QUERY PLAN
GroupAggregate (cost=174.49..174.76 rows=10 width=12)
Group Key: parent_id
-> Sort (cost=174.49..174.55 rows=22 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..174.00 rows=22 width=4)
Filter: (parent_id = ANY ('{1618,1617,1616,1615,1614,1613,1611,1609,1603,1600,1598,1595,1592,1591,1586,1585,1584,1583,1582,1575}'::integer[]))