diff --git a/src/test/regress/expected/aggregates.out b/src/test/regress/expected/aggregates.out
index d54a255e58..3de98c916d 100644
--- a/src/test/regress/expected/aggregates.out
+++ b/src/test/regress/expected/aggregates.out
@@ -1931,6 +1931,12 @@ select string_agg(v, decode('ee', 'hex')) from bytea_test_table;
 drop table bytea_test_table;
 -- Test parallel string_agg and array_agg
 create table pagg_test (x int, y int);
+select pg_sleep(3);
+ pg_sleep 
+----------
+ 
+(1 row)
+
 insert into pagg_test
 select (case x % 4 when 1 then null else x end), x % 10
 from generate_series(1,5000) x;
@@ -1967,6 +1973,12 @@ from (
 	) a1
 ) a2
 group by y;
+select pg_sleep(3);
+ pg_sleep 
+----------
+ 
+(1 row)
+
 -- Ensure results are correct.
 select * from v_pagg_test order by y;
  y | tmin | tmax | tndistinct | bmin | bmax | bndistinct | amin | amax | andistinct | aamin | aamax | aandistinct 
@@ -1983,6 +1995,12 @@ select * from v_pagg_test order by y;
  9 |   19 | 4999 |        250 | 1019 | 999  |        250 |   19 | 4999 |        250 |    19 |  4999 |         250
 (10 rows)
 
+select pg_sleep(3);
+ pg_sleep 
+----------
+ 
+(1 row)
+
 -- Ensure parallel aggregation is actually being used.
 explain (costs off) select * from v_pagg_test order by y;
                                                               QUERY PLAN                                                              
diff --git a/src/test/regress/sql/aggregates.sql b/src/test/regress/sql/aggregates.sql
index 441e01d150..25dd90ec65 100644
--- a/src/test/regress/sql/aggregates.sql
+++ b/src/test/regress/sql/aggregates.sql
@@ -750,6 +750,7 @@ drop table bytea_test_table;
 
 -- Test parallel string_agg and array_agg
 create table pagg_test (x int, y int);
+select pg_sleep(3);
 insert into pagg_test
 select (case x % 4 when 1 then null else x end), x % 10
 from generate_series(1,5000) x;
@@ -789,9 +790,11 @@ from (
 ) a2
 group by y;
 
+select pg_sleep(3);
 -- Ensure results are correct.
 select * from v_pagg_test order by y;
 
+select pg_sleep(3);
 -- Ensure parallel aggregation is actually being used.
 explain (costs off) select * from v_pagg_test order by y;