Add parallel columns for pg_stat_statements

From 8228f8d521eb9853cba6b5d185e4d9965f29d398 Mon Sep 17 00:00:00 2001
From: Guillaume Lelarge <guillaume.lelarge@dalibo.com>
Date: Wed, 28 Aug 2024 15:30:05 +0200
Subject: [PATCH v2] Add parallel columns to pg_stat_statements

There are seven new columns:
 * parallelized_queries_planned (number of times the query has been planned to
   be parallelized),
 * parallel_ized_querieslaunched (number of times the query has been executed
   with parallelization),
 * parallelized_workers_planned (number of parallel workers planned for
   this query),
 * parallelized_workers_launched (number of parallel workers executed for
   this query),
 * parallelized_nodes (number of parallelized nodes),
 * parallelized_nodes_all_workers (number of parallelized nodes which
   had all requested workers),
 * parallelized_nodes_no_worker (number of parallelized nodes which had
   no requested workers).

These new columns will help to monitor and better configure query
parallelization.
---
 contrib/pg_stat_statements/Makefile           |   4 +-
 .../expected/oldextversions.out               |  69 +++++++++++
 .../pg_stat_statements/expected/parallel.out  |  38 ++++++
 .../pg_stat_statements--1.11--1.12.sql        |  80 +++++++++++++
 .../pg_stat_statements/pg_stat_statements.c   | 108 ++++++++++++++++--
 .../pg_stat_statements.control                |   2 +-
 .../pg_stat_statements/sql/oldextversions.sql |   5 +
 contrib/pg_stat_statements/sql/parallel.sql   |  27 +++++
 doc/src/sgml/pgstatstatements.sgml            |  63 ++++++++++
 src/backend/executor/execUtils.c              |   7 ++
 src/backend/executor/nodeGather.c             |   9 +-
 src/backend/executor/nodeGatherMerge.c        |   8 ++
 src/include/nodes/execnodes.h                 |   6 +
 13 files changed, 415 insertions(+), 11 deletions(-)
 create mode 100644 contrib/pg_stat_statements/expected/parallel.out
 create mode 100644 contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
 create mode 100644 contrib/pg_stat_statements/sql/parallel.sql

diff --git a/contrib/pg_stat_statements/Makefile b/contrib/pg_stat_statements/Makefile
index 1622b43ded..0caeea0c03 100644
--- a/contrib/pg_stat_statements/Makefile
+++ b/contrib/pg_stat_statements/Makefile
@@ -7,7 +7,7 @@ OBJS = \
 
 EXTENSION = pg_stat_statements
 DATA = pg_stat_statements--1.4.sql \
-	pg_stat_statements--1.10--1.11.sql \
+	pg_stat_statements--1.11--1.12.sql pg_stat_statements--1.10--1.11.sql \
 	pg_stat_statements--1.9--1.10.sql pg_stat_statements--1.8--1.9.sql \
 	pg_stat_statements--1.7--1.8.sql pg_stat_statements--1.6--1.7.sql \
 	pg_stat_statements--1.5--1.6.sql pg_stat_statements--1.4--1.5.sql \
@@ -19,7 +19,7 @@ LDFLAGS_SL += $(filter -lm, $(LIBS))
 
 REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/pg_stat_statements/pg_stat_statements.conf
 REGRESS = select dml cursors utility level_tracking planning \
-	user_activity wal entry_timestamp privileges extended cleanup \
+	user_activity wal entry_timestamp privileges extended parallel cleanup \
 	oldextversions
 # Disabled because these tests require "shared_preload_libraries=pg_stat_statements",
 # which typical installcheck users do not have (e.g. buildfarm clients).
diff --git a/contrib/pg_stat_statements/expected/oldextversions.out b/contrib/pg_stat_statements/expected/oldextversions.out
index 5842c930e5..a4e8dc0bde 100644
--- a/contrib/pg_stat_statements/expected/oldextversions.out
+++ b/contrib/pg_stat_statements/expected/oldextversions.out
@@ -342,4 +342,73 @@ SELECT pg_stat_statements_reset() IS NOT NULL AS t;
  t
 (1 row)
 
+-- New functions and views for pg_stat_statements in 1.12
+AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
+\d pg_stat_statements
+                              View "public.pg_stat_statements"
+             Column             |           Type           | Collation | Nullable | Default 
+--------------------------------+--------------------------+-----------+----------+---------
+ userid                         | oid                      |           |          | 
+ dbid                           | oid                      |           |          | 
+ toplevel                       | boolean                  |           |          | 
+ queryid                        | bigint                   |           |          | 
+ query                          | text                     |           |          | 
+ plans                          | bigint                   |           |          | 
+ total_plan_time                | double precision         |           |          | 
+ min_plan_time                  | double precision         |           |          | 
+ max_plan_time                  | double precision         |           |          | 
+ mean_plan_time                 | double precision         |           |          | 
+ stddev_plan_time               | double precision         |           |          | 
+ calls                          | bigint                   |           |          | 
+ total_exec_time                | double precision         |           |          | 
+ min_exec_time                  | double precision         |           |          | 
+ max_exec_time                  | double precision         |           |          | 
+ mean_exec_time                 | double precision         |           |          | 
+ stddev_exec_time               | double precision         |           |          | 
+ rows                           | bigint                   |           |          | 
+ shared_blks_hit                | bigint                   |           |          | 
+ shared_blks_read               | bigint                   |           |          | 
+ shared_blks_dirtied            | bigint                   |           |          | 
+ shared_blks_written            | bigint                   |           |          | 
+ local_blks_hit                 | bigint                   |           |          | 
+ local_blks_read                | bigint                   |           |          | 
+ local_blks_dirtied             | bigint                   |           |          | 
+ local_blks_written             | bigint                   |           |          | 
+ temp_blks_read                 | bigint                   |           |          | 
+ temp_blks_written              | bigint                   |           |          | 
+ shared_blk_read_time           | double precision         |           |          | 
+ shared_blk_write_time          | double precision         |           |          | 
+ local_blk_read_time            | double precision         |           |          | 
+ local_blk_write_time           | double precision         |           |          | 
+ temp_blk_read_time             | double precision         |           |          | 
+ temp_blk_write_time            | double precision         |           |          | 
+ wal_records                    | bigint                   |           |          | 
+ wal_fpi                        | bigint                   |           |          | 
+ wal_bytes                      | numeric                  |           |          | 
+ jit_functions                  | bigint                   |           |          | 
+ jit_generation_time            | double precision         |           |          | 
+ jit_inlining_count             | bigint                   |           |          | 
+ jit_inlining_time              | double precision         |           |          | 
+ jit_optimization_count         | bigint                   |           |          | 
+ jit_optimization_time          | double precision         |           |          | 
+ jit_emission_count             | bigint                   |           |          | 
+ jit_emission_time              | double precision         |           |          | 
+ jit_deform_count               | bigint                   |           |          | 
+ jit_deform_time                | double precision         |           |          | 
+ parallelized_queries_planned   | bigint                   |           |          | 
+ parallelized_queries_launched  | bigint                   |           |          | 
+ parallelized_workers_planned   | bigint                   |           |          | 
+ parallelized_workers_launched  | bigint                   |           |          | 
+ parallelized_nodes             | bigint                   |           |          | 
+ parallelized_nodes_all_workers | bigint                   |           |          | 
+ parallelized_nodes_no_worker   | bigint                   |           |          | 
+ stats_since                    | timestamp with time zone |           |          | 
+ minmax_stats_since             | timestamp with time zone |           |          | 
+
+SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
+ has_data 
+----------
+ t
+(1 row)
+
 DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/expected/parallel.out b/contrib/pg_stat_statements/expected/parallel.out
new file mode 100644
index 0000000000..1379d10e97
--- /dev/null
+++ b/contrib/pg_stat_statements/expected/parallel.out
@@ -0,0 +1,38 @@
+--
+-- Validate parallelization generation metrics
+--
+SET parallel_setup_cost TO 0;
+SET min_parallel_table_scan_size TO '100kB';
+SET pg_stat_statements.track_utility = FALSE;
+CREATE TABLE pgss_parallel_tab (a int);
+INSERT INTO pgss_parallel_tab SELECT generate_series(1, 10_000);
+SELECT count(*) FROM pgss_parallel_tab;
+ count 
+-------
+ 10000
+(1 row)
+
+DROP TABLE pgss_parallel_tab;
+-- Check parallelization metrics are generated for the SELECT statement
+SELECT query,
+  parallelized_queries_planned > 0 AS parallelized_queries_planned_generated,
+  parallelized_queries_launched > 0 AS parallelized_queries_launched_generated,
+  parallelized_workers_planned > 0 AS parallelized_workers_planned_generated,
+  parallelized_workers_launched > 0 AS parallelized_workers_launched_generated,
+  parallelized_nodes > 0 AS parallelized_nodes_generated,
+  parallelized_nodes_all_workers > 0 AS parallelized_nodes_all_workers_generated,
+  parallelized_nodes_no_worker = 0 AS parallelized_nodes_no_worker_generated 
+FROM pg_stat_statements
+WHERE query LIKE 'SELECT count%'
+ORDER BY query COLLATE "C";
+                 query                  | parallelized_queries_planned_generated | parallelized_queries_launched_generated | parallelized_workers_planned_generated | parallelized_workers_launched_generated | parallelized_nodes_generated | parallelized_nodes_all_workers_generated | parallelized_nodes_no_worker_generated 
+----------------------------------------+----------------------------------------+-----------------------------------------+----------------------------------------+-----------------------------------------+------------------------------+------------------------------------------+----------------------------------------
+ SELECT count(*) FROM pgss_parallel_tab | t                                      | t                                       | t                                      | t                                       | t                            | t                                        | t
+(1 row)
+
+SELECT pg_stat_statements_reset() IS NOT NULL AS t;
+ t 
+---
+ t
+(1 row)
+
diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
new file mode 100644
index 0000000000..6f4fe8be48
--- /dev/null
+++ b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
@@ -0,0 +1,80 @@
+/* contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_stat_statements UPDATE TO '1.12'" to load this file. \quit
+
+/* First we have to remove them from the extension */
+ALTER EXTENSION pg_stat_statements DROP VIEW pg_stat_statements;
+ALTER EXTENSION pg_stat_statements DROP FUNCTION pg_stat_statements(boolean);
+
+/* Then we can drop them */
+DROP VIEW pg_stat_statements;
+DROP FUNCTION pg_stat_statements(boolean);
+
+/* Now redefine */
+CREATE FUNCTION pg_stat_statements(IN showtext boolean,
+    OUT userid oid,
+    OUT dbid oid,
+    OUT toplevel bool,
+    OUT queryid bigint,
+    OUT query text,
+    OUT plans int8,
+    OUT total_plan_time float8,
+    OUT min_plan_time float8,
+    OUT max_plan_time float8,
+    OUT mean_plan_time float8,
+    OUT stddev_plan_time float8,
+    OUT calls int8,
+    OUT total_exec_time float8,
+    OUT min_exec_time float8,
+    OUT max_exec_time float8,
+    OUT mean_exec_time float8,
+    OUT stddev_exec_time float8,
+    OUT rows int8,
+    OUT shared_blks_hit int8,
+    OUT shared_blks_read int8,
+    OUT shared_blks_dirtied int8,
+    OUT shared_blks_written int8,
+    OUT local_blks_hit int8,
+    OUT local_blks_read int8,
+    OUT local_blks_dirtied int8,
+    OUT local_blks_written int8,
+    OUT temp_blks_read int8,
+    OUT temp_blks_written int8,
+    OUT shared_blk_read_time float8,
+    OUT shared_blk_write_time float8,
+    OUT local_blk_read_time float8,
+    OUT local_blk_write_time float8,
+    OUT temp_blk_read_time float8,
+    OUT temp_blk_write_time float8,
+    OUT wal_records int8,
+    OUT wal_fpi int8,
+    OUT wal_bytes numeric,
+    OUT jit_functions int8,
+    OUT jit_generation_time float8,
+    OUT jit_inlining_count int8,
+    OUT jit_inlining_time float8,
+    OUT jit_optimization_count int8,
+    OUT jit_optimization_time float8,
+    OUT jit_emission_count int8,
+    OUT jit_emission_time float8,
+    OUT jit_deform_count int8,
+    OUT jit_deform_time float8,
+    OUT parallelized_queries_planned int8,
+    OUT parallelized_queries_launched int8,
+    OUT parallelized_workers_planned int8,
+    OUT parallelized_workers_launched int8,
+    OUT parallelized_nodes int8,
+    OUT parallelized_nodes_all_workers int8,
+    OUT parallelized_nodes_no_worker int8,
+    OUT stats_since timestamp with time zone,
+    OUT minmax_stats_since timestamp with time zone
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_stat_statements_1_12'
+LANGUAGE C STRICT VOLATILE PARALLEL SAFE;
+
+CREATE VIEW pg_stat_statements AS
+  SELECT * FROM pg_stat_statements(true);
+
+GRANT SELECT ON pg_stat_statements TO PUBLIC;
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 5765ef49b4..da94d64011 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -113,6 +113,7 @@ typedef enum pgssVersion
 	PGSS_V1_9,
 	PGSS_V1_10,
 	PGSS_V1_11,
+	PGSS_V1_12,
 } pgssVersion;
 
