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=0.00..19.12 rows=40 width=10) (actual time=0.060..0.290 rows=40 loops=1)
   ->  Index Scan using "Threads_IsAnnouncement_LastPostId_idx" on "Threads"  (cost=0.00..37730.25 rows=78921 width=10) (actual time=0.058..0.284 rows=40 loops=1)
         Filter: ("BoardId" = 33)
 Total runtime: 0.332 ms
(4 rows)


db=#