Do execGrouping.c via expression eval machinery.

This has a performance benefit on own, although not hugely so. The
primary benefit is that it will allow for to JIT tuple deforming and
comparator invocations.

Author: Andres Freund
Discussion: https://postgr.es/m/20171129080934.amqqkke2zjtekd4t@alap3.anarazel.de

1 files changed, 25 insertions, 13 deletions

diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index f6412576f40..1c807a82922 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -1272,12 +1272,13 @@ 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 (!execTuplesMatch(winstate->first_part_slot,
-								 outerslot,
-								 node->partNumCols, node->partColIdx,
-								 winstate->partEqfunctions,
-								 winstate->tmpcontext->ecxt_per_tuple_memory))
+			if (!ExecQualAndReset(winstate->partEqfunction, econtext))
 			{
 				/*
 				 * end of partition; copy the tuple for the next cycle.
@@ -2245,6 +2246,7 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 				wfuncno,
 				numaggs,
 				aggno;
+	TupleDesc	scanDesc;
 	ListCell   *l;
 
 	/* check for unsupported flags */
@@ -2327,6 +2329,7 @@ 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);
@@ -2351,11 +2354,20 @@ ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags)
 
 	/* Set up data for comparing tuples */
 	if (node->partNumCols > 0)
-		winstate->partEqfunctions = execTuplesMatchPrepare(node->partNumCols,
-														   node->partOperators);
+		winstate->partEqfunction =
+			execTuplesMatchPrepare(scanDesc,
+								   node->partNumCols,
+								   node->partColIdx,
+								   node->partOperators,
+								   &winstate->ss.ps);
+
 	if (node->ordNumCols > 0)
-		winstate->ordEqfunctions = execTuplesMatchPrepare(node->ordNumCols,
-														  node->ordOperators);
+		winstate->ordEqfunction =
+			execTuplesMatchPrepare(scanDesc,
+								   node->ordNumCols,
+								   node->ordColIdx,
+								   node->ordOperators,
+								   &winstate->ss.ps);
 
 	/*
 	 * WindowAgg nodes use aggvalues and aggnulls as well as Agg nodes.
@@ -2879,15 +2891,15 @@ 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;
 
-	return execTuplesMatch(slot1, slot2,
-						   node->ordNumCols, node->ordColIdx,
-						   winstate->ordEqfunctions,
-						   winstate->tmpcontext->ecxt_per_tuple_memory);
+	econtext->ecxt_outertuple = slot1;
+	econtext->ecxt_innertuple = slot2;
+	return ExecQualAndReset(winstate->ordEqfunction, econtext);
 }
 
 /*