QUERY PLAN
GroupAggregate (cost=50.44..50.56 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=50.44..50.46 rows=8 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..50.32 rows=8 width=4)
Filter: (parent_id = ANY ('{1596,1641,1647,1671,1670}'::integer[]))