Use the sortsupport infrastructure in more cases.

This removes some fmgr overhead from cases such as btree index builds.

Peter Geoghegan, reviewed by Andreas Karlsson and me.

src/backend/access/nbtree/nbtsort.c

@@ -686,6 +686,7 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 	int			i,
 				keysz = RelationGetNumberOfAttributes(wstate->index);
 	ScanKey		indexScanKey = NULL;
+	SortSupport sortKeys;
 
 	if (merge)
 	{
@@ -701,6 +702,31 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 										true, &should_free2);
 		indexScanKey = _bt_mkscankey_nodata(wstate->index);
 
+		/* Prepare SortSupport data for each column */
+		sortKeys = (SortSupport) palloc0(keysz * sizeof(SortSupportData));
+
+		for (i = 0; i < keysz; i++)
+		{
+			SortSupport sortKey = sortKeys + i;
+			ScanKey		scanKey = indexScanKey + i;
+			int16		strategy;
+
+			sortKey->ssup_cxt = CurrentMemoryContext;
+			sortKey->ssup_collation = scanKey->sk_collation;
+			sortKey->ssup_nulls_first =
+				(scanKey->sk_flags & SK_BT_NULLS_FIRST) != 0;
+			sortKey->ssup_attno = scanKey->sk_attno;
+
+			AssertState(sortKey->ssup_attno != 0);
+
+			strategy = (scanKey->sk_flags & SK_BT_DESC) != 0 ?
+				BTGreaterStrategyNumber : BTLessStrategyNumber;
+
+			PrepareSortSupportFromIndexRel(wstate->index, strategy, sortKey);
+		}
+
+		_bt_freeskey(indexScanKey);
+
 		for (;;)
 		{
 			load1 = true;		/* load BTSpool next ? */
@@ -713,43 +739,20 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 			{
 				for (i = 1; i <= keysz; i++)
 				{
-					ScanKey		entry;
+					SortSupport	entry;
 					Datum		attrDatum1,
 								attrDatum2;
 					bool		isNull1,
 								isNull2;
 					int32		compare;
 
-					entry = indexScanKey + i - 1;
+					entry = sortKeys + i - 1;
 					attrDatum1 = index_getattr(itup, i, tupdes, &isNull1);
 					attrDatum2 = index_getattr(itup2, i, tupdes, &isNull2);
-					if (isNull1)
-					{
-						if (isNull2)
-							compare = 0;		/* NULL "=" NULL */
-						else if (entry->sk_flags & SK_BT_NULLS_FIRST)
-							compare = -1;		/* NULL "<" NOT_NULL */
-						else
-							compare = 1;		/* NULL ">" NOT_NULL */
-					}
-					else if (isNull2)
-					{
-						if (entry->sk_flags & SK_BT_NULLS_FIRST)
-							compare = 1;		/* NOT_NULL ">" NULL */
-						else
-							compare = -1;		/* NOT_NULL "<" NULL */
-					}
-					else
-					{
-						compare =
-							DatumGetInt32(FunctionCall2Coll(&entry->sk_func,
-														 entry->sk_collation,
-															attrDatum1,
-															attrDatum2));
-
-						if (entry->sk_flags & SK_BT_DESC)
-							compare = -compare;
-					}
+
+					compare = ApplySortComparator(attrDatum1, isNull1,
+												  attrDatum2, isNull2,
+												  entry);
 					if (compare > 0)
 					{
 						load1 = false;
@@ -783,7 +786,7 @@ _bt_load(BTWriteState *wstate, BTSpool *btspool, BTSpool *btspool2)
 												true, &should_free2);
 			}
 		}
-		_bt_freeskey(indexScanKey);
+		pfree(sortKeys);
 	}
 	else
 	{

src/backend/utils/sort/sortsupport.c

@@ -21,6 +21,7 @@
 #include "access/nbtree.h"
 #include "fmgr.h"
 #include "utils/lsyscache.h"
+#include "utils/rel.h"
 #include "utils/sortsupport.h"
 
 
@@ -86,28 +87,14 @@ PrepareSortSupportComparisonShim(Oid cmpFunc, SortSupport ssup)
 }
 
