QUERY PLAN
GroupAggregate (cost=51.91..52.02 rows=6 width=12)
Group Key: parent_id
-> Sort (cost=51.91..51.92 rows=7 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..51.81 rows=7 width=4)
Filter: (parent_id = ANY ('{1596,1644,1641,1631,1630,1629}'::integer[]))