diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c
index 8340a66052..cc7c996718 100644
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -182,8 +182,8 @@ typedef struct
 {
 	void	   *tuple;			/* the tuple itself */
 	Datum		datum1;			/* value of first key column */
-	bool		isnull1;		/* is first key column NULL? */
 	int			srctape;		/* source tape number */
+	bool		isnull1;		/* is first key column NULL? */
 } SortTuple;
 
 /*
@@ -695,7 +695,7 @@ static void tuplesort_updatemax(Tuplesortstate *state);
 
 /* Used if first key's comparator is ssup_datum_unsigned_compare */
 static pg_attribute_always_inline int
-qsort_tuple_unsigned_compare(SortTuple *a, SortTuple *b, Tuplesortstate *state)
+qsort_tuple_unsigned_compare(const SortTuple *a, const SortTuple *b, Tuplesortstate *state)
 {
 	int			compare;
 
@@ -718,7 +718,7 @@ qsort_tuple_unsigned_compare(SortTuple *a, SortTuple *b, Tuplesortstate *state)
 #if SIZEOF_DATUM >= 8
 /* Used if first key's comparator is ssup_datum_signed_compare */
 static pg_attribute_always_inline int
-qsort_tuple_signed_compare(SortTuple *a, SortTuple *b, Tuplesortstate *state)
+qsort_tuple_signed_compare(const SortTuple *a, const SortTuple *b, Tuplesortstate *state)
 {
 	int			compare;
 
@@ -742,7 +742,7 @@ qsort_tuple_signed_compare(SortTuple *a, SortTuple *b, Tuplesortstate *state)
 
 /* Used if first key's comparator is ssup_datum_int32_compare */
 static pg_attribute_always_inline int
-qsort_tuple_int32_compare(SortTuple *a, SortTuple *b, Tuplesortstate *state)
+qsort_tuple_int32_compare(const SortTuple *a, const SortTuple *b, Tuplesortstate *state)
 {
 	int			compare;
 
@@ -972,10 +972,13 @@ tuplesort_begin_batch(Tuplesortstate *state)
 	 * generation.c context as this keeps allocations more compact with less
 	 * wastage.  Allocations are also slightly more CPU efficient.
 	 */
-	if (state->sortopt & TUPLESORT_ALLOWBOUNDED)
+	if (state->sortopt & TUPLESORT_ALLOWBOUNDED ||
+		(state->memtupsize & (state->memtupsize - 1)) == 0)
+	{
 		state->tuplecontext = AllocSetContextCreate(state->sortcontext,
 													"Caller tuples",
 													ALLOCSET_DEFAULT_SIZES);
+	}
 	else
 		state->tuplecontext = GenerationContextCreate(state->sortcontext,
 													  "Caller tuples",
@@ -4360,7 +4363,6 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 	/* Compare additional sort keys */
 	tuple1 = (IndexTuple) a->tuple;
 	tuple2 = (IndexTuple) b->tuple;
-	keysz = state->nKeys;
 	tupDes = RelationGetDescr(state->indexRel);
 
 	if (sortKey->abbrev_converter)
@@ -4380,6 +4382,7 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 		equal_hasnull = true;
 
 	sortKey++;
+	keysz = state->nKeys;
 	for (nkey = 2; nkey <= keysz; nkey++, sortKey++)
 	{
 		datum1 = index_getattr(tuple1, nkey, tupDes, &isnull1);
@@ -4444,15 +4447,19 @@ comparetup_index_btree(const SortTuple *a, const SortTuple *b,
 		BlockNumber blk1 = ItemPointerGetBlockNumber(&tuple1->t_tid);
 		BlockNumber blk2 = ItemPointerGetBlockNumber(&tuple2->t_tid);
 
-		if (blk1 != blk2)
-			return (blk1 < blk2) ? -1 : 1;
+		if (blk1 < blk2)
+			return -1;
+		else if (blk1 > blk2)
+			return 1;
 	}
 	{
 		OffsetNumber pos1 = ItemPointerGetOffsetNumber(&tuple1->t_tid);
 		OffsetNumber pos2 = ItemPointerGetOffsetNumber(&tuple2->t_tid);
 
-		if (pos1 != pos2)
-			return (pos1 < pos2) ? -1 : 1;
+		if (pos1 < pos2)
+			return -1;
+		else if (pos1 > pos2)
+			return 1;
 	}
 
 	/* ItemPointer values should never be equal */
@@ -4499,15 +4506,19 @@ comparetup_index_hash(const SortTuple *a, const SortTuple *b,
 		BlockNumber blk1 = ItemPointerGetBlockNumber(&tuple1->t_tid);
 		BlockNumber blk2 = ItemPointerGetBlockNumber(&tuple2->t_tid);
 
-		if (blk1 != blk2)
-			return (blk1 < blk2) ? -1 : 1;
+		if (blk1 < blk2)
+			return -1;
+		else if (blk1 > blk2)
+			return 1;
 	}
 	{
 		OffsetNumber pos1 = ItemPointerGetOffsetNumber(&tuple1->t_tid);
 		OffsetNumber pos2 = ItemPointerGetOffsetNumber(&tuple2->t_tid);
 
-		if (pos1 != pos2)
-			return (pos1 < pos2) ? -1 : 1;
+		if (pos1 < pos2)
+			return -1;
+		else if (pos1 > pos2)
+			return 1;
 	}
 
 	/* ItemPointer values should never be equal */
@@ -4642,25 +4653,25 @@ readtup_datum(Tuplesortstate *state, SortTuple *stup,
 	if (tuplen == 0)
 	{
 		/* it's NULL */
+		stup->tuple = NULL;
 		stup->datum1 = (Datum) 0;
 		stup->isnull1 = true;
-		stup->tuple = NULL;
 	}
 	else if (!state->tuples)
 	{
 		Assert(tuplen == sizeof(Datum));
+		stup->tuple = NULL;
 		LogicalTapeReadExact(tape, &stup->datum1, tuplen);
 		stup->isnull1 = false;
-		stup->tuple = NULL;
 	}
 	else
 	{
 		void	   *raddr = readtup_alloc(state, tuplen);
 
 		LogicalTapeReadExact(tape, raddr, tuplen);
+		stup->tuple = raddr;
 		stup->datum1 = PointerGetDatum(raddr);
 		stup->isnull1 = false;
-		stup->tuple = raddr;
 	}
 
 	if (state->sortopt & TUPLESORT_RANDOMACCESS)	/* need trailing length
diff --git a/src/include/lib/sort_template.h b/src/include/lib/sort_template.h
index 3122a93009..86ac216172 100644
--- a/src/include/lib/sort_template.h
+++ b/src/include/lib/sort_template.h
@@ -309,12 +309,12 @@ loop:
 	for (pm = a + ST_POINTER_STEP; pm < a + n * ST_POINTER_STEP;
 		 pm += ST_POINTER_STEP)
 	{
-		DO_CHECK_FOR_INTERRUPTS();
 		if (DO_COMPARE(pm - ST_POINTER_STEP, pm) > 0)
 		{
 			presorted = 0;
 			break;
 		}
+		DO_CHECK_FOR_INTERRUPTS();
 	}
 	if (presorted)
 		return;