QUERY PLAN
GroupAggregate (cost=148.52..148.58 rows=3 width=12)
Group Key: parent_id
-> Sort (cost=148.52..148.53 rows=3 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..148.50 rows=3 width=4)
Filter: (parent_id = ANY ('{1617,1616,1615}'::integer[]))