QUERY PLAN
GroupAggregate (cost=76.58..76.93 rows=17 width=12)
Group Key: parent_id
-> Sort (cost=76.58..76.64 rows=24 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..76.03 rows=24 width=4)
Filter: (parent_id = ANY ('{1535,1547,1546,1548,1543,1549,1544,1565,1596,1686,1667,1734,1830,1822,1668,1580,1578,1577,1576,1566}'::integer[]))