QUERY PLAN
GroupAggregate (cost=49.55..49.72 rows=9 width=12)
Group Key: parent_id
-> Sort (cost=49.55..49.58 rows=11 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..49.36 rows=11 width=4)
Filter: ((parent_id = ANY ('{1596,1647}'::integer[])) AND (status = 1))