QUERY PLAN
GroupAggregate (cost=57.97..58.14 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=57.97..58.00 rows=12 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..57.75 rows=12 width=4)
Filter: (parent_id = ANY ('{1647,1672,1669,1668,1667,1662,1661,1580,1578,1577}'::integer[]))