Re: Postgresql 9.0.2 explain analyze very slow (10x), compared to actual query time

Στις Wednesday 12 January 2011 21:17:00 ο/η Alex Hunsaker έγραψε:
> 2011/1/12 Achilleas Mantzios <achill(at)matrix(dot)gatewaynet(dot)com>:
>
> >
> > Changed that to smth like: micros_total = micros_total + (double) micros;
> > instead of the printf to beat any compiler optimization, and still linux runs at light speed:
> > FBSD_TEST : user 0.089s, sys 1.4s
> > FBSD_DEV : user 0.183s, sys 3.8s
> > LINUX_PROD : user 0.168s, sys 0s
> > (regarding that gettimeofday is a syscall in FreeBSD, and that sys time is 0 for linux, makes me think some optimization is being done)
>
> At least on x86_64, linux will use a vsyscall (v for virtual) for
> gettimeofday which does not actually need to enter/exit the kernel.
> That probably explains a large part of the speed difference here.
>

Thanx, thats the ARCH (x86_64) of our linux system.

--
Achilleas Mantzios