Revert "Do execGrouping.c via expression eval machinery."

This reverts commit 773aec7aa98abd38d6d9435913bb8e14e392c274.

There's an unresolved issue in the reverted commit: It only creates
one comparator function, but in for the nodeSubplan.c case we need
more (c.f. FindTupleHashEntry vs LookupTupleHashEntry calls in
nodeSubplan.c).

This isn't too difficult to fix, but it's not entirely trivial
either. The fact that the issue only causes breakage on 32bit systems
shows that the current test coverage isn't that great.  To avoid
turning half the buildfarm red till those two issues are addressed,
revert.

1 files changed, 13 insertions, 25 deletions

diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index 1c807a82922..f6412576f40 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -1272,13 +1272,12 @@ spool_tuples(WindowAggState *winstate, int64 pos)
 
 		if (node->partNumCols > 0)
 		{
-			ExprContext *econtext = winstate->tmpcontext;
-
-			econtext->ecxt_innertuple = winstate->first_part_slot;
-			econtext->ecxt_outertuple = outerslot;
-
 			/* Check if this tuple still belongs to the current partition */
-			if (!ExecQualAndReset(winstate->partEqfunction, econtext))
+			if (!execTuplesMatch(winstate->first_part_slot,
+								 outerslot,
+								 node->partNumCols, node->partColIdx,
+								 winstate->partEqfunctions,
+								 winstate->tmpcontext->ecxt_per_tuple_memory))
 			{
 				/*
 				 * end of partition; copy the tuple for the next cycle.
@@ -2246,7 +2245,6 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 				wfuncno,
 				numaggs,
 				aggno;
-	TupleDesc	scanDesc;
 	ListCell   *l;
 
 	/* check for unsupported flags */
@@ -2329,7 +2327,6 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 	 * store in the tuplestore and use in all our working slots).
 	 */
 	ExecAssignScanTypeFromOuterPlan(&winstate->ss);
-	scanDesc = winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor;
 
 	ExecSetSlotDescriptor(winstate->first_part_slot,
 						  winstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor);
@@ -2354,20 +2351,11 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 
 	/* Set up data for comparing tuples */
 	if (node->partNumCols > 0)
-		winstate->partEqfunction =
-			execTuplesMatchPrepare(scanDesc,
-								   node->partNumCols,
-								   node->partColIdx,
-								   node->partOperators,
-								   &winstate->ss.ps);
-
+		winstate->partEqfunctions = execTuplesMatchPrepare(node->partNumCols,
+														   node->partOperators);
 	if (node->ordNumCols > 0)
-		winstate->ordEqfunction =
-			execTuplesMatchPrepare(scanDesc,
-								   node->ordNumCols,
-								   node->ordColIdx,
-								   node->ordOperators,
-								   &winstate->ss.ps);
+		winstate->ordEqfunctions = execTuplesMatchPrepare(node->ordNumCols,
+														  node->ordOperators);
 
 	/*
 	 * WindowAgg nodes use aggvalues and aggnulls as well as Agg nodes.
@@ -2891,15 +2879,15 @@ are_peers(WindowAggState *winstate, TupleTableSlot *slot1,
 		  TupleTableSlot *slot2)
 {
 	WindowAgg  *node = (WindowAgg *) winstate->ss.ps.plan;
-	ExprContext *econtext = winstate->tmpcontext;
 
 	/* If no ORDER BY, all rows are peers with each other */
 	if (node->ordNumCols == 0)
 		return true;
 
-	econtext->ecxt_outertuple = slot1;
-	econtext->ecxt_innertuple = slot2;
-	return ExecQualAndReset(winstate->ordEqfunction, econtext);
+	return execTuplesMatch(slot1, slot2,
+						   node->ordNumCols, node->ordColIdx,
+						   winstate->ordEqfunctions,
+						   winstate->tmpcontext->ecxt_per_tuple_memory);
 }
 
 /*