QUERY PLAN
Limit (cost=58.77..58.79 rows=10 width=195)
-> Sort (cost=58.74..58.90 rows=65 width=195)
Sort Key: s.created_at
-> HashAggregate (cost=56.36..57.01 rows=65 width=195)
Group Key: s.id, u.id
-> Hash Left Join (cost=9.24..56.04 rows=65 width=195)
Hash Cond: (s.head_of = u.id)
-> Seq Scan on tbl_tasks s (cost=0.00..46.62 rows=65 width=191)
Filter: ((parent_id IS NULL) AND (task_group_id = 106))
-> Hash (cost=7.44..7.44 rows=144 width=4)
-> Seq Scan on tbl_users u (cost=0.00..7.44 rows=144 width=4)