QUERY PLAN
GroupAggregate (cost=153.04..153.10 rows=3 width=12)
Group Key: parent_id
-> Sort (cost=153.04..153.05 rows=4 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..153.00 rows=4 width=4)
Filter: ((status = 1) AND (parent_id = ANY ('{1618,1617,1616,1615}'::integer[])))