 typedef enum pgssStoreKind
@@ -204,6 +205,13 @@ typedef struct Counters
 	int64		jit_emission_count; /* number of times emission time has been
 									 * > 0 */
 	double		jit_emission_time;	/* total time to emit jit code */
+	int64       parallelized_queries_planned;	/* # of times query was planned to use parallelism */
+	int64       parallelized_queries_launched;	/* # of times query was executed using parallelism */
+	int64       parallelized_workers_planned;	/* # of parallel workers planned */
+	int64       parallelized_workers_launched;	/* # of parallel workers launched */
+	int64       parallelized_nodes;				/* # of parallelized nodes */
+	int64       parallelized_nodes_all_workers;	/* # of parallelized nodes with all workers */
+	int64       parallelized_nodes_no_worker;	/* # of parallelized nodes with no workers */
 } Counters;
 
 /*
@@ -317,6 +325,7 @@ PG_FUNCTION_INFO_V1(pg_stat_statements_1_8);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_9);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_10);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_11);
+PG_FUNCTION_INFO_V1(pg_stat_statements_1_12);
 PG_FUNCTION_INFO_V1(pg_stat_statements);
 PG_FUNCTION_INFO_V1(pg_stat_statements_info);
 
@@ -347,7 +356,14 @@ static void pgss_store(const char *query, uint64 queryId,
 					   const BufferUsage *bufusage,
 					   const WalUsage *walusage,
 					   const struct JitInstrumentation *jitusage,
-					   JumbleState *jstate);
+					   JumbleState *jstate,
+					   bool parallelized_queries_planned,
+					   bool parallelized_queries_launched,
+					   int parallelized_workers_planned,
+					   int parallelized_workers_launched,
+					   int parallelized_nodes,
+					   int parallelized_nodes_all_workers,
+					   int parallelized_nodes_no_worker);
 static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
 										pgssVersion api_version,
 										bool showtext);
@@ -867,7 +883,14 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 				   NULL,
 				   NULL,
 				   NULL,
-				   jstate);
+				   jstate,
+				   false,
+				   false,
+				   0,
+				   0,
+				   0,
+				   0,
+				   0);
 }
 
 /*
@@ -945,7 +968,14 @@ pgss_planner(Query *parse,
 				   &bufusage,
 				   &walusage,
 				   NULL,
-				   NULL);
+				   NULL,
+				   false,
+				   false,
+				   0,
+				   0,
+				   0,
+				   0,
+				   0);
 	}
 	else
 	{
@@ -1078,7 +1108,14 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
 				   &queryDesc->totaltime->bufusage,
 				   &queryDesc->totaltime->walusage,
 				   queryDesc->estate->es_jit ? &queryDesc->estate->es_jit->instr : NULL,
-				   NULL);
+				   NULL,
+				   queryDesc->plannedstmt->parallelModeNeeded,
+				   queryDesc->estate->es_used_parallel_mode,
+				   queryDesc->estate->es_parallelized_workers_planned,
+				   queryDesc->estate->es_parallelized_workers_launched,
+				   queryDesc->estate->es_parallelized_nodes,
+				   queryDesc->estate->es_parallelized_nodes_all_workers,
+				   queryDesc->estate->es_parallelized_nodes_no_worker);
 	}
 
 	if (prev_ExecutorEnd)
@@ -1209,7 +1246,14 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 				   &bufusage,
 				   &walusage,
 				   NULL,
-				   NULL);
+				   NULL,
+				   false,
+				   false,
+				   0,
+				   0,
+				   0,
+				   0,
+				   0);
 	}
 	else
 	{
@@ -1270,7 +1314,14 @@ pgss_store(const char *query, uint64 queryId,
 		   const BufferUsage *bufusage,
 		   const WalUsage *walusage,
 		   const struct JitInstrumentation *jitusage,
-		   JumbleState *jstate)
+		   JumbleState *jstate,
+		   bool parallelized_queries_planned,
+		   bool parallelized_queries_launched,
+		   int parallelized_workers_planned,
+		   int parallelized_workers_launched,
+		   int parallelized_nodes,
+		   int parallelized_nodes_all_workers,
+		   int parallelized_nodes_no_worker)
 {
 	pgssHashKey key;
 	pgssEntry  *entry;
@@ -1472,6 +1523,20 @@ pgss_store(const char *query, uint64 queryId,
 				entry->counters.jit_emission_count++;
 			entry->counters.jit_emission_time += INSTR_TIME_GET_MILLISEC(jitusage->emission_counter);
 		}
+		/* inc parallel counters */
+		if (parallelized_queries_planned)
+		{
+			entry->counters.parallelized_queries_planned += 1;
+		}
+		if (parallelized_queries_launched)
+		{
+			entry->counters.parallelized_queries_launched += 1;
+		}
+		entry->counters.parallelized_workers_planned += parallelized_workers_planned;
+		entry->counters.parallelized_workers_launched += parallelized_workers_launched;
+		entry->counters.parallelized_nodes += parallelized_nodes;
+		entry->counters.parallelized_nodes_all_workers += parallelized_nodes_all_workers;
+		entry->counters.parallelized_nodes_no_worker += parallelized_nodes_no_worker;
 
 		SpinLockRelease(&entry->mutex);
 	}
@@ -1539,7 +1604,8 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
 #define PG_STAT_STATEMENTS_COLS_V1_9	33
 #define PG_STAT_STATEMENTS_COLS_V1_10	43
 #define PG_STAT_STATEMENTS_COLS_V1_11	49
-#define PG_STAT_STATEMENTS_COLS			49	/* maximum of above */
+#define PG_STAT_STATEMENTS_COLS_V1_12	56
+#define PG_STAT_STATEMENTS_COLS			56	/* maximum of above */
 
 /*
  * Retrieve statement statistics.
@@ -1551,6 +1617,16 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
  * expected API version is identified by embedding it in the C name of the
  * function.  Unfortunately we weren't bright enough to do that for 1.1.
  */
+Datum
+pg_stat_statements_1_12(PG_FUNCTION_ARGS)
+{
+	bool		showtext = PG_GETARG_BOOL(0);
+
+	pg_stat_statements_internal(fcinfo, PGSS_V1_12, showtext);
+
+	return (Datum) 0;
+}
+
 Datum
 pg_stat_statements_1_11(PG_FUNCTION_ARGS)
 {
@@ -1695,6 +1771,10 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 			if (api_version != PGSS_V1_11)
 				elog(ERROR, "incorrect number of output arguments");
 			break;
+		case PG_STAT_STATEMENTS_COLS_V1_12:
+			if (api_version != PGSS_V1_12)
+				elog(ERROR, "incorrect number of output arguments");
+			break;
 		default:
 			elog(ERROR, "incorrect number of output arguments");
 	}
@@ -1932,6 +2012,19 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 		{
 			values[i++] = Int64GetDatumFast(tmp.jit_deform_count);
 			values[i++] = Float8GetDatumFast(tmp.jit_deform_time);
+		}
+		if (api_version >= PGSS_V1_12)
+		{
+			values[i++] = Int64GetDatumFast(tmp.parallelized_queries_planned);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_queries_launched);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_workers_planned);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_workers_launched);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_nodes);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_nodes_all_workers);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_nodes_no_worker);
+		}
+		if (api_version >= PGSS_V1_11)
+		{
 			values[i++] = TimestampTzGetDatum(stats_since);
 			values[i++] = TimestampTzGetDatum(minmax_stats_since);
 		}
@@ -1944,6 +2037,7 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 					 api_version == PGSS_V1_9 ? PG_STAT_STATEMENTS_COLS_V1_9 :
 					 api_version == PGSS_V1_10 ? PG_STAT_STATEMENTS_COLS_V1_10 :
 					 api_version == PGSS_V1_11 ? PG_STAT_STATEMENTS_COLS_V1_11 :
+					 api_version == PGSS_V1_12 ? PG_STAT_STATEMENTS_COLS_V1_12 :
 					 -1 /* fail if you forget to update this assert */ ));
 
 		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
diff --git a/contrib/pg_stat_statements/pg_stat_statements.control b/contrib/pg_stat_statements/pg_stat_statements.control
index 8a76106ec6..d45ebc12e3 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.control
+++ b/contrib/pg_stat_statements/pg_stat_statements.control
@@ -1,5 +1,5 @@
 # pg_stat_statements extension
 comment = 'track planning and execution statistics of all SQL statements executed'
-default_version = '1.11'
+default_version = '1.12'
 module_pathname = '$libdir/pg_stat_statements'
 relocatable = true
diff --git a/contrib/pg_stat_statements/sql/oldextversions.sql b/contrib/pg_stat_statements/sql/oldextversions.sql
index 38d5505d0d..13b8ca2858 100644
--- a/contrib/pg_stat_statements/sql/oldextversions.sql
+++ b/contrib/pg_stat_statements/sql/oldextversions.sql
@@ -58,4 +58,9 @@ SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
 SELECT pg_get_functiondef('pg_stat_statements_reset'::regproc);
 SELECT pg_stat_statements_reset() IS NOT NULL AS t;
 
