Re: Oracle db writer taking too much CPU ?

Sounds like you are having a time of it.

Unfortunately, there isn't enough info
here to work with.

There are *way* too many questions to ask for me to put it all in an email, maybe someone else has the time right now?

Has your DBA run bstat/estat? This would go a long way in helping to discern what the problems might be.

There are plenty of folks here that could help you and your DBA to interpret the data from it.

Does your DBA know you are asking about this on a mail list?

He might not appreciate something he percieves as an end run.

Why not mention this list to him, and see if he is aggreable to running bstat/estat and posting the results here for dissection.

Jared

On Mon, 1 May 2000, R Bresner wrote:

> Howdy all,
>
> I just started work at a leetle place which does data
> warehousing, and my current project involves a 40GB database
> with some 19.5million rows. So, I'm not surprised when simple
> operations take a long, long, (and did I mention LONG?)
> time to finish.
> But, last week there was a problem with a control file
> (did I mention I'm not a DBA, and I'm just parroting
> what I heard?) which was causing the Oracle DB writer
> process to suck up CPU wildly as it wrote many messages
> to an alert file.
> And, my simple operations took even longer than normal.
> ( Many hours longer. )
> I watched the DBA guy fix the problem, and so I could
> now be classified as one of those people who only knows half
> the story so I assume I know everything, and from what I
> know, it still is running slow. The DBA guy says that the
> slowness I'm experiencing is back to normal slowness, (did
> I mention they're bIG BIG databases?)
>
> I'd ask for some benchmark comparisons, but I don't know
> anything about the Oracle server... Let's just assume its
> a VERY good machine, since I heard it was expensive and
> relatively new.
>
> You see, last week when the DB writer was sucking up CPU wildly
> everyone panic'd and said "Something must be DONE!" This week,
> that same db writer is still sucking up CPU, and now they're
> saying, "Oh, that's normal."
> They're saying that because there are no new messages in the
> alert file.
>
> I'm asking, is that _REALLY_ normal? I kick off a simple update:
> sqlplus @my_update &
>
> and it appears in my top as taking up between 0.15% and 5.00%, while
> the dbwr has it's own CPU to itself, and is churning away at a keen
> 33%. ( 3CPUs, ya see ).
>
> I admit up front, I'm no DBA, and I don't know what I'm mumbling
> about. I just want to get out of work earlier, ya see.
>
> If it matters, we're running Oracle server 8.0.4 on some machine
> over in that room there.
>
> Any explanation would be appreciated.
> Thanks
> --
> Author: R Bresner
> INET: wawb_at_escape.net
>
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Jared Still
Certified Oracle DBA and Part Time Perl Evangelist ;-) Regence BlueCross BlueShield of Oregon Received on Mon May 01 2000 - 11:55:51 CDT