On 01/24/2012 08:58 AM, Robert Haas wrote:
One somewhat odd thing about these numbers is that, on permanent tables, all of the patches seemed to show regressions vs. master in single-client throughput. That's a slightly difficult result to believe, though, so it's probably a testing artifact of some kind.
It looks like you may have run the ones against master first, then the ones applying various patches. The one test artifact I have to be very careful to avoid in that situation is that later files on the physical disk are slower than earlier ones. There's a >30% differences between the fastest part of a regular hard drive, the logical beginning, and its end. Multiple test runs tend to creep forward onto later sections of disk, and be biased toward the earlier run in that case. To eliminate that bias when it gets bad, I normally either a) run each test 3 times, interleaved, or b) rebuild the filesystem in between each initdb.
I'm not sure that's the problem you're running into, but it's the only one I've been hit by that matches the suspicious part of your results.
-- Greg Smith 2ndQuadrant US g...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
