QUERY PLAN
GroupAggregate (cost=154.34..154.44 rows=5 width=12)
Group Key: parent_id
-> Sort (cost=154.34..154.35 rows=7 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..154.24 rows=7 width=4)
Filter: (parent_id = ANY ('{1607,1562,1561,1560,1559,1558,1557}'::integer[]))