> > > > Recheck Cond: ((sid > 20000) AND (sid < 30000)) > > > > -> Bitmap Index Scan on pk_songs2 (cost=0.00..151.59 rows=8931 > width=0) (actual time=4.071..4.071 rows=9579 loops=1) > > > > Index Cond: ((sid > 20000) AND (sid < 30000)) > > > > Is there a way to run this query on sigle throughpass with no Recheck > Cond? > > "Recheck Cond" is somewhat misleading here.
Bitmap Index Scan has almost void "recheck" impact in case the whole bitmap fits in work_mem. That means bitmap scan degrades when the number of rows in table (not the total number of returned rows) is greater than work_mem*1024*8. 60'000 rows bitmap scan will require 60'000/8=7'500 bytes ~ 8Kbytes of memory to run without additional recheck, thus I do not believe it hurts you in this particular case Regards, Vladimir Sitnikov