+-- New functions and views for pg_stat_statements in 1.12
+AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
+\d pg_stat_statements
+SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
+
 DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/sql/parallel.sql b/contrib/pg_stat_statements/sql/parallel.sql
new file mode 100644
index 0000000000..bdc9be6e1e
--- /dev/null
+++ b/contrib/pg_stat_statements/sql/parallel.sql
@@ -0,0 +1,27 @@
+--
+-- Validate parallelization generation metrics
+--
+
+SET parallel_setup_cost TO 0;
+SET min_parallel_table_scan_size TO '100kB';
+SET pg_stat_statements.track_utility = FALSE;
+
+CREATE TABLE pgss_parallel_tab (a int);
+INSERT INTO pgss_parallel_tab SELECT generate_series(1, 10_000);
+SELECT count(*) FROM pgss_parallel_tab;
+DROP TABLE pgss_parallel_tab;
+
+-- Check parallelization metrics are generated for the SELECT statement
+SELECT query,
+  parallelized_queries_planned > 0 AS parallelized_queries_planned_generated,
+  parallelized_queries_launched > 0 AS parallelized_queries_launched_generated,
+  parallelized_workers_planned > 0 AS parallelized_workers_planned_generated,
+  parallelized_workers_launched > 0 AS parallelized_workers_launched_generated,
+  parallelized_nodes > 0 AS parallelized_nodes_generated,
+  parallelized_nodes_all_workers > 0 AS parallelized_nodes_all_workers_generated,
+  parallelized_nodes_no_worker = 0 AS parallelized_nodes_no_worker_generated 
+FROM pg_stat_statements
+WHERE query LIKE 'SELECT count%'
+ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset() IS NOT NULL AS t;
diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 9b0aff73b1..3fe84ba994 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -527,6 +527,69 @@
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_queries_planned</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of times the statement was planned to use parallelism.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_queries_launched</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of times that the statement was executed using parallelism
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_workers_planned</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallel workers planned for the query.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_workers_launched</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallel workers executed for the query.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_nodes</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallelized nodes
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_nodes_all_workers</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallelized nodes that got all workers
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_nodes_no_worker</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallelized nodes that got no worker at all
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stats_since</structfield> <type>timestamp with time zone</type>
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 5737f9f4eb..3b0715d604 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -158,10 +158,17 @@ CreateExecutorState(void)
 	estate->es_sourceText = NULL;
 
 	estate->es_use_parallel_mode = false;
+	estate->es_used_parallel_mode = false;
 
 	estate->es_jit_flags = 0;
 	estate->es_jit = NULL;
 
+	estate->es_parallelized_nodes = 0;
+	estate->es_parallelized_nodes_all_workers = 0;
+	estate->es_parallelized_nodes_no_worker = 0;
+	estate->es_parallelized_workers_launched = 0;
+	estate->es_parallelized_workers_planned = 0;
+
 	/*
 	 * Return the executor state structure
 	 */
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 5d4ffe989c..f1f772ecb6 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -181,7 +181,13 @@ ExecGather(PlanState *pstate)
 			LaunchParallelWorkers(pcxt);
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
-
+			if(pcxt->nworkers_launched > 0)
+				estate->es_used_parallel_mode = true;
+			estate->es_parallelized_nodes += 1;
+			estate->es_parallelized_workers_launched += pcxt->nworkers_launched;
+			estate->es_parallelized_workers_planned += pcxt->nworkers_to_launch;
+			if (pcxt->nworkers_to_launch == pcxt->nworkers_launched)
+				estate->es_parallelized_nodes_all_workers += 1;
 			/* Set up tuple queue readers to read the results. */
 			if (pcxt->nworkers_launched > 0)
 			{
@@ -198,6 +204,7 @@ ExecGather(PlanState *pstate)
 				/* No workers?	Then never mind. */
 				node->nreaders = 0;
 				node->reader = NULL;
+				estate->es_parallelized_nodes_no_worker += 1;
 			}
 			node->nextreader = 0;
 		}
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 45f6017c29..5678b25a86 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -222,6 +222,13 @@ ExecGatherMerge(PlanState *pstate)
 			LaunchParallelWorkers(pcxt);
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
+			if(pcxt->nworkers_launched > 0)
+				estate->es_used_parallel_mode = true;
+			estate->es_parallelized_nodes += 1;
+			estate->es_parallelized_workers_launched += pcxt->nworkers_launched;
+			estate->es_parallelized_workers_planned += pcxt->nworkers_to_launch;
+			if (pcxt->nworkers_to_launch == pcxt->nworkers_launched)
+				estate->es_parallelized_nodes_all_workers += 1;
 
 			/* Set up tuple queue readers to read the results. */
 			if (pcxt->nworkers_launched > 0)
@@ -239,6 +246,7 @@ ExecGatherMerge(PlanState *pstate)
 				/* No workers?	Then never mind. */
 				node->nreaders = 0;
 				node->reader = NULL;
+				estate->es_parallelized_nodes_no_worker += 1;
 			}
 		}
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index aab59d681c..d114e8d522 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -707,6 +707,12 @@ typedef struct EState
 	struct EPQState *es_epq_active;
 
 	bool		es_use_parallel_mode;	/* can we use parallel workers? */
+	bool		es_used_parallel_mode;	/* was executed in parallel */
+	int			es_parallelized_workers_launched;
+	int			es_parallelized_workers_planned;
+	int			es_parallelized_nodes; /* # of parallelized nodes */
+	int			es_parallelized_nodes_all_workers; /* # of nodes with all workers launched */
+	int			es_parallelized_nodes_no_worker; /* # of nodes with no workers launched */
 
 	/* The per-query shared memory area to use for parallel execution. */
 	struct dsa_area *es_query_dsa;
-- 
2.46.2

From 95b300eeff0168f2618418102df660f1ba9b9113 Mon Sep 17 00:00:00 2001
From: Guillaume Lelarge <guillaume.lelarge@dalibo.com>
Date: Mon, 7 Oct 2024 08:45:36 +0200
Subject: [PATCH v3 1/2] Introduce two new counters in EState

They will be used by two other patchs to populate new columns in
pg_stat_database and pg_statements.
---
 src/backend/executor/execUtils.c       | 3 +++
 src/backend/executor/nodeGather.c      | 3 +++
 src/backend/executor/nodeGatherMerge.c | 3 +++
 src/include/nodes/execnodes.h          | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 5737f9f4eb..1908481999 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -162,6 +162,9 @@ CreateExecutorState(void)
 	estate->es_jit_flags = 0;
 	estate->es_jit = NULL;
 
+	estate->es_parallelized_workers_launched = 0;
+	estate->es_parallelized_workers_planned = 0;
+
 	/*
 	 * Return the executor state structure
 	 */
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 5d4ffe989c..0fb915175a 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -182,6 +182,9 @@ ExecGather(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			estate->es_parallelized_workers_launched += pcxt->nworkers_launched;
+			estate->es_parallelized_workers_planned += pcxt->nworkers_to_launch;
+
 			/* Set up tuple queue readers to read the results. */
 			if (pcxt->nworkers_launched > 0)
 			{
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 45f6017c29..149ab23d90 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -223,6 +223,9 @@ ExecGatherMerge(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			estate->es_parallelized_workers_launched += pcxt->nworkers_launched;
+			estate->es_parallelized_workers_planned += pcxt->nworkers_to_launch;
+
 			/* Set up tuple queue readers to read the results. */
 			if (pcxt->nworkers_launched > 0)
 			{
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index aab59d681c..f898590ece 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -708,6 +708,9 @@ typedef struct EState
 
 	bool		es_use_parallel_mode;	/* can we use parallel workers? */
 
+	int			es_parallelized_workers_launched;
+	int			es_parallelized_workers_planned;
+
 	/* The per-query shared memory area to use for parallel execution. */
 	struct dsa_area *es_query_dsa;
 
-- 
2.46.2

From bf882530dbbc4423a24ae7f9a0bd22f674664832 Mon Sep 17 00:00:00 2001
From: Guillaume Lelarge <guillaume.lelarge@dalibo.com>
Date: Mon, 7 Oct 2024 09:47:09 +0200
Subject: [PATCH v3 2/2] Add parallel columns to pg_stat_statements

There are four new columns:
 * parallelized_queries_planned (number of times the query has been planned to
   be parallelized),
 * parallel_ized_querieslaunched (number of times the query has been executed
   with parallelization),
 * parallelized_workers_planned (number of parallel workers planned for
   this query),
 * parallelized_workers_launched (number of parallel workers executed for
   this query).

These new columns will help to monitor and better configure query
parallelization.
---
 contrib/pg_stat_statements/Makefile           |  4 +-
 .../expected/oldextversions.out               | 66 +++++++++++++++
 .../pg_stat_statements/expected/parallel.out  | 35 ++++++++
 .../pg_stat_statements--1.11--1.12.sql        | 77 ++++++++++++++++++
 .../pg_stat_statements/pg_stat_statements.c   | 81 +++++++++++++++++--
 .../pg_stat_statements.control                |  2 +-
 .../pg_stat_statements/sql/oldextversions.sql |  5 ++
 contrib/pg_stat_statements/sql/parallel.sql   | 24 ++++++
 doc/src/sgml/pgstatstatements.sgml            | 36 +++++++++
 src/backend/executor/execUtils.c              |  1 +
 src/backend/executor/nodeGather.c             |  2 +
 src/backend/executor/nodeGatherMerge.c        |  2 +
 src/include/nodes/execnodes.h                 |  1 +
 13 files changed, 326 insertions(+), 10 deletions(-)
 create mode 100644 contrib/pg_stat_statements/expected/parallel.out
 create mode 100644 contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
 create mode 100644 contrib/pg_stat_statements/sql/parallel.sql

diff --git a/contrib/pg_stat_statements/Makefile b/contrib/pg_stat_statements/Makefile
index 1622b43ded..0caeea0c03 100644
--- a/contrib/pg_stat_statements/Makefile
+++ b/contrib/pg_stat_statements/Makefile
@@ -7,7 +7,7 @@ OBJS = \
 
 EXTENSION = pg_stat_statements
 DATA = pg_stat_statements--1.4.sql \
-	pg_stat_statements--1.10--1.11.sql \
+	pg_stat_statements--1.11--1.12.sql pg_stat_statements--1.10--1.11.sql \
 	pg_stat_statements--1.9--1.10.sql pg_stat_statements--1.8--1.9.sql \
 	pg_stat_statements--1.7--1.8.sql pg_stat_statements--1.6--1.7.sql \
 	pg_stat_statements--1.5--1.6.sql pg_stat_statements--1.4--1.5.sql \
@@ -19,7 +19,7 @@ LDFLAGS_SL += $(filter -lm, $(LIBS))
 
 REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/pg_stat_statements/pg_stat_statements.conf
 REGRESS = select dml cursors utility level_tracking planning \
-	user_activity wal entry_timestamp privileges extended cleanup \
+	user_activity wal entry_timestamp privileges extended parallel cleanup \
 	oldextversions
 # Disabled because these tests require "shared_preload_libraries=pg_stat_statements",
 # which typical installcheck users do not have (e.g. buildfarm clients).
diff --git a/contrib/pg_stat_statements/expected/oldextversions.out b/contrib/pg_stat_statements/expected/oldextversions.out
index 5842c930e5..1937224f56 100644
--- a/contrib/pg_stat_statements/expected/oldextversions.out
+++ b/contrib/pg_stat_statements/expected/oldextversions.out
@@ -342,4 +342,70 @@ SELECT pg_stat_statements_reset() IS NOT NULL AS t;
  t
 (1 row)
 
+-- New functions and views for pg_stat_statements in 1.12
+AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
+\d pg_stat_statements
+                             View "public.pg_stat_statements"
+            Column             |           Type           | Collation | Nullable | Default 
+-------------------------------+--------------------------+-----------+----------+---------
+ userid                        | oid                      |           |          | 
+ dbid                          | oid                      |           |          | 
+ toplevel                      | boolean                  |           |          | 
+ queryid                       | bigint                   |           |          | 
+ query                         | text                     |           |          | 
+ plans                         | bigint                   |           |          | 
+ total_plan_time               | double precision         |           |          | 
+ min_plan_time                 | double precision         |           |          | 
+ max_plan_time                 | double precision         |           |          | 
+ mean_plan_time                | double precision         |           |          | 
+ stddev_plan_time              | double precision         |           |          | 
+ calls                         | bigint                   |           |          | 
+ total_exec_time               | double precision         |           |          | 
+ min_exec_time                 | double precision         |           |          | 
+ max_exec_time                 | double precision         |           |          | 
+ mean_exec_time                | double precision         |           |          | 
+ stddev_exec_time              | double precision         |           |          | 
+ rows                          | bigint                   |           |          | 
+ shared_blks_hit               | bigint                   |           |          | 
+ shared_blks_read              | bigint                   |           |          | 
+ shared_blks_dirtied           | bigint                   |           |          | 
+ shared_blks_written           | bigint                   |           |          | 
+ local_blks_hit                | bigint                   |           |          | 
+ local_blks_read               | bigint                   |           |          | 
+ local_blks_dirtied            | bigint                   |           |          | 
+ local_blks_written            | bigint                   |           |          | 
+ temp_blks_read                | bigint                   |           |          | 
+ temp_blks_written             | bigint                   |           |          | 
+ shared_blk_read_time          | double precision         |           |          | 
+ shared_blk_write_time         | double precision         |           |          | 
+ local_blk_read_time           | double precision         |           |          | 
+ local_blk_write_time          | double precision         |           |          | 
+ temp_blk_read_time            | double precision         |           |          | 
+ temp_blk_write_time           | double precision         |           |          | 
+ wal_records                   | bigint                   |           |          | 
+ wal_fpi                       | bigint                   |           |          | 
+ wal_bytes                     | numeric                  |           |          | 
+ jit_functions                 | bigint                   |           |          | 
+ jit_generation_time           | double precision         |           |          | 
+ jit_inlining_count            | bigint                   |           |          | 
+ jit_inlining_time             | double precision         |           |          | 
+ jit_optimization_count        | bigint                   |           |          | 
+ jit_optimization_time         | double precision         |           |          | 
+ jit_emission_count            | bigint                   |           |          | 
+ jit_emission_time             | double precision         |           |          | 
+ jit_deform_count              | bigint                   |           |          | 
+ jit_deform_time               | double precision         |           |          | 
+ parallelized_queries_planned  | bigint                   |           |          | 
+ parallelized_queries_launched | bigint                   |           |          | 
+ parallelized_workers_planned  | bigint                   |           |          | 
+ parallelized_workers_launched | bigint                   |           |          | 
+ stats_since                   | timestamp with time zone |           |          | 
+ minmax_stats_since            | timestamp with time zone |           |          | 
+
+SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
+ has_data 
+----------
+ t
+(1 row)
+
 DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/expected/parallel.out b/contrib/pg_stat_statements/expected/parallel.out
new file mode 100644
index 0000000000..6e7c8ffb46
--- /dev/null
+++ b/contrib/pg_stat_statements/expected/parallel.out
@@ -0,0 +1,35 @@
+--
+-- Validate parallelization generation metrics
+--
+SET parallel_setup_cost TO 0;
+SET min_parallel_table_scan_size TO '100kB';
+SET pg_stat_statements.track_utility = FALSE;
+CREATE TABLE pgss_parallel_tab (a int);
+INSERT INTO pgss_parallel_tab SELECT generate_series(1, 10_000);
+SELECT count(*) FROM pgss_parallel_tab;
+ count 
+-------
+ 10000
+(1 row)
+
+DROP TABLE pgss_parallel_tab;
+-- Check parallelization metrics are generated for the SELECT statement
+SELECT query,
+  parallelized_queries_planned > 0 AS parallelized_queries_planned_generated,
+  parallelized_queries_launched > 0 AS parallelized_queries_launched_generated,
+  parallelized_workers_planned > 0 AS parallelized_workers_planned_generated,
+  parallelized_workers_launched > 0 AS parallelized_workers_launched_generated
+FROM pg_stat_statements
+WHERE query LIKE 'SELECT count%'
+ORDER BY query COLLATE "C";
+                 query                  | parallelized_queries_planned_generated | parallelized_queries_launched_generated | parallelized_workers_planned_generated | parallelized_workers_launched_generated 
+----------------------------------------+----------------------------------------+-----------------------------------------+----------------------------------------+-----------------------------------------
+ SELECT count(*) FROM pgss_parallel_tab | t                                      | t                                       | t                                      | t
+(1 row)
+
+SELECT pg_stat_statements_reset() IS NOT NULL AS t;
+ t 
+---
+ t
+(1 row)
+
diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
new file mode 100644
index 0000000000..fe6e81eb0f
--- /dev/null
+++ b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
@@ -0,0 +1,77 @@
+/* contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_stat_statements UPDATE TO '1.12'" to load this file. \quit
+
+/* First we have to remove them from the extension */
+ALTER EXTENSION pg_stat_statements DROP VIEW pg_stat_statements;
+ALTER EXTENSION pg_stat_statements DROP FUNCTION pg_stat_statements(boolean);
+
+/* Then we can drop them */
+DROP VIEW pg_stat_statements;
+DROP FUNCTION pg_stat_statements(boolean);
+
+/* Now redefine */
+CREATE FUNCTION pg_stat_statements(IN showtext boolean,
+    OUT userid oid,
+    OUT dbid oid,
+    OUT toplevel bool,
+    OUT queryid bigint,
+    OUT query text,
+    OUT plans int8,
+    OUT total_plan_time float8,
+    OUT min_plan_time float8,
+    OUT max_plan_time float8,
+    OUT mean_plan_time float8,
+    OUT stddev_plan_time float8,
+    OUT calls int8,
+    OUT total_exec_time float8,
+    OUT min_exec_time float8,
+    OUT max_exec_time float8,
+    OUT mean_exec_time float8,
+    OUT stddev_exec_time float8,
+    OUT rows int8,
+    OUT shared_blks_hit int8,
+    OUT shared_blks_read int8,
+    OUT shared_blks_dirtied int8,
+    OUT shared_blks_written int8,
+    OUT local_blks_hit int8,
+    OUT local_blks_read int8,
+    OUT local_blks_dirtied int8,
+    OUT local_blks_written int8,
+    OUT temp_blks_read int8,
+    OUT temp_blks_written int8,
+    OUT shared_blk_read_time float8,
+    OUT shared_blk_write_time float8,
+    OUT local_blk_read_time float8,
+    OUT local_blk_write_time float8,
+    OUT temp_blk_read_time float8,
+    OUT temp_blk_write_time float8,
+    OUT wal_records int8,
+    OUT wal_fpi int8,
+    OUT wal_bytes numeric,
+    OUT jit_functions int8,
+    OUT jit_generation_time float8,
+    OUT jit_inlining_count int8,
+    OUT jit_inlining_time float8,
+    OUT jit_optimization_count int8,
+    OUT jit_optimization_time float8,
+    OUT jit_emission_count int8,
+    OUT jit_emission_time float8,
+    OUT jit_deform_count int8,
+    OUT jit_deform_time float8,
+    OUT parallelized_queries_planned int8,
+    OUT parallelized_queries_launched int8,
+    OUT parallelized_workers_planned int8,
+    OUT parallelized_workers_launched int8,
+    OUT stats_since timestamp with time zone,
+    OUT minmax_stats_since timestamp with time zone
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_stat_statements_1_12'
+LANGUAGE C STRICT VOLATILE PARALLEL SAFE;
+
+CREATE VIEW pg_stat_statements AS
+  SELECT * FROM pg_stat_statements(true);
+
+GRANT SELECT ON pg_stat_statements TO PUBLIC;
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 5765ef49b4..939a27e829 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -113,6 +113,7 @@ typedef enum pgssVersion
 	PGSS_V1_9,
 	PGSS_V1_10,
 	PGSS_V1_11,
+	PGSS_V1_12,
 } pgssVersion;
 
 typedef enum pgssStoreKind
@@ -204,6 +205,10 @@ typedef struct Counters
 	int64		jit_emission_count; /* number of times emission time has been
 									 * > 0 */
 	double		jit_emission_time;	/* total time to emit jit code */
+	int64       parallelized_queries_planned;	/* # of times query was planned to use parallelism */
+	int64       parallelized_queries_launched;	/* # of times query was executed using parallelism */
+	int64       parallelized_workers_planned;	/* # of parallel workers planned */
+	int64       parallelized_workers_launched;	/* # of parallel workers launched */
 } Counters;
 
 /*
@@ -317,6 +322,7 @@ PG_FUNCTION_INFO_V1(pg_stat_statements_1_8);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_9);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_10);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_11);
+PG_FUNCTION_INFO_V1(pg_stat_statements_1_12);
 PG_FUNCTION_INFO_V1(pg_stat_statements);
 PG_FUNCTION_INFO_V1(pg_stat_statements_info);
 
@@ -347,7 +353,11 @@ static void pgss_store(const char *query, uint64 queryId,
 					   const BufferUsage *bufusage,
 					   const WalUsage *walusage,
 					   const struct JitInstrumentation *jitusage,
-					   JumbleState *jstate);
+					   JumbleState *jstate,
+					   bool parallelized_queries_planned,
+					   bool parallelized_queries_launched,
+					   int parallelized_workers_planned,
+					   int parallelized_workers_launched);
 static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
 										pgssVersion api_version,
 										bool showtext);
@@ -867,7 +877,11 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 				   NULL,
 				   NULL,
 				   NULL,
-				   jstate);
+				   jstate,
+				   false,
+				   false,
+				   0,
+				   0);
 }
 
