RE: cpu on AIX

Henry,

I had a similiar situation occur recently on HPUX, Oracle 817. CPU was pegged out and users were complaining of taking over 5 minutes to quey one record (usually took 5 seconds). It was a matter of statistics not being present on certain schema. A quick analyze cleared it all up. Just an idea...

Scott Shafer
San Antonio, TX
210.581.6217

> -----Original Message-----
> From: Henry Poras [SMTP:hporas_at_etal.URI.EDU]
> Sent: Wednesday, October 09, 2002 6:35 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: cpu on AIX
>
> Dennis,
> Users are complaining, and at least this time the guilty process seems to
> be
> an import from a database out of my control. What I am trying to do is
> control how often this happens. It seems a bit strange that one moderate,
> single threaded import should drain both CPUs on the server, so I was
> trying
> to see how much could be pinned on those processes (imp and associated
> oracle shadow process)and how much was due to other use and poor
> configuration.
>
> As I mentioned, both %wio (wa on vmstat AIX) and %idle were ~0. Everything
> was split (kind of evenly 50-50 to 40-60) between %usr and %sys. Using ps
> -o
> pcpu I could pin about 30% of %CPU on the import. I am not sure if this
> includes the associated system calls (io) from this process. I don't think
> so. (I wasn't seeing my %CPU adding up to 100% earlier because I was
> leaving
> out the kernal processes. I needed a ps -k flag).
>
> Now I am seeing some other funky stuff (maybe related, maybe not. I
> haven't
> looked carefully for this before so I don't know) on the same machine. The
> import ended and the %usr %sys breakdown was still 40-60. There are two
> kproc processes (async IO???) each using 44.4%CPU. That's been unchanged
> for
> hours and the machine is not being heavily used. Also, some other
> processes
> are using 10-20%CPU which puts me up over 100% (I guess it really can give
> 120%).
>
> I'll let you know what I find.
>
> Henry
>

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