QUERY PLAN
GroupAggregate (cost=45.87..45.91 rows=2 width=12)
Group Key: parent_id
-> Sort (cost=45.87..45.88 rows=2 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..45.86 rows=2 width=4)
Filter: (parent_id = ANY ('{1645,1620}'::integer[]))