScanState *) node, exprCtxt);
+			ExecReScanBitmapIndexScan((BitmapIndexScanState *) node);
 			break;
 
 		case T_BitmapHeapScanState:
-			ExecBitmapHeapReScan((BitmapHeapScanState *) node, exprCtxt);
+			ExecReScanBitmapHeapScan((BitmapHeapScanState *) node);
 			break;
 
 		case T_TidScanState:
-			ExecTidReScan((TidScanState *) node, exprCtxt);
+			ExecReScanTidScan((TidScanState *) node);
 			break;
 
 		case T_SubqueryScanState:
-			ExecSubqueryReScan((SubqueryScanState *) node, exprCtxt);
+			ExecReScanSubqueryScan((SubqueryScanState *) node);
 			break;
 
 		case T_FunctionScanState:
-			ExecFunctionReScan((FunctionScanState *) node, exprCtxt);
+			ExecReScanFunctionScan((FunctionScanState *) node);
 			break;
 
 		case T_ValuesScanState:
-			ExecValuesReScan((ValuesScanState *) node, exprCtxt);
+			ExecReScanValuesScan((ValuesScanState *) node);
 			break;
 
 		case T_CteScanState:
-			ExecCteScanReScan((CteScanState *) node, exprCtxt);
+			ExecReScanCteScan((CteScanState *) node);
 			break;
 
 		case T_WorkTableScanState:
-			ExecWorkTableScanReScan((WorkTableScanState *) node, exprCtxt);
+			ExecReScanWorkTableScan((WorkTableScanState *) node);
 			break;
 
 		case T_NestLoopState:
-			ExecReScanNestLoop((NestLoopState *) node, exprCtxt);
+			ExecReScanNestLoop((NestLoopState *) node);
 			break;
 
 		case T_MergeJoinState:
-			ExecReScanMergeJoin((MergeJoinState *) node, exprCtxt);
+			ExecReScanMergeJoin((MergeJoinState *) node);
 			break;
 
 		case T_HashJoinState:
-			ExecReScanHashJoin((HashJoinState *) node, exprCtxt);
+			ExecReScanHashJoin((HashJoinState *) node);
 			break;
 
 		case T_MaterialState:
-			ExecMaterialReScan((MaterialState *) node, exprCtxt);
+			ExecReScanMaterial((MaterialState *) node);
 			break;
 
 		case T_SortState:
-			ExecReScanSort((SortState *) node, exprCtxt);
+			ExecReScanSort((SortState *) node);
 			break;
 
 		case T_GroupState:
-			ExecReScanGroup((GroupState *) node, exprCtxt);
+			ExecReScanGroup((GroupState *) node);
 			break;
 
 		case T_AggState:
-			ExecReScanAgg((AggState *) node, exprCtxt);
+			ExecReScanAgg((AggState *) node);
 			break;
 
 		case T_WindowAggState:
-			ExecReScanWindowAgg((WindowAggState *) node, exprCtxt);
+			ExecReScanWindowAgg((WindowAggState *) node);
 			break;
 
 		case T_UniqueState:
-			ExecReScanUnique((UniqueState *) node, exprCtxt);
+			ExecReScanUnique((UniqueState *) node);
 			break;
 
 		case T_HashState:
-			ExecReScanHash((HashState *) node, exprCtxt);
+			ExecReScanHash((HashState *) node);
 			break;
 
 		case T_SetOpState:
-			ExecReScanSetOp((SetOpState *) node, exprCtxt);
+			ExecReScanSetOp((SetOpState *) node);
 			break;
 
 		case T_LockRowsState:
-			ExecReScanLockRows((LockRowsState *) node, exprCtxt);
+			ExecReScanLockRows((LockRowsState *) node);
 			break;
 
 		case T_LimitState:
-			ExecReScanLimit((LimitState *) node, exprCtxt);
+			ExecReScanLimit((LimitState *) node);
 			break;
 
 		default:

src/backend/executor/execMain.c

@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.350 2010/07/09 14:06:01 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.351 2010/07/12 17:01:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -400,7 +400,7 @@ ExecutorRewind(QueryDesc *queryDesc)
 	/*
 	 * rescan plan
 	 */
-	ExecReScan(queryDesc->planstate, NULL);
+	ExecReScan(queryDesc->planstate);
 
 	MemoryContextSwitchTo(oldcontext);
 }

src/backend/executor/execProcnode.c

@@ -12,7 +12,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execProcnode.c,v 1.70 2010/01/02 16:57:41 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execProcnode.c,v 1.71 2010/07/12 17:01:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -341,7 +341,7 @@ ExecProcNode(PlanState *node)
 	CHECK_FOR_INTERRUPTS();
 
 	if (node->chgParam != NULL) /* something changed */
-		ExecReScan(node, NULL); /* let ReScan handle this */
+		ExecReScan(node);		/* let ReScan handle this */
 
 	if (node->instrument)
 		InstrStartNode(node->instrument);
@@ -504,7 +504,7 @@ MultiExecProcNode(PlanState *node)
 	CHECK_FOR_INTERRUPTS();
 
 	if (node->chgParam != NULL) /* something changed */
-		ExecReScan(node, NULL); /* let ReScan handle this */
+		ExecReScan(node);		/* let ReScan handle this */
 
 	switch (nodeTag(node))
 	{