QUERY PLAN
GroupAggregate (cost=49.63..49.83 rows=10 width=12)
Group Key: parent_id
-> Sort (cost=49.63..49.66 rows=14 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..49.36 rows=14 width=4)
Filter: (parent_id = ANY ('{1596,1641,1647,1687}'::integer[]))