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Too much IO [message #260493] Mon, 20 August 2007 02:46 Go to next message
marrec
Messages: 35
Registered: May 2005
Location: Mühlheim, Germany
Member
Hello,

here my Problem:

Laptop
Windows XP SP2
1GB RAM
Promise Fast Track IDE RAID Controller (2HDD 80GB - RAID 1)
Oracle 10gR2

I exported a Database from Oracle 9i and imported it in my new Database, without Problems.
I run dbms_stats for all used Schmemas and for the Dictionary.

As soon as I open the Database, Oracle performs a lot of (too much) IO. The Application running on the Database can not be used within the next 1-2 hours, because it's just too slow. An easy SQL Statement needs three minutes and more. After one or two hours the Database is "ready" and the same statements doesn't need one second to finish.
With FileMon, we see that oracle.exe reads from and writes to the Hard Disk.
Does anyone know what exactly Oracle is doing here? Why is Oracle producing so much IO?
I set up lots of Databases on 9i the same way i did it here, the all run fine.

I appreciate any help.

Greet Marc

Re: Too much IO [message #260505 is a reply to message #260493] Mon, 20 August 2007 03:18 Go to previous messageGo to next message
rleishman
Messages: 3724
Registered: October 2005
Location: Melbourne, Australia
Senior Member
1Gb is pretty skimpy for Oracle 10g. I'd check that first.

A server database is never "idle"; there is always stuff running in the background listening, monitoring and waiting. These procs all take up memory. If they don't all fit into the 1Gb minus whatever XP chews up, they will be paging to and from disk just to stay alive - even when you are not running anything else.

Ross Leishman
Re: Too much IO [message #260554 is a reply to message #260493] Mon, 20 August 2007 05:15 Go to previous messageGo to next message
marrec
Messages: 35
Registered: May 2005
Location: Mühlheim, Germany
Member
Hi,

thx for the help.
1GB is enough RAM, is just a single-user laptop for sales demonstrations.

But the Problem is solved.
There was a Big Job running always after startup, which took all the performance.
The Start-Time for the Job should have been everyday at 11pm, but it started always after Database Startup.

Do you know why? I don't think, that Oracle 9i had the same behaviour.

thx
Marc
Re: Too much IO [message #261700 is a reply to message #260554] Thu, 23 August 2007 06:42 Go to previous message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
The job will have been running at startup because the jobq process will have started, and scanned the job queue for un-broken jobs with a next execution time before the current time.
This has been standard functionality since at least 8i.
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