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

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 Sort  (cost=24114.75..24311.36 rows=78641 width=10) (actual time=350.795..387.558 rows=78889 loops=1)
   Sort Key: "IsAnnouncement", "LastPostId"
   Sort Method:  external merge  Disk: 1688kB
   ->  Seq Scan on "Threads"  (cost=0.00..16376.06 rows=78641 width=10) (actual time=0.031..154.760 rows=78889
loops=1)
         Filter: ("BoardId" = 33)
 Total runtime: 399.372 ms
(6 rows)