QUERY PLAN
GroupAggregate (cost=51.66..51.92 rows=13 width=12)
Group Key: parent_id
-> Sort (cost=51.66..51.70 rows=17 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..51.31 rows=17 width=4)
Filter: (parent_id = ANY ('{1596,1647,1735,1734,1727}'::integer[]))