On Mon, Aug 3, 2009 at 1:58 PM, Xinan Wu <[email protected]> wrote: > 6 sec isn't crazy with 0.19. If you really want to research it, have a > look at where the time is spent, creating scanner or actually doing > the scanning. I think it's the former.
You are probably right that it is the fomer. In 0.19, scanners would open a new Reader against every file in the region before scanning could start (trip to namenode, then out to each dn to read in indices, etc.). In 0.20.0, the already-open files are used. St.Ack
