QUERY PLAN
GroupAggregate (cost=47.91..47.96 rows=3 width=12)
Group Key: parent_id
-> Sort (cost=47.91..47.92 rows=3 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..47.89 rows=3 width=4)
Filter: (parent_id = ANY ('{1535,1667}'::integer[]))