QUERY PLAN
Sort (cost=28052.21..28058.32 rows=2444 width=18)
Sort Key: c.object_type
-> HashAggregate (cost=27890.23..27914.67 rows=2444 width=18)
Group Key: c.object_type, sub.unreadcount
-> Hash Left Join (cost=21014.61..27680.77 rows=41892 width=10)
Hash Cond: ((c.object_type)::text = (sub.object_type)::text)
-> Hash Right Join (cost=10073.70..16620.93 rows=41892 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..5244.10 rows=40429 width=8)
Filter: (remind_user_id = 1001)
-> Hash (cost=6937.40..6937.40 rows=180424 width=10)
-> Seq Scan on tbl_comments c (cost=0.00..6937.40 rows=180424 width=10)
Filter: is_system
-> Hash (cost=10940.32..10940.32 rows=47 width=11)
-> Subquery Scan on sub (cost=10925.48..10940.32 rows=47 width=11)
-> Finalize GroupAggregate (cost=10925.48..10939.85 rows=47 width=11)
Group Key: uc_1.object_type
-> Gather Merge (cost=10925.48..10939.15 rows=47 width=11)
Workers Planned: 1
-> Partial GroupAggregate (cost=9925.47..9933.85 rows=47 width=11)
Group Key: uc_1.object_type
-> Sort (cost=9925.47..9928.11 rows=1054 width=3)
Sort Key: uc_1.object_type
-> Nested Loop (cost=0.42..9872.55 rows=1054 width=3)
-> Parallel Seq Scan on tbl_unread_comments uc_1 (cost=0.00..3816.88 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