 /*
- * Fill in SortSupport given an ordering operator (btree "<" or ">" operator).
- *
- * Caller must previously have zeroed the SortSupportData structure and then
- * filled in ssup_cxt, ssup_collation, and ssup_nulls_first.  This will fill
- * in ssup_reverse as well as the comparator function pointer.
+ * Look up and call sortsupport function to setup SortSupport comparator;
+ * or if no such function exists or it declines to set up the appropriate
+ * state, prepare a suitable shim.
  */
-void
-PrepareSortSupportFromOrderingOp(Oid orderingOp, SortSupport ssup)
+static void
+FinishSortSupportFunction(Oid opfamily, Oid opcintype, SortSupport ssup)
 {
 	Oid			sortSupportFunction;
-	Oid			opfamily;
-	Oid			opcintype;
-	int16		strategy;
-
-	Assert(ssup->comparator == NULL);
-
-	/* Find the operator in pg_amop */
-	if (!get_ordering_op_properties(orderingOp, &opfamily, &opcintype,
-									&strategy))
-		elog(ERROR, "operator %u is not a valid ordering operator",
-			 orderingOp);
-	ssup->ssup_reverse = (strategy == BTGreaterStrategyNumber);
 
 	/* Look for a sort support function */
 	sortSupportFunction = get_opfamily_proc(opfamily, opcintype, opcintype,
@@ -136,3 +123,57 @@ PrepareSortSupportFromOrderingOp(Oid orderingOp, SortSupport ssup)
 		PrepareSortSupportComparisonShim(sortFunction, ssup);
 	}
 }
+
+/*
+ * Fill in SortSupport given an ordering operator (btree "<" or ">" operator).
+ *
+ * Caller must previously have zeroed the SortSupportData structure and then
+ * filled in ssup_cxt, ssup_collation, and ssup_nulls_first.  This will fill
+ * in ssup_reverse as well as the comparator function pointer.
+ */
+void
+PrepareSortSupportFromOrderingOp(Oid orderingOp, SortSupport ssup)
+{
+	Oid			opfamily;
+	Oid			opcintype;
+	int16		strategy;
+
+	Assert(ssup->comparator == NULL);
+
+	/* Find the operator in pg_amop */
+	if (!get_ordering_op_properties(orderingOp, &opfamily, &opcintype,
+									&strategy))
+		elog(ERROR, "operator %u is not a valid ordering operator",
+			 orderingOp);
+	ssup->ssup_reverse = (strategy == BTGreaterStrategyNumber);
+
+	FinishSortSupportFunction(opfamily, opcintype, ssup);
+}
+
+/*
+ * Fill in SortSupport given an index relation, attribute, and strategy.
+ *
+ * Caller must previously have zeroed the SortSupportData structure and then
+ * filled in ssup_cxt, ssup_attno, ssup_collation, and ssup_nulls_first.  This
+ * will fill in ssup_reverse (based on the supplied strategy), as well as the
+ * comparator function pointer.
+ */
+void
+PrepareSortSupportFromIndexRel(Relation indexRel, int16 strategy,
+							   SortSupport ssup)
+{
+	Oid			opfamily = indexRel->rd_opfamily[ssup->ssup_attno - 1];
+	Oid			opcintype = indexRel->rd_opcintype[ssup->ssup_attno - 1];
+
+	Assert(ssup->comparator == NULL);
+
+	/* Find the operator in pg_amop */
+	if (indexRel->rd_rel->relam != BTREE_AM_OID)
+		elog(ERROR, "unexpected non-btree AM: %u", indexRel->rd_rel->relam);
+	if (strategy != BTGreaterStrategyNumber &&
+		strategy != BTLessStrategyNumber)
+		elog(ERROR, "unexpected sort support strategy: %d", strategy);
+	ssup->ssup_reverse = (strategy == BTGreaterStrategyNumber);
+
+	FinishSortSupportFunction(opfamily, opcintype, ssup);
+}

src/backend/utils/sort/tuplesort.c

@@ -256,13 +256,6 @@ struct Tuplesortstate
 	void		(*readtup) (Tuplesortstate *state, SortTuple *stup,
 										int tapenum, unsigned int len);
 
-	/*
-	 * Function to reverse the sort direction from its current state. (We
-	 * could dispense with this if we wanted to enforce that all variants
-	 * represent the sort key information alike.)
-	 */
-	void		(*reversedirection) (Tuplesortstate *state);
-
 	/*
 	 * This array holds the tuples now in sort memory.  If we are in state
 	 * INITIAL, the tuples are in no particular order; if we are in state
@@ -340,8 +333,9 @@ struct Tuplesortstate
 	bool		markpos_eof;	/* saved "eof_reached" */
 