 /*
@@ -945,7 +959,11 @@ pgss_planner(Query *parse,
 				   &bufusage,
 				   &walusage,
 				   NULL,
-				   NULL);
+				   NULL,
+				   false,
+				   false,
+				   0,
+				   0);
 	}
 	else
 	{
@@ -1078,7 +1096,11 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
 				   &queryDesc->totaltime->bufusage,
 				   &queryDesc->totaltime->walusage,
 				   queryDesc->estate->es_jit ? &queryDesc->estate->es_jit->instr : NULL,
-				   NULL);
+				   NULL,
+				   queryDesc->plannedstmt->parallelModeNeeded,
+				   queryDesc->estate->es_used_parallel_mode,
+				   queryDesc->estate->es_parallelized_workers_planned,
+				   queryDesc->estate->es_parallelized_workers_launched);
 	}
 
 	if (prev_ExecutorEnd)
@@ -1209,7 +1231,11 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 				   &bufusage,
 				   &walusage,
 				   NULL,
-				   NULL);
+				   NULL,
+				   false,
+				   false,
+				   0,
+				   0);
 	}
 	else
 	{
@@ -1270,7 +1296,11 @@ pgss_store(const char *query, uint64 queryId,
 		   const BufferUsage *bufusage,
 		   const WalUsage *walusage,
 		   const struct JitInstrumentation *jitusage,
-		   JumbleState *jstate)
+		   JumbleState *jstate,
+		   bool parallelized_queries_planned,
+		   bool parallelized_queries_launched,
+		   int parallelized_workers_planned,
+		   int parallelized_workers_launched)
 {
 	pgssHashKey key;
 	pgssEntry  *entry;
@@ -1472,6 +1502,17 @@ pgss_store(const char *query, uint64 queryId,
 				entry->counters.jit_emission_count++;
 			entry->counters.jit_emission_time += INSTR_TIME_GET_MILLISEC(jitusage->emission_counter);
 		}
+		/* inc parallel counters */
+		if (parallelized_queries_planned)
+		{
+			entry->counters.parallelized_queries_planned += 1;
+		}
+		if (parallelized_queries_launched)
+		{
+			entry->counters.parallelized_queries_launched += 1;
+		}
+		entry->counters.parallelized_workers_planned += parallelized_workers_planned;
+		entry->counters.parallelized_workers_launched += parallelized_workers_launched;
 
 		SpinLockRelease(&entry->mutex);
 	}
@@ -1539,7 +1580,8 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
 #define PG_STAT_STATEMENTS_COLS_V1_9	33
 #define PG_STAT_STATEMENTS_COLS_V1_10	43
 #define PG_STAT_STATEMENTS_COLS_V1_11	49
-#define PG_STAT_STATEMENTS_COLS			49	/* maximum of above */
+#define PG_STAT_STATEMENTS_COLS_V1_12	53
+#define PG_STAT_STATEMENTS_COLS			53	/* maximum of above */
 
 /*
  * Retrieve statement statistics.
@@ -1551,6 +1593,16 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
  * expected API version is identified by embedding it in the C name of the
  * function.  Unfortunately we weren't bright enough to do that for 1.1.
  */
+Datum
+pg_stat_statements_1_12(PG_FUNCTION_ARGS)
+{
+	bool		showtext = PG_GETARG_BOOL(0);
+
+	pg_stat_statements_internal(fcinfo, PGSS_V1_12, showtext);
+
+	return (Datum) 0;
+}
+
 Datum
 pg_stat_statements_1_11(PG_FUNCTION_ARGS)
 {
@@ -1695,6 +1747,10 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 			if (api_version != PGSS_V1_11)
 				elog(ERROR, "incorrect number of output arguments");
 			break;
+		case PG_STAT_STATEMENTS_COLS_V1_12:
+			if (api_version != PGSS_V1_12)
+				elog(ERROR, "incorrect number of output arguments");
+			break;
 		default:
 			elog(ERROR, "incorrect number of output arguments");
 	}
@@ -1932,6 +1988,16 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 		{
 			values[i++] = Int64GetDatumFast(tmp.jit_deform_count);
 			values[i++] = Float8GetDatumFast(tmp.jit_deform_time);
+		}
+		if (api_version >= PGSS_V1_12)
+		{
+			values[i++] = Int64GetDatumFast(tmp.parallelized_queries_planned);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_queries_launched);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_workers_planned);
+			values[i++] = Int64GetDatumFast(tmp.parallelized_workers_launched);
+		}
+		if (api_version >= PGSS_V1_11)
+		{
 			values[i++] = TimestampTzGetDatum(stats_since);
 			values[i++] = TimestampTzGetDatum(minmax_stats_since);
 		}
@@ -1944,6 +2010,7 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 					 api_version == PGSS_V1_9 ? PG_STAT_STATEMENTS_COLS_V1_9 :
 					 api_version == PGSS_V1_10 ? PG_STAT_STATEMENTS_COLS_V1_10 :
 					 api_version == PGSS_V1_11 ? PG_STAT_STATEMENTS_COLS_V1_11 :
+					 api_version == PGSS_V1_12 ? PG_STAT_STATEMENTS_COLS_V1_12 :
 					 -1 /* fail if you forget to update this assert */ ));
 
 		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
diff --git a/contrib/pg_stat_statements/pg_stat_statements.control b/contrib/pg_stat_statements/pg_stat_statements.control
index 8a76106ec6..d45ebc12e3 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.control
+++ b/contrib/pg_stat_statements/pg_stat_statements.control
@@ -1,5 +1,5 @@
 # pg_stat_statements extension
 comment = 'track planning and execution statistics of all SQL statements executed'
-default_version = '1.11'
+default_version = '1.12'
 module_pathname = '$libdir/pg_stat_statements'
 relocatable = true
diff --git a/contrib/pg_stat_statements/sql/oldextversions.sql b/contrib/pg_stat_statements/sql/oldextversions.sql
index 38d5505d0d..13b8ca2858 100644
--- a/contrib/pg_stat_statements/sql/oldextversions.sql
+++ b/contrib/pg_stat_statements/sql/oldextversions.sql
@@ -58,4 +58,9 @@ SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
 SELECT pg_get_functiondef('pg_stat_statements_reset'::regproc);
 SELECT pg_stat_statements_reset() IS NOT NULL AS t;
 
+-- New functions and views for pg_stat_statements in 1.12
+AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
+\d pg_stat_statements
+SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
+
 DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/sql/parallel.sql b/contrib/pg_stat_statements/sql/parallel.sql
new file mode 100644
index 0000000000..8b32edffb5
--- /dev/null
+++ b/contrib/pg_stat_statements/sql/parallel.sql
@@ -0,0 +1,24 @@
+--
+-- Validate parallelization generation metrics
+--
+
+SET parallel_setup_cost TO 0;
+SET min_parallel_table_scan_size TO '100kB';
+SET pg_stat_statements.track_utility = FALSE;
+
+CREATE TABLE pgss_parallel_tab (a int);
+INSERT INTO pgss_parallel_tab SELECT generate_series(1, 10_000);
+SELECT count(*) FROM pgss_parallel_tab;
+DROP TABLE pgss_parallel_tab;
+
+-- Check parallelization metrics are generated for the SELECT statement
+SELECT query,
+  parallelized_queries_planned > 0 AS parallelized_queries_planned_generated,
+  parallelized_queries_launched > 0 AS parallelized_queries_launched_generated,
+  parallelized_workers_planned > 0 AS parallelized_workers_planned_generated,
+  parallelized_workers_launched > 0 AS parallelized_workers_launched_generated
+FROM pg_stat_statements
+WHERE query LIKE 'SELECT count%'
+ORDER BY query COLLATE "C";
+
+SELECT pg_stat_statements_reset() IS NOT NULL AS t;
diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 9b0aff73b1..ce66fe1b16 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -527,6 +527,42 @@
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_queries_planned</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of times the statement was planned to use parallelism.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_queries_launched</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of times that the statement was executed using parallelism
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallelized_workers_planned</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallel workers planned for the query.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_workers_launched</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallel workers executed for the query.
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stats_since</structfield> <type>timestamp with time zone</type>
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 1908481999..634ba5caed 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -158,6 +158,7 @@ CreateExecutorState(void)
 	estate->es_sourceText = NULL;
 
 	estate->es_use_parallel_mode = false;
+	estate->es_used_parallel_mode = false;
 
 	estate->es_jit_flags = 0;
 	estate->es_jit = NULL;
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 0fb915175a..489bfbfe87 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -182,6 +182,8 @@ ExecGather(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			if(pcxt->nworkers_launched > 0)
+				estate->es_used_parallel_mode = true;
 			estate->es_parallelized_workers_launched += pcxt->nworkers_launched;
 			estate->es_parallelized_workers_planned += pcxt->nworkers_to_launch;
 
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 149ab23d90..df0a36d3ac 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -223,6 +223,8 @@ ExecGatherMerge(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			if(pcxt->nworkers_launched > 0)
+				estate->es_used_parallel_mode = true;
 			estate->es_parallelized_workers_launched += pcxt->nworkers_launched;
 			estate->es_parallelized_workers_planned += pcxt->nworkers_to_launch;
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index f898590ece..9e67de4a4d 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -708,6 +708,7 @@ typedef struct EState
 
 	bool		es_use_parallel_mode;	/* can we use parallel workers? */
 
+	bool		es_used_parallel_mode;	/* was executed in parallel */
 	int			es_parallelized_workers_launched;
 	int			es_parallelized_workers_planned;
 
-- 
2.46.2

From 5dc567cda5ad9e0c41532ef6ce5cc5f1808e974e Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Tue, 8 Oct 2024 15:52:38 +0900
Subject: [PATCH v4 1/3] Introduce two new counters in EState for parallel
 workers

They will be used by some follow-up patches to populate other parts of
the system with this data extracted from the executor.
---
 src/include/nodes/execnodes.h          | 5 +++++
 src/backend/executor/execUtils.c       | 2 ++
 src/backend/executor/nodeGather.c      | 7 +++++++
 src/backend/executor/nodeGatherMerge.c | 7 +++++++
 4 files changed, 21 insertions(+)

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index aab59d681c..e4698a28c4 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -708,6 +708,11 @@ typedef struct EState
 
 	bool		es_use_parallel_mode;	/* can we use parallel workers? */
 
+	int			es_parallel_workers_to_launch;	/* number of workers to
+												 * launch. */
+	int			es_parallel_workers_launched;	/* number of workers actually
+												 * launched. */
+
 	/* The per-query shared memory area to use for parallel execution. */
 	struct dsa_area *es_query_dsa;
 
