Do execGrouping.c via expression eval machinery, take two.

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.

Large parts of this were previously committed (773aec7aa), but the
commit contained an omission around cross-type comparisons and was
thus reverted.

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

3 files changed, 25 insertions, 24 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..621e7c3dc46 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -113,26 +113,19 @@ 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,
+					  Oid **eqFuncOids,
 					  FmgrInfo **hashFunctions);
-extern TupleHashTable BuildTupleHashTable(int numCols, AttrNumber *keyColIdx,
-					FmgrInfo *eqfunctions,
+extern TupleHashTable BuildTupleHashTable(PlanState *parent,
+					TupleDesc inputDesc,
+					int numCols, AttrNumber *keyColIdx,
+					Oid *eqfuncoids,
 					FmgrInfo *hashfunctions,
 					long nbuckets, Size additionalsize,
 					MemoryContext tablecxt,
@@ -142,7 +135,7 @@ extern TupleHashEntry LookupTupleHashEntry(TupleHashTable hashtable,
 					 bool *isnew);
 extern TupleHashEntry FindTupleHashEntry(TupleHashTable hashtable,
 				   TupleTableSlot *slot,
-				   FmgrInfo *eqfunctions,
+				   ExprState *eqcomp,
 				   FmgrInfo *hashfunctions);
 
 /*
@@ -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 ldesc, TupleDesc rdesc,
+					   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..aa6ebaaf97d 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 */
 
@@ -290,7 +292,7 @@ typedef struct AggStatePerHashData
 	TupleHashIterator hashiter; /* for iterating through hash table */
 	TupleTableSlot *hashslot;	/* slot for loading hash table */
 	FmgrInfo   *hashfunctions;	/* per-grouping-field hash fns */
-	FmgrInfo   *eqfunctions;	/* per-grouping-field equality fns */
+	Oid		   *eqfuncoids;		/* per-grouping-field equality fns */
 	int			numCols;		/* number of hash key columns */
 	int			numhashGrpCols; /* number of columns in hash table */
 	int			largestGrpColIdx;	/* largest col required for hashing */