Re: Re[4]: Postgres is too slow?

From: "Alex Pilosov" <alex@pilosoft.com>

> On Fri, 22 Jun 2001, Paul wrote:

> > # time dd if=/dev/hda3 of=/dev/null bs=64k count=10000
> >  10000+0 records in
> >  10000+0 records out
> >
> >  real    3m33.731s
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >  user    0m0.020s
> >  sys     2m37.960s
>
> Whoa! Your drive is only capable of 3M/s (640M/213 sec) transfer! Your
> data set is 500K*200 bytes=100M. No surprise your queries take 30 seconds
> to run, since its exactly how much it'd take to transfer 100M of data from
> your drive.

Possibly, but my tests are saturating CPU anyway (granted only a 400MHz one)
even with the whole dataset cached.

$ vmstat 10
   procs                      memory    swap          io     system
cpu
 r  b  w   swpd   free   buff  cache  si  so    bi    bo   in    cs  us  sy
id
 0  0  0      0  29692  80908  86312   0   0     0     2   24    56   2   0
3
 1  0  0      0  27712  80908  86312   0   0     0    43  112    26  88   5
7
 1  0  0      0  27528  80908  86312   0   0     0   301  127    30  94   6
0
 1  0  0      0   4380  80952 109400   0   0     0   650  153    32  78  22
0
 1  0  0      0   2072  80972 111640   0   0     0   450  141    27  87  13
0
 2  0  0      0   3024  80244 111356   0   0     0     1  108    25  99   1
0
 0  0  0      0  30492  80244  86020   0   0     0   409  135    80  48   2
50

- Richard Huxton