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 5737f9f4eb..6712302ec8 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -158,6 +158,8 @@ CreateExecutorState(void)
 	estate->es_sourceText = NULL;
 
 	estate->es_use_parallel_mode = false;
+	estate->es_parallel_workers_to_launch = 0;
+	estate->es_parallel_workers_launched = 0;
 
 	estate->es_jit_flags = 0;
 	estate->es_jit = NULL;
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 5d4ffe989c..7f7edc7f9f 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -182,6 +182,13 @@ ExecGather(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			/*
+			 * Count number of workers originally wanted and actually
+			 * launched.
+			 */
+			estate->es_parallel_workers_to_launch += pcxt->nworkers_to_launch;
+			estate->es_parallel_workers_launched += pcxt->nworkers_launched;
+
 			/* Set up tuple queue readers to read the results. */
 			if (pcxt->nworkers_launched > 0)
 			{
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 45f6017c29..bc99c0b448 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -223,6 +223,13 @@ ExecGatherMerge(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			/*
+			 * Count number of workers originally wanted and actually
+			 * launched.
+			 */
+			estate->es_parallel_workers_to_launch += pcxt->nworkers_to_launch;
+			estate->es_parallel_workers_launched += pcxt->nworkers_launched;
+
 			/* Set up tuple queue readers to read the results. */
 			if (pcxt->nworkers_launched > 0)
 			{
-- 
2.45.2

From a28475ff5b1e17ee7295a3daabc79111c30b96d3 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Tue, 8 Oct 2024 15:56:22 +0900
Subject: [PATCH v4 2/3] Add parallel columns to pg_stat_statements

---
 doc/src/sgml/pgstatstatements.sgml            | 18 +++++
 contrib/pg_stat_statements/Makefile           |  6 +-
 .../expected/oldextversions.out               | 64 ++++++++++++++++
 .../pg_stat_statements/expected/parallel.out  | 34 +++++++++
 contrib/pg_stat_statements/meson.build        |  2 +
 .../pg_stat_statements--1.11--1.12.sql        | 75 +++++++++++++++++++
 .../pg_stat_statements/pg_stat_statements.c   | 60 +++++++++++++--
 .../pg_stat_statements.control                |  2 +-
 .../pg_stat_statements/sql/oldextversions.sql |  5 ++
 contrib/pg_stat_statements/sql/parallel.sql   | 26 +++++++
 10 files changed, 281 insertions(+), 11 deletions(-)
 create mode 100644 contrib/pg_stat_statements/expected/parallel.out
 create mode 100644 contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
 create mode 100644 contrib/pg_stat_statements/sql/parallel.sql

diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 9b0aff73b1..501b468e9a 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -527,6 +527,24 @@
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_workers_to_launch</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallel workers planned to be launched
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_workers_launched</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of parallel workers actually launched
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stats_since</structfield> <type>timestamp with time zone</type>
diff --git a/contrib/pg_stat_statements/Makefile b/contrib/pg_stat_statements/Makefile
index 1622b43ded..241c02587b 100644
--- a/contrib/pg_stat_statements/Makefile
+++ b/contrib/pg_stat_statements/Makefile
@@ -7,7 +7,7 @@ OBJS = \
 
 EXTENSION = pg_stat_statements
 DATA = pg_stat_statements--1.4.sql \
-	pg_stat_statements--1.10--1.11.sql \
+	pg_stat_statements--1.11--1.12.sql pg_stat_statements--1.10--1.11.sql \
 	pg_stat_statements--1.9--1.10.sql pg_stat_statements--1.8--1.9.sql \
 	pg_stat_statements--1.7--1.8.sql pg_stat_statements--1.6--1.7.sql \
 	pg_stat_statements--1.5--1.6.sql pg_stat_statements--1.4--1.5.sql \
@@ -19,8 +19,8 @@ LDFLAGS_SL += $(filter -lm, $(LIBS))
 
 REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/pg_stat_statements/pg_stat_statements.conf
 REGRESS = select dml cursors utility level_tracking planning \
-	user_activity wal entry_timestamp privileges extended cleanup \
-	oldextversions
+	user_activity wal entry_timestamp privileges extended \
+	parallel cleanup oldextversions
 # Disabled because these tests require "shared_preload_libraries=pg_stat_statements",
 # which typical installcheck users do not have (e.g. buildfarm clients).
 NO_INSTALLCHECK = 1
diff --git a/contrib/pg_stat_statements/expected/oldextversions.out b/contrib/pg_stat_statements/expected/oldextversions.out
index 5842c930e5..0c60fc8127 100644
--- a/contrib/pg_stat_statements/expected/oldextversions.out
+++ b/contrib/pg_stat_statements/expected/oldextversions.out
@@ -342,4 +342,68 @@ SELECT pg_stat_statements_reset() IS NOT NULL AS t;
  t
 (1 row)
 
+-- New functions and views for pg_stat_statements in 1.12
+AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
+\d pg_stat_statements
+                            View "public.pg_stat_statements"
+           Column           |           Type           | Collation | Nullable | Default 
+----------------------------+--------------------------+-----------+----------+---------
+ userid                     | oid                      |           |          | 
+ dbid                       | oid                      |           |          | 
+ toplevel                   | boolean                  |           |          | 
+ queryid                    | bigint                   |           |          | 
+ query                      | text                     |           |          | 
+ plans                      | bigint                   |           |          | 
+ total_plan_time            | double precision         |           |          | 
+ min_plan_time              | double precision         |           |          | 
+ max_plan_time              | double precision         |           |          | 
+ mean_plan_time             | double precision         |           |          | 
+ stddev_plan_time           | double precision         |           |          | 
+ calls                      | bigint                   |           |          | 
+ total_exec_time            | double precision         |           |          | 
+ min_exec_time              | double precision         |           |          | 
+ max_exec_time              | double precision         |           |          | 
+ mean_exec_time             | double precision         |           |          | 
+ stddev_exec_time           | double precision         |           |          | 
+ rows                       | bigint                   |           |          | 
+ shared_blks_hit            | bigint                   |           |          | 
+ shared_blks_read           | bigint                   |           |          | 
+ shared_blks_dirtied        | bigint                   |           |          | 
+ shared_blks_written        | bigint                   |           |          | 
+ local_blks_hit             | bigint                   |           |          | 
+ local_blks_read            | bigint                   |           |          | 
+ local_blks_dirtied         | bigint                   |           |          | 
+ local_blks_written         | bigint                   |           |          | 
+ temp_blks_read             | bigint                   |           |          | 
+ temp_blks_written          | bigint                   |           |          | 
+ shared_blk_read_time       | double precision         |           |          | 
+ shared_blk_write_time      | double precision         |           |          | 
+ local_blk_read_time        | double precision         |           |          | 
+ local_blk_write_time       | double precision         |           |          | 
+ temp_blk_read_time         | double precision         |           |          | 
+ temp_blk_write_time        | double precision         |           |          | 
+ wal_records                | bigint                   |           |          | 
+ wal_fpi                    | bigint                   |           |          | 
+ wal_bytes                  | numeric                  |           |          | 
+ jit_functions              | bigint                   |           |          | 
+ jit_generation_time        | double precision         |           |          | 
+ jit_inlining_count         | bigint                   |           |          | 
+ jit_inlining_time          | double precision         |           |          | 
+ jit_optimization_count     | bigint                   |           |          | 
+ jit_optimization_time      | double precision         |           |          | 
+ jit_emission_count         | bigint                   |           |          | 
+ jit_emission_time          | double precision         |           |          | 
+ jit_deform_count           | bigint                   |           |          | 
+ jit_deform_time            | double precision         |           |          | 
+ parallel_workers_to_launch | bigint                   |           |          | 
+ parallel_workers_launched  | bigint                   |           |          | 
+ stats_since                | timestamp with time zone |           |          | 
+ minmax_stats_since         | timestamp with time zone |           |          | 
+
+SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
+ has_data 
+----------
+ t
+(1 row)
+
 DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/expected/parallel.out b/contrib/pg_stat_statements/expected/parallel.out
new file mode 100644
index 0000000000..8af3bd2c91
--- /dev/null
+++ b/contrib/pg_stat_statements/expected/parallel.out
@@ -0,0 +1,34 @@
+--
+-- Tests for parallel statistics
+--
+SET pg_stat_statements.track_utility = FALSE;
+-- encourage use of parallel plans
+SET parallel_setup_cost = 0;
+SET parallel_tuple_cost = 0;
+SET min_parallel_table_scan_size = 0;
+SET max_parallel_workers_per_gather = 2;
+CREATE TABLE pgss_parallel_tab (a int);
+SELECT pg_stat_statements_reset() IS NOT NULL AS t;
+ t 
+---
+ t
+(1 row)
+
+SELECT count(*) FROM pgss_parallel_tab;
+ count 
+-------
+     0
+(1 row)
+
+SELECT query,
+  parallel_workers_to_launch > 0 AS has_workers_to_launch,
+  parallel_workers_launched > 0 AS has_workers_launched
+  FROM pg_stat_statements
+  WHERE query ~ 'SELECT count'
+  ORDER BY query COLLATE "C";
+                 query                  | has_workers_to_launch | has_workers_launched 
+----------------------------------------+-----------------------+----------------------
+ SELECT count(*) FROM pgss_parallel_tab | t                     | t
+(1 row)
+
+DROP TABLE pgss_parallel_tab;
diff --git a/contrib/pg_stat_statements/meson.build b/contrib/pg_stat_statements/meson.build
index e14669ca15..e659b5e2b7 100644
--- a/contrib/pg_stat_statements/meson.build
+++ b/contrib/pg_stat_statements/meson.build
@@ -21,6 +21,7 @@ contrib_targets += pg_stat_statements
 install_data(
   'pg_stat_statements.control',
   'pg_stat_statements--1.4.sql',
+  'pg_stat_statements--1.11--1.12.sql',
   'pg_stat_statements--1.10--1.11.sql',
   'pg_stat_statements--1.9--1.10.sql',
   'pg_stat_statements--1.8--1.9.sql',
@@ -52,6 +53,7 @@ tests += {
       'entry_timestamp',
       'privileges',
       'extended',
+      'parallel',
       'cleanup',
       'oldextversions',
     ],
diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
new file mode 100644
index 0000000000..80e6be2544
--- /dev/null
+++ b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
@@ -0,0 +1,75 @@
+/* contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_stat_statements UPDATE TO '1.12'" to load this file. \quit
+
+/* First we have to remove them from the extension */
+ALTER EXTENSION pg_stat_statements DROP VIEW pg_stat_statements;
+ALTER EXTENSION pg_stat_statements DROP FUNCTION pg_stat_statements(boolean);
+
+/* Then we can drop them */
+DROP VIEW pg_stat_statements;
+DROP FUNCTION pg_stat_statements(boolean);
+
+/* Now redefine */
+CREATE FUNCTION pg_stat_statements(IN showtext boolean,
+    OUT userid oid,
+    OUT dbid oid,
+    OUT toplevel bool,
+    OUT queryid bigint,
+    OUT query text,
+    OUT plans int8,
+    OUT total_plan_time float8,
+    OUT min_plan_time float8,
+    OUT max_plan_time float8,
+    OUT mean_plan_time float8,
+    OUT stddev_plan_time float8,
+    OUT calls int8,
+    OUT total_exec_time float8,
+    OUT min_exec_time float8,
+    OUT max_exec_time float8,
+    OUT mean_exec_time float8,
+    OUT stddev_exec_time float8,
+    OUT rows int8,
+    OUT shared_blks_hit int8,
+    OUT shared_blks_read int8,
+    OUT shared_blks_dirtied int8,
+    OUT shared_blks_written int8,
+    OUT local_blks_hit int8,
+    OUT local_blks_read int8,
+    OUT local_blks_dirtied int8,
+    OUT local_blks_written int8,
+    OUT temp_blks_read int8,
+    OUT temp_blks_written int8,
+    OUT shared_blk_read_time float8,
+    OUT shared_blk_write_time float8,
+    OUT local_blk_read_time float8,
+    OUT local_blk_write_time float8,
+    OUT temp_blk_read_time float8,
+    OUT temp_blk_write_time float8,
+    OUT wal_records int8,
+    OUT wal_fpi int8,
+    OUT wal_bytes numeric,
+    OUT jit_functions int8,
+    OUT jit_generation_time float8,
+    OUT jit_inlining_count int8,
+    OUT jit_inlining_time float8,
+    OUT jit_optimization_count int8,
+    OUT jit_optimization_time float8,
+    OUT jit_emission_count int8,
+    OUT jit_emission_time float8,
+    OUT jit_deform_count int8,
+    OUT jit_deform_time float8,
+    OUT parallel_workers_to_launch int8,
+    OUT parallel_workers_launched int8,
+    OUT stats_since timestamp with time zone,
+    OUT minmax_stats_since timestamp with time zone
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_stat_statements_1_12'
+LANGUAGE C STRICT VOLATILE PARALLEL SAFE;
+
+CREATE VIEW pg_stat_statements AS
+  SELECT * FROM pg_stat_statements(true);
+
+GRANT SELECT ON pg_stat_statements TO PUBLIC;
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 5765ef49b4..773b821911 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -113,6 +113,7 @@ typedef enum pgssVersion
 	PGSS_V1_9,
 	PGSS_V1_10,
 	PGSS_V1_11,
+	PGSS_V1_12,
 } pgssVersion;
 
