Re: My server is oddly very slow

adrien ducos <aducos@hbs-research.com> wrote:

[rearranged somewhat]

> The version of both databases is postgres 8.4.1

[sigh]  You really should upgrade.

http://www.postgresql.org/support/versioning

http://www.postgresql.org/docs/8.4/static/release.html

> So I checked the memory on prod during my query execution:
> vmstat

> procs -----------memory----------
>  r  b   swpd   free   buff  cache
>  0  1   1280  23320   6356 2975956

> The swap is not used but something is a bit odd: the cache is
> using 98% of the RAM

The first line in vmstat (which is all you get if you run it without
a number) is averages since the OS was booted.  That's not usually
very helpful.  What does this show?:

free -m

or run the query while watching the output from:

vmstat 1

> the copy of files on the SAN is about 3 times faster than on the
> development hard drive.

Copy time doesn't always correlate real well with database
performance.  Have you tried running bonnie++ or similar?

-Kevin