On Sun, Jun 30, 2013 at 11:52 PM, Greg Smith <g...@2ndquadrant.com> wrote: > On 6/30/13 9:28 PM, Jon Nelson wrote: >> >> The performance of the latter (new) test sometimes seems to perform >> worse and sometimes seems to perform better (usually worse) than >> either of the other two. In all cases, posix_fallocate performs >> better, but I don't have a sufficiently old kernel to test with. > > > This updated test program looks reliable now. The numbers are very tight > when I'd expect them to be, and there's nowhere with the huge differences I > saw in the earlier test program. > > Here's results from a few sets of popular older platforms:
If you found yourself with a spare moment, could you run these again with the number of open/close cycles set high (say, 100) and the number of rewrites set to 0 and also to 1? Most of the time spent is actually spent overwriting the files so by reducing or eliminating that aspect it might be easier to get a handle on the actual performance difference. -- Jon -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
