QUERY PLAN
GroupAggregate (cost=159.12..159.24 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=159.12..159.14 rows=8 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..159.00 rows=8 width=4)
Filter: ((status = 1) AND (parent_id = ANY ('{1600,1598,1592,1591,1583,1537,1536,1535}'::integer[])))