QUERY PLAN
Finalize Aggregate (cost=9249.47..9249.48 rows=1 width=8)
-> Gather (cost=9249.36..9249.47 rows=1 width=8)
Workers Planned: 1
-> Partial Aggregate (cost=8249.36..8249.37 rows=1 width=8)
-> Nested Loop (cost=0.42..8247.29 rows=829 width=0)
-> Parallel Seq Scan on tbl_unread_comments uc (cost=0.00..3246.52 rows=1023 width=4)
Filter: ((NOT is_read) AND (remind_user_id = 1001))
-> Index Scan using tbl_comments_pkey on tbl_comments c (cost=0.42..4.89 rows=1 width=4)
Index Cond: (id = uc.comment_id)
Filter: is_system