QUERY PLAN
GroupAggregate (cost=47.69..47.79 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=47.69..47.71 rows=6 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..47.61 rows=6 width=4)
Filter: (parent_id = ANY ('{1596,1734}'::integer[]))