diff --git a/src/backend/utils/activity/pgstat_function.c b/src/backend/utils/activity/pgstat_function.c
index d47d05e3d922..eef97a29de7c 100644
--- a/src/backend/utils/activity/pgstat_function.c
+++ b/src/backend/utils/activity/pgstat_function.c
@@ -112,6 +112,7 @@ pgstat_init_function_usage(FunctionCallInfo fcinfo,
 		AcceptInvalidationMessages();
 		if (!SearchSysCacheExists1(PROCOID, ObjectIdGetDatum(fcinfo->flinfo->fn_oid)))
 		{
+			pg_usleep(10000);	/* 10ms */
 			pgstat_drop_entry(PGSTAT_KIND_FUNCTION, MyDatabaseId,
 							  fcinfo->flinfo->fn_oid);
 			ereport(ERROR, errcode(ERRCODE_UNDEFINED_FUNCTION),
diff --git a/src/backend/utils/activity/pgstat_xact.c b/src/backend/utils/activity/pgstat_xact.c
index 5e2d69e62979..70a1e302514f 100644
--- a/src/backend/utils/activity/pgstat_xact.c
+++ b/src/backend/utils/activity/pgstat_xact.c
@@ -85,6 +85,8 @@ AtEOXact_PgStat_DroppedStats(PgStat_SubXactStatus *xact_state, bool isCommit)
 			 * Transaction that dropped an object committed. Drop the stats
 			 * too.
 			 */
+			if (it->kind == PGSTAT_KIND_FUNCTION)
+				pg_usleep(500000);	/* 500ms */
 			if (!pgstat_drop_entry(it->kind, it->dboid, objid))
 				not_freed_count++;
 		}