Re: RAC nodes regularly freezes for about 10 seconds

Marcin Szarek wrote:
> Hi!
>
> For a few months we suffer mysterious problem with Oracle 10g RAC (more
> details on server configuration at the bottom). At regular basis (every 5
> minutes) nodes of our cluster "freeze" - during couple of seconds
> operating system for some mysterious reason does nothing - as far as we're
> concerned - in userspace. Every single userspace process stops for this
> period. After a few seconds system comes back to life and all suspended
> processes content for CPU time and other resources, which in effect leads
> to higher load.
>
> We tried many investigations, which brougt us to following conclusions:
> - when Oracle instance is stopped, freezes disappear
> - since the moment we reduced shared_servers parameter from 60 to 20
> freezes last unsignificantly shorter (about 4 seconds shorter)
> - after instance restart freezes are unnoticeable, but as times
> goes by, they are again as long as 6-9 seconds
>
> Unfortunately investigation is very hard. /var/log/messages reports
> nothing, dmesg reports nothing, Oracle alert log also has nothing to say.
>
> Have you any idea what may be misconfigured or damaged? Could you please
> suggest us some further tests?
>

One more thing I should have noted in my original reply is that you may be able to help diagnosis this by running a 10046 level 12 trace on a client application. But running shared server makes diagnosing these traces more involved.

Maybe you can set up a separate dedicated server session and get a 10046 trace during the time the problem occurs? Received on Fri Aug 18 2006 - 12:34:12 CDT