 typedef enum pgssStoreKind
@@ -204,6 +205,10 @@ typedef struct Counters
 	int64		jit_emission_count; /* number of times emission time has been
 									 * > 0 */
 	double		jit_emission_time;	/* total time to emit jit code */
+	int64       parallel_workers_to_launch;	/* # of parallel workers planned to
+											 * be launched */
+	int64       parallel_workers_launched;	/* # of parallel workers actually
+											 * launched */
 } Counters;
 
 /*
@@ -317,6 +322,7 @@ PG_FUNCTION_INFO_V1(pg_stat_statements_1_8);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_9);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_10);
 PG_FUNCTION_INFO_V1(pg_stat_statements_1_11);
+PG_FUNCTION_INFO_V1(pg_stat_statements_1_12);
 PG_FUNCTION_INFO_V1(pg_stat_statements);
 PG_FUNCTION_INFO_V1(pg_stat_statements_info);
 
@@ -347,7 +353,9 @@ static void pgss_store(const char *query, uint64 queryId,
 					   const BufferUsage *bufusage,
 					   const WalUsage *walusage,
 					   const struct JitInstrumentation *jitusage,
-					   JumbleState *jstate);
+					   JumbleState *jstate,
+					   int parallel_workers_to_launch,
+					   int parallel_workers_launched);
 static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
 										pgssVersion api_version,
 										bool showtext);
@@ -867,7 +875,9 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 				   NULL,
 				   NULL,
 				   NULL,
-				   jstate);
+				   jstate,
+				   0,
+				   0);
 }
 
 /*
@@ -945,7 +955,9 @@ pgss_planner(Query *parse,
 				   &bufusage,
 				   &walusage,
 				   NULL,
-				   NULL);
+				   NULL,
+				   0,
+				   0);
 	}
 	else
 	{
@@ -1078,7 +1090,9 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
 				   &queryDesc->totaltime->bufusage,
 				   &queryDesc->totaltime->walusage,
 				   queryDesc->estate->es_jit ? &queryDesc->estate->es_jit->instr : NULL,
-				   NULL);
+				   NULL,
+				   queryDesc->estate->es_parallel_workers_to_launch,
+				   queryDesc->estate->es_parallel_workers_launched);
 	}
 
 	if (prev_ExecutorEnd)
@@ -1209,7 +1223,9 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 				   &bufusage,
 				   &walusage,
 				   NULL,
-				   NULL);
+				   NULL,
+				   0,
+				   0);
 	}
 	else
 	{
@@ -1270,7 +1286,9 @@ pgss_store(const char *query, uint64 queryId,
 		   const BufferUsage *bufusage,
 		   const WalUsage *walusage,
 		   const struct JitInstrumentation *jitusage,
-		   JumbleState *jstate)
+		   JumbleState *jstate,
+		   int parallel_workers_to_launch,
+		   int parallel_workers_launched)
 {
 	pgssHashKey key;
 	pgssEntry  *entry;
@@ -1473,6 +1491,10 @@ pgss_store(const char *query, uint64 queryId,
 			entry->counters.jit_emission_time += INSTR_TIME_GET_MILLISEC(jitusage->emission_counter);
 		}
 
+		/* parallel worker counters */
+		entry->counters.parallel_workers_to_launch += parallel_workers_to_launch;
+		entry->counters.parallel_workers_launched += parallel_workers_launched;
+
 		SpinLockRelease(&entry->mutex);
 	}
 
@@ -1539,7 +1561,8 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
 #define PG_STAT_STATEMENTS_COLS_V1_9	33
 #define PG_STAT_STATEMENTS_COLS_V1_10	43
 #define PG_STAT_STATEMENTS_COLS_V1_11	49
-#define PG_STAT_STATEMENTS_COLS			49	/* maximum of above */
+#define PG_STAT_STATEMENTS_COLS_V1_12	51
+#define PG_STAT_STATEMENTS_COLS			51	/* maximum of above */
 
 /*
  * Retrieve statement statistics.
@@ -1551,6 +1574,16 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
  * expected API version is identified by embedding it in the C name of the
  * function.  Unfortunately we weren't bright enough to do that for 1.1.
  */
+Datum
+pg_stat_statements_1_12(PG_FUNCTION_ARGS)
+{
+	bool		showtext = PG_GETARG_BOOL(0);
+
+	pg_stat_statements_internal(fcinfo, PGSS_V1_12, showtext);
+
+	return (Datum) 0;
+}
+
 Datum
 pg_stat_statements_1_11(PG_FUNCTION_ARGS)
 {
@@ -1695,6 +1728,10 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 			if (api_version != PGSS_V1_11)
 				elog(ERROR, "incorrect number of output arguments");
 			break;
+		case PG_STAT_STATEMENTS_COLS_V1_12:
+			if (api_version != PGSS_V1_12)
+				elog(ERROR, "incorrect number of output arguments");
+			break;
 		default:
 			elog(ERROR, "incorrect number of output arguments");
 	}
@@ -1932,6 +1969,14 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 		{
 			values[i++] = Int64GetDatumFast(tmp.jit_deform_count);
 			values[i++] = Float8GetDatumFast(tmp.jit_deform_time);
+		}
+		if (api_version >= PGSS_V1_12)
+		{
+			values[i++] = Int64GetDatumFast(tmp.parallel_workers_to_launch);
+			values[i++] = Int64GetDatumFast(tmp.parallel_workers_launched);
+		}
+		if (api_version >= PGSS_V1_11)
+		{
 			values[i++] = TimestampTzGetDatum(stats_since);
 			values[i++] = TimestampTzGetDatum(minmax_stats_since);
 		}
@@ -1944,6 +1989,7 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 					 api_version == PGSS_V1_9 ? PG_STAT_STATEMENTS_COLS_V1_9 :
 					 api_version == PGSS_V1_10 ? PG_STAT_STATEMENTS_COLS_V1_10 :
 					 api_version == PGSS_V1_11 ? PG_STAT_STATEMENTS_COLS_V1_11 :
+					 api_version == PGSS_V1_12 ? PG_STAT_STATEMENTS_COLS_V1_12 :
 					 -1 /* fail if you forget to update this assert */ ));
 
 		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
diff --git a/contrib/pg_stat_statements/pg_stat_statements.control b/contrib/pg_stat_statements/pg_stat_statements.control
index 8a76106ec6..d45ebc12e3 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.control
+++ b/contrib/pg_stat_statements/pg_stat_statements.control
@@ -1,5 +1,5 @@
 # pg_stat_statements extension
 comment = 'track planning and execution statistics of all SQL statements executed'
-default_version = '1.11'
+default_version = '1.12'
 module_pathname = '$libdir/pg_stat_statements'
 relocatable = true
diff --git a/contrib/pg_stat_statements/sql/oldextversions.sql b/contrib/pg_stat_statements/sql/oldextversions.sql
index 38d5505d0d..13b8ca2858 100644
--- a/contrib/pg_stat_statements/sql/oldextversions.sql
+++ b/contrib/pg_stat_statements/sql/oldextversions.sql
@@ -58,4 +58,9 @@ SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
 SELECT pg_get_functiondef('pg_stat_statements_reset'::regproc);
 SELECT pg_stat_statements_reset() IS NOT NULL AS t;
 
+-- New functions and views for pg_stat_statements in 1.12
+AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
+\d pg_stat_statements
+SELECT count(*) > 0 AS has_data FROM pg_stat_statements;
+
 DROP EXTENSION pg_stat_statements;
diff --git a/contrib/pg_stat_statements/sql/parallel.sql b/contrib/pg_stat_statements/sql/parallel.sql
new file mode 100644
index 0000000000..4ce1573d13
--- /dev/null
+++ b/contrib/pg_stat_statements/sql/parallel.sql
@@ -0,0 +1,26 @@
+--
+-- Tests for parallel statistics
+--
+
+SET pg_stat_statements.track_utility = FALSE;
+
+-- encourage use of parallel plans
+SET parallel_setup_cost = 0;
+SET parallel_tuple_cost = 0;
+SET min_parallel_table_scan_size = 0;
+SET max_parallel_workers_per_gather = 2;
+
+CREATE TABLE pgss_parallel_tab (a int);
+
+SELECT pg_stat_statements_reset() IS NOT NULL AS t;
+
+SELECT count(*) FROM pgss_parallel_tab;
+
+SELECT query,
+  parallel_workers_to_launch > 0 AS has_workers_to_launch,
+  parallel_workers_launched > 0 AS has_workers_launched
+  FROM pg_stat_statements
+  WHERE query ~ 'SELECT count'
+  ORDER BY query COLLATE "C";
+
+DROP TABLE pgss_parallel_tab;
-- 
2.45.2

From c01361e32cbc4bc82a88c0568fa93a1a1565032b Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Tue, 8 Oct 2024 16:26:13 +0900
Subject: [PATCH v4 3/3] Introduce two more counters in pg_stat_statements

