QUERY PLAN
GroupAggregate (cost=173.94..174.17 rows=8 width=12)
Group Key: parent_id
-> Sort (cost=173.94..173.99 rows=20 width=4)
Sort Key: parent_id
-> Seq Scan on tbl_tasks (cost=0.00..173.51 rows=20 width=4)
Filter: (parent_id = ANY ('{1607,1600,1598,1595,1592,1591,1583,1568,1566,1564,1563,1562,1561,1560,1559,1558,1557,1549,1548,1547}'::integer[]))