diff --git a/tests/queries/0_stateless/01786_group_by_pk_many_streams.reference b/tests/queries/0_stateless/01786_group_by_pk_many_streams.reference
new file mode 100644
index 00000000000..b8809e746a5
--- /dev/null
+++ b/tests/queries/0_stateless/01786_group_by_pk_many_streams.reference
@@ -0,0 +1,11 @@
+94950
+84950
+74950
+64950
+54950
+=======
+94950
+84950
+74950
+64950
+54950
diff --git a/tests/queries/0_stateless/01786_group_by_pk_many_streams.sql b/tests/queries/0_stateless/01786_group_by_pk_many_streams.sql
new file mode 100644
index 00000000000..e555aa4d6e6
--- /dev/null
+++ b/tests/queries/0_stateless/01786_group_by_pk_many_streams.sql
@@ -0,0 +1,16 @@
+DROP TABLE IF EXISTS group_by_pk;
+
+CREATE TABLE group_by_pk (k UInt64, v UInt64)
+ENGINE = MergeTree ORDER BY k PARTITION BY v % 50;
+
+INSERT INTO group_by_pk SELECT number / 100, number FROM numbers(1000);
+
+SELECT sum(v) AS s FROM group_by_pk GROUP BY k ORDER BY s DESC LIMIT 5
+SETTINGS optimize_aggregation_in_order = 1, max_block_size = 1;
+
+SELECT '=======';
+
+SELECT sum(v) AS s FROM group_by_pk GROUP BY k ORDER BY s DESC LIMIT 5
+SETTINGS optimize_aggregation_in_order = 0, max_block_size = 1;
+
+DROP TABLE IF EXISTS group_by_pk;