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

3 files changed, 21 insertions, 20 deletions

diff --git a/src/include/executor/execExpr.h b/src/include/executor/execExpr.h
index 117fc892f4b..0cab431f656 100644
--- a/src/include/executor/execExpr.h
+++ b/src/include/executor/execExpr.h
@@ -148,6 +148,7 @@ typedef enum ExprEvalOp
 	/* evaluate assorted special-purpose expression types */
 	EEOP_IOCOERCE,
 	EEOP_DISTINCT,
+	EEOP_NOT_DISTINCT,
 	EEOP_NULLIF,
 	EEOP_SQLVALUEFUNCTION,
 	EEOP_CURRENTOFEXPR,
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 1d824eff361..f648af27898 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -113,25 +113,18 @@ extern bool execCurrentOf(CurrentOfExpr *cexpr,
 /*
  * prototypes from functions in execGrouping.c
  */
-extern bool execTuplesMatch(TupleTableSlot *slot1,
-				TupleTableSlot *slot2,
-				int numCols,
-				AttrNumber *matchColIdx,
-				FmgrInfo *eqfunctions,
-				MemoryContext evalContext);
-extern bool execTuplesUnequal(TupleTableSlot *slot1,
-				  TupleTableSlot *slot2,
-				  int numCols,
-				  AttrNumber *matchColIdx,
-				  FmgrInfo *eqfunctions,
-				  MemoryContext evalContext);
-extern FmgrInfo *execTuplesMatchPrepare(int numCols,
-					   Oid *eqOperators);
+extern ExprState *execTuplesMatchPrepare(TupleDesc desc,
+					   int numCols,
+					   AttrNumber *keyColIdx,
+					   Oid *eqOperators,
+					   PlanState *parent);
 extern void execTuplesHashPrepare(int numCols,
 					  Oid *eqOperators,
 					  FmgrInfo **eqFunctions,
 					  FmgrInfo **hashFunctions);
-extern TupleHashTable BuildTupleHashTable(int numCols, AttrNumber *keyColIdx,
+extern TupleHashTable BuildTupleHashTable(PlanState *parent,
+					TupleDesc inputDesc,
+					int numCols, AttrNumber *keyColIdx,
 					FmgrInfo *eqfunctions,
 					FmgrInfo *hashfunctions,
 					long nbuckets, Size additionalsize,
@@ -257,6 +250,11 @@ extern ExprState *ExecInitCheck(List *qual, PlanState *parent);
 extern List *ExecInitExprList(List *nodes, PlanState *parent);
 extern ExprState *ExecBuildAggTrans(AggState *aggstate, struct AggStatePerPhaseData *phase,
 				  bool doSort, bool doHash);
+extern ExprState *ExecBuildGroupingEqual(TupleDesc desc,
+					   int numCols,
+					   AttrNumber *keyColIdx,
+					   Oid *eqfunctions,
+					   PlanState *parent);
 extern ProjectionInfo *ExecBuildProjectionInfo(List *targetList,
 						ExprContext *econtext,
 						TupleTableSlot *slot,
diff --git a/src/include/executor/nodeAgg.h b/src/include/executor/nodeAgg.h
index 3b06db86fd8..24be7d2daa8 100644
--- a/src/include/executor/nodeAgg.h
+++ b/src/include/executor/nodeAgg.h
@@ -102,11 +102,12 @@ typedef struct AggStatePerTransData
 	bool	   *sortNullsFirst;
 
 	/*
-	 * fmgr lookup data for input columns' equality operators --- only
-	 * set/used when aggregate has DISTINCT flag.  Note that these are in
-	 * order of sort column index, not parameter index.
+	 * Comparators for input columns --- only set/used when aggregate has
+	 * DISTINCT flag. equalfnOne version is used for single-column
+	 * commparisons, equalfnMulti for the case of multiple columns.
 	 */
-	FmgrInfo   *equalfns;		/* array of length numDistinctCols */
+	FmgrInfo	equalfnOne;
+	ExprState  *equalfnMulti;
 
 	/*
 	 * initial value from pg_aggregate entry
@@ -270,7 +271,8 @@ typedef struct AggStatePerPhaseData
 	int			numsets;		/* number of grouping sets (or 0) */
 	int		   *gset_lengths;	/* lengths of grouping sets */
 	Bitmapset **grouped_cols;	/* column groupings for rollup */
-	FmgrInfo   *eqfunctions;	/* per-grouping-field equality fns */
+	ExprState **eqfunctions;	/* expression returning equality, indexed by
+								 * nr of cols to compare */
 	Agg		   *aggnode;		/* Agg node for phase data */
 	Sort	   *sortnode;		/* Sort node for input ordering for phase */