QUERY PLAN
Sort (cost=28042.85..28048.96 rows=2444 width=18)
Sort Key: c.object_type
-> HashAggregate (cost=27880.87..27905.31 rows=2444 width=18)
Group Key: c.object_type, sub.unreadcount
-> Hash Left Join (cost=21008.34..27671.46 rows=41883 width=10)
Hash Cond: ((c.object_type)::text = (sub.object_type)::text)
-> Hash Right Join (cost=10071.77..16615.99 rows=41883 width=2)
Hash Cond: (uc.comment_id = c.id)
Filter: ((uc.remind_user_id = 1001) OR (c.created_by = 1001))
-> Seq Scan on tbl_unread_comments uc (cost=0.00..5241.15 rows=40406 width=8)
Filter: (remind_user_id = 1001)
-> Hash (cost=6935.95..6935.95 rows=180386 width=10)
-> Seq Scan on tbl_comments c (cost=0.00..6935.95 rows=180386 width=10)
Filter: is_system
-> Hash (cost=10935.98..10935.98 rows=47 width=11)
-> Subquery Scan on sub (cost=10921.15..10935.98 rows=47 width=11)
-> Finalize GroupAggregate (cost=10921.15..10935.51 rows=47 width=11)
Group Key: uc_1.object_type
-> Gather Merge (cost=10921.15..10934.81 rows=47 width=11)
Workers Planned: 1
-> Partial GroupAggregate (cost=9921.14..9929.51 rows=47 width=11)
Group Key: uc_1.object_type
-> Sort (cost=9921.14..9923.77 rows=1053 width=3)
Sort Key: uc_1.object_type
-> Nested Loop (cost=0.42..9868.28 rows=1053 width=3)
-> Parallel Seq Scan on tbl_unread_comments uc_1 (cost=0.00..3814.74 rows=1256 width=7)
Filter: ((NOT is_read) AND (remind_user_id = 1001))
-> Index Scan using tbl_comments_pkey on tbl_comments c_1 (cost=0.42..4.82 rows=1 width=4)
Index Cond: (id = uc_1.comment_id)
Filter: is_system