QUERY PLAN
Finalize Aggregate (cost=8208.42..8208.43 rows=1 width=8)
-> Gather (cost=8208.31..8208.42 rows=1 width=8)
Workers Planned: 1
-> Partial Aggregate (cost=7208.31..7208.32 rows=1 width=8)
-> Nested Loop (cost=0.42..7207.18 rows=452 width=0)
-> Parallel Seq Scan on tbl_unread_comments uc (cost=0.00..3784.44 rows=539 width=4)
Filter: ((NOT is_read) AND (remind_user_id = 5252))
-> Index Scan using tbl_comments_pkey on tbl_comments c (cost=0.42..6.35 rows=1 width=4)
Index Cond: (id = uc.comment_id)
Filter: is_system