 	/*
-	 * These variables are specific to the MinimalTuple case; they are set by
-	 * tuplesort_begin_heap and used only by the MinimalTuple routines.
+	 * The sortKeys variable is used by every case other than the hash index
+	 * case; it is set by tuplesort_begin_xxx.  tupDesc is only used by the
+	 * MinimalTuple and CLUSTER routines, though.
 	 */
 	TupleDesc	tupDesc;
 	SortSupport sortKeys;		/* array of length nKeys */
@@ -354,8 +348,7 @@ struct Tuplesortstate
 
 	/*
 	 * These variables are specific to the CLUSTER case; they are set by
-	 * tuplesort_begin_cluster.  Note CLUSTER also uses tupDesc and
-	 * indexScanKey.
+	 * tuplesort_begin_cluster.
 	 */
 	IndexInfo  *indexInfo;		/* info about index being used for reference */
 	EState	   *estate;			/* for evaluating index expressions */
@@ -368,7 +361,6 @@ struct Tuplesortstate
 	Relation	indexRel;		/* index being built */
 
 	/* These are specific to the index_btree subcase: */
-	ScanKey		indexScanKey;
 	bool		enforceUnique;	/* complain if we find duplicate tuples */
 
 	/* These are specific to the index_hash subcase: */
@@ -395,7 +387,6 @@ struct Tuplesortstate
 #define COPYTUP(state,stup,tup) ((*(state)->copytup) (state, stup, tup))
 #define WRITETUP(state,tape,stup)	((*(state)->writetup) (state, tape, stup))
 #define READTUP(state,stup,tape,len) ((*(state)->readtup) (state, stup, tape, len))
-#define REVERSEDIRECTION(state) ((*(state)->reversedirection) (state))
 #define LACKMEM(state)		((state)->availMem < 0)
 #define USEMEM(state,amt)	((state)->availMem -= (amt))
 #define FREEMEM(state,amt)	((state)->availMem += (amt))
@@ -464,6 +455,7 @@ static void sort_bounded_heap(Tuplesortstate *state);
 static void tuplesort_heap_insert(Tuplesortstate *state, SortTuple *tuple,
 					  int tupleindex, bool checkIndex);
 static void tuplesort_heap_siftup(Tuplesortstate *state, bool checkIndex);
+static void reversedirection(Tuplesortstate *state);
 static unsigned int getlen(Tuplesortstate *state, int tapenum, bool eofOK);
 static void markrunend(Tuplesortstate *state, int tapenum);
 static int comparetup_heap(const SortTuple *a, const SortTuple *b,
@@ -473,7 +465,6 @@ static void writetup_heap(Tuplesortstate *state, int tapenum,
 			  SortTuple *stup);
 static void readtup_heap(Tuplesortstate *state, SortTuple *stup,
 			 int tapenum, unsigned int len);
-static void reversedirection_heap(Tuplesortstate *state);
 static int comparetup_cluster(const SortTuple *a, const SortTuple *b,
 				   Tuplesortstate *state);
 static void copytup_cluster(Tuplesortstate *state, SortTuple *stup, void *tup);
@@ -490,8 +481,6 @@ static void writetup_index(Tuplesortstate *state, int tapenum,
 			   SortTuple *stup);
 static void readtup_index(Tuplesortstate *state, SortTuple *stup,
 			  int tapenum, unsigned int len);
-static void reversedirection_index_btree(Tuplesortstate *state);
-static void reversedirection_index_hash(Tuplesortstate *state);
 static int comparetup_datum(const SortTuple *a, const SortTuple *b,
 				 Tuplesortstate *state);
 static void copytup_datum(Tuplesortstate *state, SortTuple *stup, void *tup);
@@ -499,7 +488,6 @@ static void writetup_datum(Tuplesortstate *state, int tapenum,
 			   SortTuple *stup);
 static void readtup_datum(Tuplesortstate *state, SortTuple *stup,
 			  int tapenum, unsigned int len);
-static void reversedirection_datum(Tuplesortstate *state);
 static void free_sort_tuple(Tuplesortstate *state, SortTuple *stup);
 
