QUERY PLAN
GroupAggregate (cost=54.90..55.02 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=54.90..54.92 rows=8 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..54.78 rows=8 width=4)
Filter: (parent_id = ANY ('{1671,1670,1669,1668,1667,1666,1664,1658}'::integer[]))