RE: Oracle db writer taking too much CPU ?

What version of Oracle and O/S?

-----Original Message-----
From: R Bresner [mailto:wawb_at_escape.net] Sent: Monday, May 01, 2000 10:47 AM
To: Multiple recipients of list ORACLE-L Subject: Oracle db writer taking too much CPU ?

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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