pgstat-leader-pid.patch

diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 2aff739466..95738a4e34 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -735,7 +735,13 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
 				wait_event = pgstat_get_wait_event(raw_wait_event);
 
 				leader = proc->lockGroupLeader;
-				if (leader)
+
+				/*
+				 * Show the leader only for active parallel workers.  This
+				 * leaves the field as NULL for the leader of a parallel
+				 * group.
+				 */
+				if (leader && leader->pid != beentry->st_procpid)
 				{
 					values[29] = Int32GetDatum(leader->pid);
 					nulls[29] = false;
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index dc49177c78..15c598b2a5 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -687,12 +687,9 @@ postgres   27093  0.0  0.0  30096  2752 ?        Ss   11:34   0:00 postgres: ser
        <structfield>leader_pid</structfield> <type>integer</type>
       </para>
       <para>
-       Process ID of the parallel group leader if this process is or
-       has been involved in parallel query, or null. This field is set
-       when a process wants to cooperate with parallel workers, and
-       remains set as long as the process exists. For a parallel group leader,
-       this field is set to its own process ID. For a parallel worker,
-       this field is set to the process ID of the parallel group leader.
+       Process ID of the parallel group leader if this process is involved
+       in parallel query, or null.  For a parallel group leader, this field
+       is <literal>NULL</literal>.
       </para></entry>
      </row>