QUERY PLAN
GroupAggregate (cost=76.52..76.85 rows=16 width=12)
Group Key: parent_id
-> Sort (cost=76.52..76.58 rows=22 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..76.03 rows=22 width=4)
Filter: (parent_id = ANY ('{1535,1667,1822,233,81,347,346,850,796,1537,1536,1550,1664,1662,1658,1661,1660,1666,1729,1672}'::integer[]))