Re: measure database contention

Jaime Casanova wrote:
> we have a some bad queries (developers are working on that), some of
> them run in 17 secs and that is the average but when analyzing logs i
> found that from time to time some of them took upto 3 mins (the same
> query that normally runs in 17secs).
>
> so my question is: how could i look for contention problems?

A good first step is to identify the bottleneck.

Frequently, but not always, this is I/O.
Do you see a lot of I/O wait? Are the disks busy?

I don't know anything about your system, but I once experienced a
similar problem with a 2.6 Linux system where things improved considerably
after changing the I/O-scheduler to "elevator=deadline".

Yours,
Laurenz Albe