 /*
@@ -629,7 +617,6 @@ tuplesort_begin_heap(TupleDesc tupDesc,
 	state->copytup = copytup_heap;
 	state->writetup = writetup_heap;
 	state->readtup = readtup_heap;
-	state->reversedirection = reversedirection_heap;
 
 	state->tupDesc = tupDesc;	/* assume we need not copy tupDesc */
 
@@ -665,7 +652,9 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 						int workMem, bool randomAccess)
 {
 	Tuplesortstate *state = tuplesort_begin_common(workMem, randomAccess);
+	ScanKey			indexScanKey;
 	MemoryContext oldcontext;
+	int				i;
 
 	Assert(indexRel->rd_rel->relam == BTREE_AM_OID);
 
@@ -691,13 +680,13 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 	state->copytup = copytup_cluster;
 	state->writetup = writetup_cluster;
 	state->readtup = readtup_cluster;
-	state->reversedirection = reversedirection_index_btree;
 
 	state->indexInfo = BuildIndexInfo(indexRel);
-	state->indexScanKey = _bt_mkscankey_nodata(indexRel);
 
 	state->tupDesc = tupDesc;	/* assume we need not copy tupDesc */
 
+	indexScanKey = _bt_mkscankey_nodata(indexRel);
+
 	if (state->indexInfo->ii_Expressions != NULL)
 	{
 		TupleTableSlot *slot;
@@ -715,6 +704,32 @@ tuplesort_begin_cluster(TupleDesc tupDesc,
 		econtext->ecxt_scantuple = slot;
 	}
 
+	/* Prepare SortSupport data for each column */
+	state->sortKeys = (SortSupport) palloc0(state->nKeys *
+											sizeof(SortSupportData));
+
+	for (i = 0; i < state->nKeys; i++)
+	{
+		SortSupport sortKey = state->sortKeys + i;
+		ScanKey		scanKey = indexScanKey + i;
+		int16		strategy;
+
+		sortKey->ssup_cxt = CurrentMemoryContext;
+		sortKey->ssup_collation = scanKey->sk_collation;
+		sortKey->ssup_nulls_first =
+			(scanKey->sk_flags & SK_BT_NULLS_FIRST) != 0;
+		sortKey->ssup_attno = scanKey->sk_attno;
+
+		AssertState(sortKey->ssup_attno != 0);
+
+		strategy = (scanKey->sk_flags & SK_BT_DESC) != 0 ?
+			BTGreaterStrategyNumber : BTLessStrategyNumber;
+
+		PrepareSortSupportFromIndexRel(indexRel, strategy, sortKey);
+	}
+
+	_bt_freeskey(indexScanKey);
+
 	MemoryContextSwitchTo(oldcontext);
 
 	return state;
@@ -727,7 +742,9 @@ tuplesort_begin_index_btree(Relation heapRel,
 							int workMem, bool randomAccess)
 {
 	Tuplesortstate *state = tuplesort_begin_common(workMem, randomAccess);
+	ScanKey			indexScanKey;
 	MemoryContext oldcontext;
+	int				i;
 
 	oldcontext = MemoryContextSwitchTo(state->sortcontext);
 
@@ -751,13 +768,40 @@ tuplesort_begin_index_btree(Relation heapRel,
 	state->copytup = copytup_index;
 	state->writetup = writetup_index;
 	state->readtup = readtup_index;
-	state->reversedirection = reversedirection_index_btree;
 
 	state->heapRel = heapRel;
 	state->indexRel = indexRel;
-	state->indexScanKey = _bt_mkscankey_nodata(indexRel);
 	state->enforceUnique = enforceUnique;
 
+	indexScanKey = _bt_mkscankey_nodata(indexRel);
+	state->nKeys = RelationGetNumberOfAttributes(indexRel);
+
+	/* Prepare SortSupport data for each column */
+	state->sortKeys = (SortSupport) palloc0(state->nKeys *
+											sizeof(SortSupportData));
+
+	for (i = 0; i < state->nKeys; i++)
+	{
+		SortSupport sortKey = state->sortKeys + i;
+		ScanKey		scanKey = indexScanKey + i;
+		int16		strategy;
+
+		sortKey->ssup_cxt = CurrentMemoryContext;
+		sortKey->ssup_collation = scanKey->sk_collation;
+		sortKey->ssup_nulls_first =
+			(scanKey->sk_flags & SK_BT_NULLS_FIRST) != 0;
+		sortKey->ssup_attno = scanKey->sk_attno;
+
+		AssertState(sortKey->ssup_attno != 0);
+
+		strategy = (scanKey->sk_flags & SK_BT_DESC) != 0 ?
+			BTGreaterStrategyNumber : BTLessStrategyNumber;
+
+		PrepareSortSupportFromIndexRel(indexRel, strategy, sortKey);
+	}
+
+	_bt_freeskey(indexScanKey);
+
 	MemoryContextSwitchTo(oldcontext);
 