These track if a query has used parallelism at execution time, and if
parallelism was actually initially planned or not, incrementing
dedicated counters when reaching the executor path.
---
 src/include/nodes/execnodes.h                 |  1 +
 src/backend/executor/execUtils.c              |  1 +
 src/backend/executor/nodeGather.c             |  3 ++
 src/backend/executor/nodeGatherMerge.c        |  2 +
 doc/src/sgml/pgstatstatements.sgml            | 18 +++++++++
 .../expected/oldextversions.out               |  2 +
 .../pg_stat_statements/expected/parallel.out  | 10 +++--
 .../pg_stat_statements--1.11--1.12.sql        |  2 +
 .../pg_stat_statements/pg_stat_statements.c   | 38 +++++++++++++++----
 contrib/pg_stat_statements/sql/parallel.sql   |  4 +-
 10 files changed, 68 insertions(+), 13 deletions(-)

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index e4698a28c4..2a81fb1ead 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -707,6 +707,7 @@ typedef struct EState
 	struct EPQState *es_epq_active;
 
 	bool		es_use_parallel_mode;	/* can we use parallel workers? */
+	bool		es_used_parallel_mode;	/* was executed in parallel */
 
 	int			es_parallel_workers_to_launch;	/* number of workers to
 												 * launch. */
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 6712302ec8..f06d4eefd3 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -158,6 +158,7 @@ CreateExecutorState(void)
 	estate->es_sourceText = NULL;
 
 	estate->es_use_parallel_mode = false;
+	estate->es_used_parallel_mode = false;
 	estate->es_parallel_workers_to_launch = 0;
 	estate->es_parallel_workers_launched = 0;
 
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c
index 7f7edc7f9f..f33c837304 100644
--- a/src/backend/executor/nodeGather.c
+++ b/src/backend/executor/nodeGather.c
@@ -182,6 +182,9 @@ ExecGather(PlanState *pstate)
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
 
+			if (pcxt->nworkers_launched > 0)
+				estate->es_used_parallel_mode = true;
+
 			/*
 			 * Count number of workers originally wanted and actually
 			 * launched.
diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index bc99c0b448..671d6edb04 100644
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -222,6 +222,8 @@ ExecGatherMerge(PlanState *pstate)
 			LaunchParallelWorkers(pcxt);
 			/* We save # workers launched for the benefit of EXPLAIN */
 			node->nworkers_launched = pcxt->nworkers_launched;
+			 if (pcxt->nworkers_launched > 0)
+				 estate->es_used_parallel_mode = true;
 
 			/*
 			 * Count number of workers originally wanted and actually
diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 501b468e9a..4af09837cf 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -545,6 +545,24 @@
       </para></entry>
      </row>
 
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_queries_planned</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of times the statement was planned to use parallelism.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>parallel_queries_launched</structfield> <type>bigint</type>
+      </para>
+      <para>
+       Number of times that the statement was executed using parallelism
+      </para></entry>
+     </row>
+
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>stats_since</structfield> <type>timestamp with time zone</type>
diff --git a/contrib/pg_stat_statements/expected/oldextversions.out b/contrib/pg_stat_statements/expected/oldextversions.out
index 0c60fc8127..84e3f04d5f 100644
--- a/contrib/pg_stat_statements/expected/oldextversions.out
+++ b/contrib/pg_stat_statements/expected/oldextversions.out
@@ -397,6 +397,8 @@ AlTER EXTENSION pg_stat_statements UPDATE TO '1.12';
  jit_deform_time            | double precision         |           |          | 
  parallel_workers_to_launch | bigint                   |           |          | 
  parallel_workers_launched  | bigint                   |           |          | 
+ parallel_queries_planned   | bigint                   |           |          | 
+ parallel_queries_launched  | bigint                   |           |          | 
  stats_since                | timestamp with time zone |           |          | 
  minmax_stats_since         | timestamp with time zone |           |          | 
 
diff --git a/contrib/pg_stat_statements/expected/parallel.out b/contrib/pg_stat_statements/expected/parallel.out
index 8af3bd2c91..c9b1a1e339 100644
--- a/contrib/pg_stat_statements/expected/parallel.out
+++ b/contrib/pg_stat_statements/expected/parallel.out
@@ -22,13 +22,15 @@ SELECT count(*) FROM pgss_parallel_tab;
 
 SELECT query,
   parallel_workers_to_launch > 0 AS has_workers_to_launch,
-  parallel_workers_launched > 0 AS has_workers_launched
+  parallel_workers_launched > 0 AS has_workers_launched,
+  parallel_queries_planned > 0 AS has_queries_planned,
+  parallel_queries_launched > 0 AS has_queries_launched
   FROM pg_stat_statements
   WHERE query ~ 'SELECT count'
   ORDER BY query COLLATE "C";
-                 query                  | has_workers_to_launch | has_workers_launched 
-----------------------------------------+-----------------------+----------------------
- SELECT count(*) FROM pgss_parallel_tab | t                     | t
+                 query                  | has_workers_to_launch | has_workers_launched | has_queries_planned | has_queries_launched 
+----------------------------------------+-----------------------+----------------------+---------------------+----------------------
+ SELECT count(*) FROM pgss_parallel_tab | t                     | t                    | t                   | t
 (1 row)
 
 DROP TABLE pgss_parallel_tab;
diff --git a/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
index 80e6be2544..3a3964a998 100644
--- a/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
+++ b/contrib/pg_stat_statements/pg_stat_statements--1.11--1.12.sql
@@ -62,6 +62,8 @@ CREATE FUNCTION pg_stat_statements(IN showtext boolean,
     OUT jit_deform_time float8,
     OUT parallel_workers_to_launch int8,
     OUT parallel_workers_launched int8,
+    OUT parallel_queries_planned int8,
+    OUT parallel_queries_launched int8,
     OUT stats_since timestamp with time zone,
     OUT minmax_stats_since timestamp with time zone
 )
diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 773b821911..072db1281e 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -209,6 +209,10 @@ typedef struct Counters
 											 * be launched */
 	int64       parallel_workers_launched;	/* # of parallel workers actually
 											 * launched */
+	int64       parallel_queries_planned;	/* # of times query was planned
+												 * to use parallelism */
+	int64       parallel_queries_launched;	/* # of times query was executed
+												 * using parallelism */
 } Counters;
 
 /*
@@ -355,7 +359,9 @@ static void pgss_store(const char *query, uint64 queryId,
 					   const struct JitInstrumentation *jitusage,
 					   JumbleState *jstate,
 					   int parallel_workers_to_launch,
-					   int parallel_workers_launched);
+					   int parallel_workers_launched,
+					   bool parallel_queries_planned,
+					   bool parallel_queries_launched);
 static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
 										pgssVersion api_version,
 										bool showtext);
@@ -877,7 +883,9 @@ pgss_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 				   NULL,
 				   jstate,
 				   0,
-				   0);
+				   0,
+				   false,
+				   false);
 }
 
 /*
@@ -957,7 +965,9 @@ pgss_planner(Query *parse,
 				   NULL,
 				   NULL,
 				   0,
-				   0);
+				   0,
+				   false,
+				   false);
 	}
 	else
 	{
@@ -1092,7 +1102,9 @@ pgss_ExecutorEnd(QueryDesc *queryDesc)
 				   queryDesc->estate->es_jit ? &queryDesc->estate->es_jit->instr : NULL,
 				   NULL,
 				   queryDesc->estate->es_parallel_workers_to_launch,
-				   queryDesc->estate->es_parallel_workers_launched);
+				   queryDesc->estate->es_parallel_workers_launched,
+				   queryDesc->plannedstmt->parallelModeNeeded,
+				   queryDesc->estate->es_used_parallel_mode);
 	}
 
 	if (prev_ExecutorEnd)
@@ -1225,7 +1237,9 @@ pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
 				   NULL,
 				   NULL,
 				   0,
-				   0);
+				   0,
+				   false,
+				   false);
 	}
 	else
 	{
@@ -1288,7 +1302,9 @@ pgss_store(const char *query, uint64 queryId,
 		   const struct JitInstrumentation *jitusage,
 		   JumbleState *jstate,
 		   int parallel_workers_to_launch,
-		   int parallel_workers_launched)
+		   int parallel_workers_launched,
+		   bool parallel_queries_planned,
+		   bool parallel_queries_launched)
 {
 	pgssHashKey key;
 	pgssEntry  *entry;
@@ -1494,6 +1510,10 @@ pgss_store(const char *query, uint64 queryId,
 		/* parallel worker counters */
 		entry->counters.parallel_workers_to_launch += parallel_workers_to_launch;
 		entry->counters.parallel_workers_launched += parallel_workers_launched;
+		if (parallel_queries_planned)
+			entry->counters.parallel_queries_planned += 1;
+		if (parallel_queries_launched)
+			entry->counters.parallel_queries_launched += 1;
 
 		SpinLockRelease(&entry->mutex);
 	}
@@ -1561,8 +1581,8 @@ pg_stat_statements_reset(PG_FUNCTION_ARGS)
 #define PG_STAT_STATEMENTS_COLS_V1_9	33
 #define PG_STAT_STATEMENTS_COLS_V1_10	43
 #define PG_STAT_STATEMENTS_COLS_V1_11	49
-#define PG_STAT_STATEMENTS_COLS_V1_12	51
-#define PG_STAT_STATEMENTS_COLS			51	/* maximum of above */
+#define PG_STAT_STATEMENTS_COLS_V1_12	53
+#define PG_STAT_STATEMENTS_COLS			53	/* maximum of above */
 
 /*
  * Retrieve statement statistics.
@@ -1974,6 +1994,8 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 		{
 			values[i++] = Int64GetDatumFast(tmp.parallel_workers_to_launch);
 			values[i++] = Int64GetDatumFast(tmp.parallel_workers_launched);
+			values[i++] = Int64GetDatumFast(tmp.parallel_queries_planned);
+			values[i++] = Int64GetDatumFast(tmp.parallel_queries_launched);
 		}
 		if (api_version >= PGSS_V1_11)
 		{
diff --git a/contrib/pg_stat_statements/sql/parallel.sql b/contrib/pg_stat_statements/sql/parallel.sql
index 4ce1573d13..74a5bb5195 100644
--- a/contrib/pg_stat_statements/sql/parallel.sql
+++ b/contrib/pg_stat_statements/sql/parallel.sql
@@ -18,7 +18,9 @@ SELECT count(*) FROM pgss_parallel_tab;
 
 SELECT query,
   parallel_workers_to_launch > 0 AS has_workers_to_launch,
-  parallel_workers_launched > 0 AS has_workers_launched
+  parallel_workers_launched > 0 AS has_workers_launched,
+  parallel_queries_planned > 0 AS has_queries_planned,
+  parallel_queries_launched > 0 AS has_queries_launched
   FROM pg_stat_statements
   WHERE query ~ 'SELECT count'
   ORDER BY query COLLATE "C";
-- 
2.45.2