Trying this now. J-D
On Thu, Dec 15, 2011 at 11:35 AM, Lars <[email protected]> wrote: > Do you see the same slowdown with the default 64k block size? > > Lars <[email protected]> schrieb: > >>I'll be busy today... I'll double check my scanning related changes as soon >>as i can. >> >>Jean-Daniel Cryans <[email protected]> schrieb: >> >>>Yes and yes. >>> >>>J-D >>>On Dec 14, 2011 5:52 PM, "Matt Corgan" <[email protected]> wrote: >>> >>>> Regions are major compacted and have empty memstores, so no merging of >>>> stores when reading? >>>> >>>> >>>> 2011/12/14 Jean-Daniel Cryans <[email protected]> >>>> >>>> > Yes sorry 1.1M >>>> > >>>> > This is PE, the table is set to a block size of 4KB and block caching >>>> > is disabled. Nothing else special in there. >>>> > >>>> > J-D >>>> > >>>> > 2011/12/14 <[email protected]>: >>>> > > Thanks for the info, J-D. >>>> > > >>>> > > I guess the 1.1 below is in millions. >>>> > > >>>> > > Can you tell us more about your tables - bloom filters, etc ? >>>> > > >>>> > > >>>> > > >>>> > > 在 Dec 14, 2011，5:26 PM，Jean-Daniel Cryans <[email protected]> 写道： >>>> > > >>>> > >> Hey guys, >>>> > >> >>>> > >> I was doing some comparisons between 0.90.5 and 0.92.0, mainly >>>> > >> regarding reads. The numbers are kinda irrelevant but the differences >>>> > >> are. BTW this is on CDH3u3 with random reads. >>>> > >> >>>> > >> In 0.90.0, scanning 50M rows that are in the OS cache I go up to about >>>> > >> 1.7M rows scanned per second. >>>> > >> >>>> > >> In 0.92.0, scanning those same rows (meaning that I didn't run >>>> > >> compactions after migrating so it's picking the same data from the OS >>>> > >> cache), I scan about 1.1 rows per second. >>>> > >> >>>> > >> 0.92 is 50% slower when scanning. >>>> > >> >>>> > >> In 0.90.0 random reading 50M rows that are OS cached I can do about >>>> > >> 200k reads per second. >>>> > >> >>>> > >> In 0.92.0, again with those same rows, I can go up to 260k per second. >>>> > >> >>>> > >> 0.92 is 30% faster when random reading. >>>> > >> >>>> > >> I've been playing with that data set for a while and the numbers in >>>> > >> 0.92.0 when using HFileV1 or V2 are pretty much the same meaning that >>>> > >> something else changed or the code that's generic to both did. >>>> > >> >>>> > >> >>>> > >> I'd like to be able to associate those differences to code changes in >>>> > >> order to understand what's going on. I would really appreciate if >>>> > >> others also took some time to test it out or to think about what could >>>> > >> cause this. >>>> > >> >>>> > >> Thx, >>>> > >> >>>> > >> J-D >>>> > >>>>