 	return state;
@@ -788,7 +832,6 @@ tuplesort_begin_index_hash(Relation heapRel,
 	state->copytup = copytup_index;
 	state->writetup = writetup_index;
 	state->readtup = readtup_index;
-	state->reversedirection = reversedirection_index_hash;
 
 	state->heapRel = heapRel;
 	state->indexRel = indexRel;
@@ -831,7 +874,6 @@ tuplesort_begin_datum(Oid datumType, Oid sortOperator, Oid sortCollation,
 	state->copytup = copytup_datum;
 	state->writetup = writetup_datum;
 	state->readtup = readtup_datum;
-	state->reversedirection = reversedirection_datum;
 
 	state->datumType = datumType;
 
@@ -2599,7 +2641,7 @@ make_bounded_heap(Tuplesortstate *state)
 	Assert(tupcount >= state->bound);
 
 	/* Reverse sort direction so largest entry will be at root */
-	REVERSEDIRECTION(state);
+	reversedirection(state);
 
 	state->memtupcount = 0;		/* make the heap empty */
 	for (i = 0; i < tupcount; i++)
@@ -2663,7 +2705,7 @@ sort_bounded_heap(Tuplesortstate *state)
 	 * Reverse sort direction back to the original state.  This is not
 	 * actually necessary but seems like a good idea for tidiness.
 	 */
-	REVERSEDIRECTION(state);
+	reversedirection(state);
 
 	state->status = TSS_SORTEDINMEM;
 	state->boundUsed = true;
@@ -2753,6 +2795,24 @@ tuplesort_heap_siftup(Tuplesortstate *state, bool checkIndex)
 	memtuples[i] = *tuple;
 }
 
+/*
+ * Function to reverse the sort direction from its current state
+ *
+ * It is not safe to call this when performing hash tuplesorts
+ */
+static void
+reversedirection(Tuplesortstate *state)
+{
+	SortSupport sortKey = state->sortKeys;
+	int			nkey;
+
+	for (nkey = 0; nkey < state->nKeys; nkey++, sortKey++)
+	{
+		sortKey->ssup_reverse = !sortKey->ssup_reverse;
+		sortKey->ssup_nulls_first = !sortKey->ssup_nulls_first;
+	}
+}
+
 
 /*
  * Tape interface routines
@@ -2780,73 +2840,6 @@ markrunend(Tuplesortstate *state, int tapenum)
 }
 
 
-/*
- * Inline-able copy of FunctionCall2Coll() to save some cycles in sorting.
- */
-static inline Datum
-myFunctionCall2Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2)
-{
-	FunctionCallInfoData fcinfo;
-	Datum		result;
-
-	InitFunctionCallInfoData(fcinfo, flinfo, 2, collation, NULL, NULL);
-
-	fcinfo.arg[0] = arg1;
-	fcinfo.arg[1] = arg2;
-	fcinfo.argnull[0] = false;
-	fcinfo.argnull[1] = false;
-
-	result = FunctionCallInvoke(&fcinfo);
-
-	/* Check for null result, since caller is clearly not expecting one */
-	if (fcinfo.isnull)
-		elog(ERROR, "function %u returned NULL", fcinfo.flinfo->fn_oid);
-
-	return result;
-}
-
-/*
- * Apply a sort function (by now converted to fmgr lookup form)
- * and return a 3-way comparison result.  This takes care of handling
- * reverse-sort and NULLs-ordering properly.  We assume that DESC and
- * NULLS_FIRST options are encoded in sk_flags the same way btree does it.
- */
-static inline int32
-inlineApplySortFunction(FmgrInfo *sortFunction, int sk_flags, Oid collation,
-						Datum datum1, bool isNull1,
-						Datum datum2, bool isNull2)
-{
-	int32		compare;
-
-	if (isNull1)
-	{
-		if (isNull2)
-			compare = 0;		/* NULL "=" NULL */
-		else if (sk_flags & SK_BT_NULLS_FIRST)
-			compare = -1;		/* NULL "<" NOT_NULL */
-		else
-			compare = 1;		/* NULL ">" NOT_NULL */
-	}
-	else if (isNull2)
-	{
-		if (sk_flags & SK_BT_NULLS_FIRST)
-			compare = 1;		/* NOT_NULL ">" NULL */
-		else
-			compare = -1;		/* NOT_NULL "<" NULL */
-	}
-	else
-	{
-		compare = DatumGetInt32(myFunctionCall2Coll(sortFunction, collation,
-													datum1, datum2));
-
-		if (sk_flags & SK_BT_DESC)
-			compare = -compare;
-	}
-
-	return compare;
-}
-
-
 /*
  * Routines specialized for HeapTuple (actually MinimalTuple) case
  */
@@ -2972,20 +2965,6 @@ readtup_heap(Tuplesortstate *state, SortTuple *stup,
 								&stup->isnull1);
 }
 
