db=# explain analyze SELECT "Threads"."Id" FROM "Threads"  WHERE "Threads"."BoardId" = 33 ORDER BY "Threads"."IsAnnouncement" DESC, "Threads"."LastPostId" DESC LIMIT 40 OFFSET 0;
                                                          QUERY PLAN

------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=18861.88..18861.98 rows=40 width=10) (actual time=160.508..160.516 rows=40 loops=1)
   ->  Sort  (cost=18861.88..19058.48 rows=78641 width=10) (actual time=160.504..160.507 rows=40 loops=1)
         Sort Key: "IsAnnouncement", "LastPostId"
         Sort Method:  top-N heapsort  Memory: 18kB
         ->  Seq Scan on "Threads"  (cost=0.00..16376.06 rows=78641 width=10) (actual time=0.014..132.901 rows=78889 loops=1)
               Filter: ("BoardId" = 33)
 Total runtime: 160.562 ms
(7 rows)


db=#