QUERY PLAN
GroupAggregate (cost=55.62..55.76 rows=7 width=12)
Group Key: parent_id
-> Sort (cost=55.62..55.65 rows=9 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..55.48 rows=9 width=4)
Filter: (parent_id = ANY ('{1668,1669,1667,1671,1670,1664,1658,1666}'::integer[]))