-static void
-reversedirection_heap(Tuplesortstate *state)
-{
-	SortSupport sortKey = state->sortKeys;
-	int			nkey;
-
-	for (nkey = 0; nkey < state->nKeys; nkey++, sortKey++)
-	{
-		sortKey->ssup_reverse = !sortKey->ssup_reverse;
-		sortKey->ssup_nulls_first = !sortKey->ssup_nulls_first;
-	}
-}
-
-
 /*
  * Routines specialized for the CLUSTER case (HeapTuple data, with
  * comparisons per a btree index definition)
@@ -2995,7 +2974,7 @@ static int
 comparetup_cluster(const SortTuple *a, const SortTuple *b,
 				   Tuplesortstate *state)
 {
-	ScanKey		scanKey = state->indexScanKey;
+	SortSupport	sortKey = state->sortKeys;
 	HeapTuple	ltup;
 	HeapTuple	rtup;
 	TupleDesc	tupDesc;
@@ -3005,14 +2984,13 @@ comparetup_cluster(const SortTuple *a, const SortTuple *b,
 	/* Compare the leading sort key, if it's simple */
 	if (state->indexInfo->ii_KeyAttrNumbers[0] != 0)
 	{
-		compare = inlineApplySortFunction(&scanKey->sk_func, scanKey->sk_flags,
-										  scanKey->sk_collation,
-										  a->datum1, a->isnull1,
-										  b->datum1, b->isnull1);
+		compare = ApplySortComparator(a->datum1, a->isnull1,
+									  b->datum1, b->isnull1,
+									  sortKey);
 		if (compare != 0 || state->nKeys == 1)
 			return compare;
 		/* Compare additional columns the hard way */
-		scanKey++;
+		sortKey++;
 		nkey = 1;
 	}
 	else
@@ -3030,7 +3008,7 @@ comparetup_cluster(const SortTuple *a, const SortTuple *b,
 		/* If not expression index, just compare the proper heap attrs */
 		tupDesc = state->tupDesc;
 
-		for (; nkey < state->nKeys; nkey++, scanKey++)
+		for (; nkey < state->nKeys; nkey++, sortKey++)
 		{
 			AttrNumber	attno = state->indexInfo->ii_KeyAttrNumbers[nkey];
 			Datum		datum1,
@@ -3041,11 +3019,9 @@ comparetup_cluster(const SortTuple *a, const SortTuple *b,
 			datum1 = heap_getattr(ltup, attno, tupDesc, &isnull1);
 			datum2 = heap_getattr(rtup, attno, tupDesc, &isnull2);
 
-			compare = inlineApplySortFunction(&scanKey->sk_func,
-											  scanKey->sk_flags,
-											  scanKey->sk_collation,
-											  datum1, isnull1,
-											  datum2, isnull2);
+			compare = ApplySortComparator(datum1, isnull1,
+										  datum2, isnull2,
+										  sortKey);
 			if (compare != 0)
 				return compare;
 		}
@@ -3077,15 +3053,13 @@ comparetup_cluster(const SortTuple *a, const SortTuple *b,
 		FormIndexDatum(state->indexInfo, ecxt_scantuple, state->estate,
 					   r_index_values, r_index_isnull);
 
