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

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 2819e479f82a93e7a3cc01d35c86f3bdab5cc1a1..aaec439892c75835ca8fd968b3abbf0b7773be38 100644 (file)
--- 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);
@@ -2894,6 +2897,34 @@ 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
  */
@@ -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);
 }
 
 /*

diff --git a/src/test/regress/expected/explain.out b/src/test/regress/expected/explain.out
index 6585c6a69efe45d4eefd674425762df69dfd9bef..d01c304c24d1f6dd57deb8274d5266660aaae19d 100644 (file)
--- a/src/test/regress/expected/explain.out
+++ b/src/test/regress/expected/explain.out
@@ -691,3 +691,41 @@ select explain_filter('explain (analyze,serialize) create temp table explain_tem
  Execution Time: N.N ms
 (4 rows)
 
+-- Test tuplestore storage usage in Window aggregate (memory case)
+select explain_filter('explain (analyze,costs off) select sum(n) over() from generate_series(1,10) a(n)');
+                                 explain_filter                                 
+--------------------------------------------------------------------------------
+ WindowAgg (actual time=N.N..N.N rows=N loops=N)
+   Storage: Memory  Maximum Storage: NkB
+   ->  Function Scan on generate_series a (actual time=N.N..N.N rows=N loops=N)
+ Planning Time: N.N ms
+ Execution Time: N.N ms
+(5 rows)
+
+-- Test tuplestore storage usage in Window aggregate (disk case)
+set work_mem to 64;
+select explain_filter('explain (analyze,costs off) select sum(n) over() from generate_series(1,2000) a(n)');
+                                 explain_filter                                 
+--------------------------------------------------------------------------------
+ WindowAgg (actual time=N.N..N.N rows=N loops=N)
+   Storage: Disk  Maximum Storage: NkB
+   ->  Function Scan on generate_series a (actual time=N.N..N.N rows=N loops=N)
+ Planning Time: N.N ms
+ Execution Time: N.N ms
+(5 rows)
+
+-- Test tuplestore storage usage in Window aggregate (memory and disk case, final result is disk)
+select explain_filter('explain (analyze,costs off) select sum(n) over(partition by m) from (SELECT n < 3 as m, n from generate_series(1,2000) a(n))');
+                                    explain_filter                                    
+--------------------------------------------------------------------------------------
+ WindowAgg (actual time=N.N..N.N rows=N loops=N)
+   Storage: Disk  Maximum Storage: NkB
+   ->  Sort (actual time=N.N..N.N rows=N loops=N)
+         Sort Key: ((a.n < N))
+         Sort Method: external merge  Disk: NkB
+         ->  Function Scan on generate_series a (actual time=N.N..N.N rows=N loops=N)
+ Planning Time: N.N ms
+ Execution Time: N.N ms
+(8 rows)
+
+reset work_mem;

diff --git a/src/test/regress/sql/explain.sql b/src/test/regress/sql/explain.sql
index c7055f850c557b9d264e3b4e788845b24fa882d0..b861e2b53d57354f0caf527d649dbe5199cf577c 100644 (file)
--- a/src/test/regress/sql/explain.sql
+++ b/src/test/regress/sql/explain.sql
@@ -169,3 +169,12 @@ select explain_filter('explain (analyze,serialize text,buffers,timing off) selec
 select explain_filter('explain (analyze,serialize binary,buffers,timing) select * from int8_tbl i8');
 -- this tests an edge case where we have no data to return
 select explain_filter('explain (analyze,serialize) create temp table explain_temp as select * from int8_tbl i8');
+
+-- Test tuplestore storage usage in Window aggregate (memory case)
+select explain_filter('explain (analyze,costs off) select sum(n) over() from generate_series(1,10) a(n)');
+-- Test tuplestore storage usage in Window aggregate (disk case)
+set work_mem to 64;
+select explain_filter('explain (analyze,costs off) select sum(n) over() from generate_series(1,2000) a(n)');
+-- Test tuplestore storage usage in Window aggregate (memory and disk case, final result is disk)
+select explain_filter('explain (analyze,costs off) select sum(n) over(partition by m) from (SELECT n < 3 as m, n from generate_series(1,2000) a(n))');
+reset work_mem;