QUERY PLAN
GroupAggregate (cost=56.14..56.29 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=56.14..56.17 rows=9 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..56.00 rows=9 width=4)
Filter: (parent_id = ANY ('{1671,1670,1669,1668,1667,1666,1664,1658}'::integer[]))