diff --git a/src/backend/utils/sort/tuplestore.c b/src/backend/utils/sort/tuplestore.c
index 444c8e25c2..03d745c609 100644
--- a/src/backend/utils/sort/tuplestore.c
+++ b/src/backend/utils/sort/tuplestore.c
@@ -107,9 +107,10 @@ struct Tuplestorestate
 	bool		backward;		/* store extra length words in file? */
 	bool		interXact;		/* keep open through transactions? */
 	bool		truncated;		/* tuplestore_trim has removed tuples? */
+	bool		usedDisk;		/* true if tuple store has ever gone to disk */
 	int64		availMem;		/* remaining memory available, in bytes */
 	int64		allowedMem;		/* total memory allowed, in bytes */
-	int64		maxSpace;		/* maximum space used in memory */
+	int64		maxSpace;		/* maximum space used in memory or disk */
 	int64		tuples;			/* number of tuples added */
 	BufFile    *myfile;			/* underlying file, or NULL if none */
 	MemoryContext context;		/* memory context for holding tuples */
@@ -262,6 +263,7 @@ tuplestore_begin_common(int eflags, bool interXact, int maxKBytes)
 	state->eflags = eflags;
 	state->interXact = interXact;
 	state->truncated = false;
+	state->usedDisk = false;
 	state->allowedMem = maxKBytes * 1024L;
 	state->availMem = state->allowedMem;
 	state->maxSpace = 0;
@@ -1499,17 +1501,25 @@ tuplestore_updatemax(Tuplestorestate *state)
 	if (state->status == TSS_INMEM)
 		state->maxSpace = Max(state->maxSpace,
 							  state->allowedMem - state->availMem);
+	else
+	{
+		state->maxSpace = Max(state->maxSpace,
+							  BufFileSize(state->myfile));
+		state->usedDisk = true;
+	}
 }
 
 /*
  * tuplestore_storage_type_name
  *		Return a string description of the storage method used to store the
- *		tuples.
+ *		tuples.  We don't use the current status as if the tuplestore went to
+ *		disk and a tuplestore_clear() allowed it to switch back to memory
+ *		again, we still want to know that it has spilled to disk.
  */
 const char *
 tuplestore_storage_type_name(Tuplestorestate *state)
 {
-	if (state->status == TSS_INMEM)
+	if (!state->usedDisk)
 		return "Memory";
 	else
 		return "Disk";
@@ -1517,8 +1527,7 @@ tuplestore_storage_type_name(Tuplestorestate *state)
 
 /*
  * tuplestore_space_used
- *		Return the maximum space used in memory unless the tuplestore has spilled
- *		to disk, in which case, return the disk space used.
+ *		Return the maximum space used in memory or disk.
  */
 int64
 tuplestore_space_used(Tuplestorestate *state)
@@ -1526,10 +1535,7 @@ tuplestore_space_used(Tuplestorestate *state)
 	/* First, update the maxSpace field */
 	tuplestore_updatemax(state);
 
-	if (state->status == TSS_INMEM)
-		return state->maxSpace;
-	else
-		return BufFileSize(state->myfile);
+	return state->maxSpace;
 }
 
 /*
@@ -1601,7 +1607,6 @@ writetup_heap(Tuplestorestate *state, void *tup)
 	if (state->backward)		/* need trailing length word? */
 		BufFileWrite(state->myfile, &tuplen, sizeof(tuplen));
 
-	/* no need to call tuplestore_updatemax() when not in TSS_INMEM */
 	FREEMEM(state, GetMemoryChunkSpace(tuple));
 	heap_free_minimal_tuple(tuple);
 }