2 files changed, 90 insertions, 0 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 30de9de9d4f..1b5ab503898 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -125,6 +125,7 @@ static void show_sort_info(SortState *sortstate, ExplainState *es);
 static void show_incremental_sort_info(IncrementalSortState *incrsortstate,
 									   ExplainState *es);
 static void show_hash_info(HashState *hashstate, ExplainState *es);
+static void show_material_info(MaterialState *mstate, ExplainState *es);
 static void show_memoize_info(MemoizeState *mstate, List *ancestors,
 							  ExplainState *es);
 static void show_hashagg_info(AggState *aggstate, ExplainState *es);
@@ -2251,6 +2252,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		case T_Hash:
 			show_hash_info(castNode(HashState, planstate), es);
 			break;
+		case T_Material:
+			show_material_info(castNode(MaterialState, planstate), es);
+			break;
 		case T_Memoize:
 			show_memoize_info(castNode(MemoizeState, planstate), ancestors,
 							  es);
@@ -3323,6 +3327,39 @@ show_hash_info(HashState *hashstate, ExplainState *es)
 }
 
 /*
+ * Show information on material node, storage method and maximum memory/disk
+ * space used.
+ */
+static void
+show_material_info(MaterialState *mstate, ExplainState *es)
+{
+	Tuplestorestate *tupstore;
+	const char *storageType;
+	int64		spaceUsedKB;
+
+	if (!es->analyze)
+		return;
+
+	tupstore = mstate->tuplestorestate;
+	storageType = tuplestore_storage_type_name(tupstore);
+	spaceUsedKB = BYTES_TO_KILOBYTES(tuplestore_space_used(tupstore));
+
+	if (es->format != EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainPropertyText("Storage", storageType, es);
+		ExplainPropertyInteger("Maximum Storage", "kB", spaceUsedKB, es);
+	}
+	else
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str,
+						 "Storage: %s  Maximum Storage: " INT64_FORMAT "kB\n",
+						 storageType,
+						 spaceUsedKB);
+	}
+}
+
+/*
  * Show information on memoize hits/misses/evictions and memory usage.
  */
 static void
diff --git a/src/backend/utils/sort/tuplestore.c b/src/backend/utils/sort/tuplestore.c
index 947a868e569..24bb49ca874 100644
--- a/src/backend/utils/sort/tuplestore.c
+++ b/src/backend/utils/sort/tuplestore.c
@@ -109,6 +109,7 @@ struct Tuplestorestate
 	bool		truncated;		/* tuplestore_trim has removed tuples? */
 	int64		availMem;		/* remaining memory available, in bytes */
 	int64		allowedMem;		/* total memory allowed, in bytes */
+	int64		maxSpace;		/* maximum space used in memory */
 	int64		tuples;			/* number of tuples added */
 	BufFile    *myfile;			/* underlying file, or NULL if none */
 	MemoryContext context;		/* memory context for holding tuples */
@@ -238,6 +239,7 @@ static Tuplestorestate *tuplestore_begin_common(int eflags,
 												int maxKBytes);
 static void tuplestore_puttuple_common(Tuplestorestate *state, void *tuple);
 static void dumptuples(Tuplestorestate *state);
+static void tuplestore_updatemax(Tuplestorestate *state);
 static unsigned int getlen(Tuplestorestate *state, bool eofOK);
 static void *copytup_heap(Tuplestorestate *state, void *tup);
 static void writetup_heap(Tuplestorestate *state, void *tup);
@@ -262,6 +264,7 @@ tuplestore_begin_common(int eflags, bool interXact, int maxKBytes)
 	state->truncated = false;
 	state->allowedMem = maxKBytes * 1024L;
 	state->availMem = state->allowedMem;
+	state->maxSpace = 0;
 	state->myfile = NULL;
 	state->context = CurrentMemoryContext;
 	state->resowner = CurrentResourceOwner;
@@ -420,6 +423,9 @@ tuplestore_clear(Tuplestorestate *state)
 	int			i;
 	TSReadPointer *readptr;
 
+	/* update the maxSpace before doing any USEMEM/FREEMEM adjustments */
+	tuplestore_updatemax(state);
+
 	if (state->myfile)
 		BufFileClose(state->myfile);
 	state->myfile = NULL;
@@ -1402,6 +1408,9 @@ tuplestore_trim(Tuplestorestate *state)
 	Assert(nremove >= state->memtupdeleted);
 	Assert(nremove <= state->memtupcount);
 
+	/* before freeing any memory, update maxSpace */
+	tuplestore_updatemax(state);
+
 	/* Release no-longer-needed tuples */
 	for (i = state->memtupdeleted; i < nremove; i++)
 	{
@@ -1445,6 +1454,49 @@ tuplestore_trim(Tuplestorestate *state)
 }
 
 /*
+ * tuplestore_updatemax
+ *		Update maxSpace field
+ */
+static void
+tuplestore_updatemax(Tuplestorestate *state)
+{
+	if (state->status == TSS_INMEM)
+		state->maxSpace = Max(state->maxSpace,
+							  state->allowedMem - state->availMem);
+}
+
+/*
+ * tuplestore_storage_type_name
+ *		Return a string description of the storage method used to store the
+ *		tuples.
+ */
+const char *
+tuplestore_storage_type_name(Tuplestorestate *state)
+{
+	if (state->status == TSS_INMEM)
+		return "Memory";
+	else
+		return "Disk";
+}
+
+/*
+ * 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.
+ */
+int64
+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);
+}
+
+/*
  * tuplestore_in_memory
  *
  * Returns true if the tuplestore has not spilled to disk.
@@ -1513,6 +1565,7 @@ 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);
 }