Add memory/disk usage for Window aggregate nodes in EXPLAIN.

This commit is similar to 1eff8279d and expands the idea to Window
aggregate nodes so that users can know how much memory or disk the
tuplestore used.

This commit uses newly introduced tuplestore_get_stats() to inquire this
information and add some additional output in EXPLAIN ANALYZE to
display the information for the Window aggregate node.

Reviewed-by: David Rowley, Ashutosh Bapat, Maxim Orlov, Jian He
Discussion: https://postgr.es/m/20240706.202254.89740021795421286.ishii%40postgresql.org

1 files changed, 50 insertions, 18 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 2819e479f82..aaec439892c 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -120,6 +120,7 @@ static void show_sort_group_keys(PlanState *planstate, const char *qlabel,
 								 List *ancestors, ExplainState *es);
 static void show_sortorder_options(StringInfo buf, Node *sortexpr,
 								   Oid sortOperator, Oid collation, bool nullsFirst);
+static void show_storage_info(Tuplestorestate *tupstore, ExplainState *es);
 static void show_tablesample(TableSampleClause *tsc, PlanState *planstate,
 							 List *ancestors, ExplainState *es);
 static void show_sort_info(SortState *sortstate, ExplainState *es);
@@ -127,6 +128,7 @@ 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_windowagg_info(WindowAggState *winstate, ExplainState *es);
 static void show_memoize_info(MemoizeState *mstate, List *ancestors,
 							  ExplainState *es);
 static void show_hashagg_info(AggState *aggstate, ExplainState *es);
@@ -2231,6 +2233,7 @@ ExplainNode(PlanState *planstate, List *ancestors,
 										   planstate, es);
 			show_upper_qual(((WindowAgg *) plan)->runConditionOrig,
 							"Run Condition", planstate, ancestors, es);
+			show_windowagg_info(castNode(WindowAggState, planstate), es);
 			break;
 		case T_Group:
 			show_group_keys(castNode(GroupState, planstate), ancestors, es);
@@ -2895,6 +2898,34 @@ show_sortorder_options(StringInfo buf, Node *sortexpr,
 }
 
 /*
+ * Show information on storage method and maximum memory/disk space used.
+ */
+static void
+show_storage_info(Tuplestorestate *tupstore, ExplainState *es)
+{
+	char	   *maxStorageType;
+	int64		maxSpaceUsed,
+				maxSpaceUsedKB;
+
+	tuplestore_get_stats(tupstore, &maxStorageType, &maxSpaceUsed);
+	maxSpaceUsedKB = BYTES_TO_KILOBYTES(maxSpaceUsed);
+
+	if (es->format != EXPLAIN_FORMAT_TEXT)
+	{
+		ExplainPropertyText("Storage", maxStorageType, es);
+		ExplainPropertyInteger("Maximum Storage", "kB", maxSpaceUsedKB, es);
+	}
+	else
+	{
+		ExplainIndentText(es);
+		appendStringInfo(es->str,
+						 "Storage: %s  Maximum Storage: " INT64_FORMAT "kB\n",
+						 maxStorageType,
+						 maxSpaceUsedKB);
+	}
+}
+
+/*
  * Show TABLESAMPLE properties
  */
 static void
@@ -3350,9 +3381,6 @@ static void
 show_material_info(MaterialState *mstate, ExplainState *es)
 {
 	Tuplestorestate *tupstore = mstate->tuplestorestate;
-	char	   *maxStorageType;
-	int64		maxSpaceUsed,
-				maxSpaceUsedKB;
 
 	/*
 	 * Nothing to show if ANALYZE option wasn't used or if execution didn't
@@ -3361,22 +3389,26 @@ show_material_info(MaterialState *mstate, ExplainState *es)
 	if (!es->analyze || tupstore == NULL)
 		return;
 
-	tuplestore_get_stats(tupstore, &maxStorageType, &maxSpaceUsed);
-	maxSpaceUsedKB = BYTES_TO_KILOBYTES(maxSpaceUsed);
+	show_storage_info(tupstore, es);
+}
 
-	if (es->format != EXPLAIN_FORMAT_TEXT)
-	{
-		ExplainPropertyText("Storage", maxStorageType, es);
-		ExplainPropertyInteger("Maximum Storage", "kB", maxSpaceUsedKB, es);
-	}
-	else
-	{
-		ExplainIndentText(es);
-		appendStringInfo(es->str,
-						 "Storage: %s  Maximum Storage: " INT64_FORMAT "kB\n",
-						 maxStorageType,
-						 maxSpaceUsedKB);
-	}
+/*
+ * Show information on WindowAgg node, storage method and maximum memory/disk
+ * space used.
+ */
+static void
+show_windowagg_info(WindowAggState *winstate, ExplainState *es)
+{
+	Tuplestorestate *tupstore = winstate->buffer;
+
+	/*
+	 * Nothing to show if ANALYZE option wasn't used or if execution didn't
+	 * get as far as creating the tuplestore.
+	 */
+	if (!es->analyze || tupstore == NULL)
+		return;
+
+	show_storage_info(tupstore, es);
 }
 
 /*