QUERY PLAN
GroupAggregate (cost=57.94..58.09 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=57.94..57.97 rows=9 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..57.80 rows=9 width=4)
Filter: (parent_id = ANY ('{1658,1664,1666,1667,1668,1669,1670,1671}'::integer[]))