-		for (; nkey < state->nKeys; nkey++, scanKey++)
+		for (; nkey < state->nKeys; nkey++, sortKey++)
 		{
-			compare = inlineApplySortFunction(&scanKey->sk_func,
-											  scanKey->sk_flags,
-											  scanKey->sk_collation,
-											  l_index_values[nkey],
-											  l_index_isnull[nkey],
-											  r_index_values[nkey],
-											  r_index_isnull[nkey]);
+			compare = ApplySortComparator(l_index_values[nkey],
+										  l_index_isnull[nkey],
+										  r_index_values[nkey],
+										  r_index_isnull[nkey],
+										  sortKey);
 			if (compare != 0)
 				return compare;
 		}
@@ -3180,7 +3154,7 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 	 * is also special handling for enforcing uniqueness, and special treatment
 	 * for equal keys at the end.
 	 */
-	ScanKey		scanKey = state->indexScanKey;
+	SortSupport	sortKey = state->sortKeys;
 	IndexTuple	tuple1;
 	IndexTuple	tuple2;
 	int			keysz;
@@ -3190,10 +3164,9 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 	int32		compare;
 
 	/* Compare the leading sort key */
-	compare = inlineApplySortFunction(&scanKey->sk_func, scanKey->sk_flags,
-									  scanKey->sk_collation,
-									  a->datum1, a->isnull1,
-									  b->datum1, b->isnull1);
+	compare = ApplySortComparator(a->datum1, a->isnull1,
+								  b->datum1, b->isnull1,
+								  sortKey);
 	if (compare != 0)
 		return compare;
 
@@ -3206,8 +3179,8 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 	tuple2 = (IndexTuple) b->tuple;
 	keysz = state->nKeys;
 	tupDes = RelationGetDescr(state->indexRel);
-	scanKey++;
-	for (nkey = 2; nkey <= keysz; nkey++, scanKey++)
+	sortKey++;
+	for (nkey = 2; nkey <= keysz; nkey++, sortKey++)
 	{
 		Datum		datum1,
 					datum2;
@@ -3217,10 +3190,9 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 		datum1 = index_getattr(tuple1, nkey, tupDes, &isnull1);
 		datum2 = index_getattr(tuple2, nkey, tupDes, &isnull2);
 
-		compare = inlineApplySortFunction(&scanKey->sk_func, scanKey->sk_flags,
-										  scanKey->sk_collation,
-										  datum1, isnull1,
-										  datum2, isnull2);
+		compare = ApplySortComparator(datum1, isnull1,
+									  datum2, isnull2,
+									  sortKey);
 		if (compare != 0)
 			return compare;		/* done when we find unequal attributes */
 
@@ -3394,26 +3366,6 @@ readtup_index(Tuplesortstate *state, SortTuple *stup,
 								 &stup->isnull1);
 }
 
-static void
-reversedirection_index_btree(Tuplesortstate *state)
-{
-	ScanKey		scanKey = state->indexScanKey;
-	int			nkey;
-
-	for (nkey = 0; nkey < state->nKeys; nkey++, scanKey++)
-	{
-		scanKey->sk_flags ^= (SK_BT_DESC | SK_BT_NULLS_FIRST);
-	}
-}
-
-static void
-reversedirection_index_hash(Tuplesortstate *state)
-{
-	/* We don't support reversing direction in a hash index sort */
-	elog(ERROR, "reversedirection_index_hash is not implemented");
-}
-
-
 /*
  * Routines specialized for DatumTuple case
  */
@@ -3512,13 +3464,6 @@ readtup_datum(Tuplesortstate *state, SortTuple *stup,
 							 &tuplen, sizeof(tuplen));
 }
 
-static void
-reversedirection_datum(Tuplesortstate *state)
-{
-	state->onlyKey->ssup_reverse = !state->onlyKey->ssup_reverse;
-	state->onlyKey->ssup_nulls_first = !state->onlyKey->ssup_nulls_first;
-}
-
 /*
  * Convenience routine to free a tuple previously loaded into sort memory
  */

src/include/utils/sortsupport.h

@@ -48,6 +48,7 @@
 #define SORTSUPPORT_H
 
 #include "access/attnum.h"
+#include "utils/relcache.h"
 
 typedef struct SortSupportData *SortSupport;
 
@@ -152,5 +153,7 @@ ApplySortComparator(Datum datum1, bool isNull1,
 /* Other functions in utils/sort/sortsupport.c */
 extern void PrepareSortSupportComparisonShim(Oid cmpFunc, SortSupport ssup);
 extern void PrepareSortSupportFromOrderingOp(Oid orderingOp, SortSupport ssup);
+extern void PrepareSortSupportFromIndexRel(Relation indexRel, int16 strategy,
+										   SortSupport ssup);
 
 #endif   /* SORTSUPPORT_H */