RE: What can cause boost in LIO/PIO?

[deft backpedaling]

OK, now I think it IS the SAN. The S/A handling the SAN is helping us with our backup scenario so he's reorganizing some drives on the SAN. At about the same time he started the reorg (highly drive-intensive), my aggregate PIO rate dropped from almost 10K/s to less than 2K/s. And the LIOs dropped similarly, while the event waits increased.

I'm thinking that the impact of the reorg on the SAN caused the wait events for the PIOs to grow (from 3.5K/s to 4.7K/s). This longer wait in turn caused a decrease in LIOs because the processes are too busy waiting to generate the IO requests.

This explains everything except that the lack of contention to cause the IOs to boost in the first place happened at the same time as the first run of the DBMS_JOB at 5:00 AM. Coincidence?

How's that sound?

Rich

Rich Jesse                           System/Database Administrator
[EMAIL PROTECTED]                  Quad/Tech Inc, Sussex, WI USA

> -----Original Message-----
> From: Jesse, Rich
> Sent: Friday, June 20, 2003 12:32 PM
> To: 'Freeman Robert - IL'; 'Multiple recipients of list ORACLE-L '
> Subject: RE: What can cause boost in LIO/PIO?
>
>
> Only in part. It's an hourly complete rebuild of a
> mini-warehouse table (don't ask -- not my idea). It does do
> a few index creates and accompanying analyzes of those
> indexes and their table at the end of the procedure. I think
> this accounts for the very high PIO spikes at the end of
> every DBMS_JOB cycle, but I'm still not sure how it affected
> the other queries.
>
> Thx!
> Rich
>
> Rich Jesse System/Database Administrator
> [EMAIL PROTECTED] Quad/Tech Inc, Sussex, WI USA
>
>
> > -----Original Message-----
> > From: Freeman Robert - IL [mailto:[EMAIL PROTECTED]
> > Sent: Friday, June 20, 2003 11:06 AM
> > To: Jesse, Rich; 'Multiple recipients of list ORACLE-L '
> > Subject: RE: What can cause boost in LIO/PIO?
> >
> >
> > What was this 5am job? It wasn't an analyze was it?
> >
> > RF
> >
> > -----Original Message-----
> > From: Jesse, Rich
> > To: Multiple recipients of list ORACLE-L
> > Sent: 6/20/2003 11:29 AM
> > Subject: What can cause boost in LIO/PIO?
> >
> > Hey all,
> >
> > I'm testing out the max I/O thruput of an IBM FastT900 using a dual
> > 2.4GHz
> > w/1GB RAM on Win2K server (not my choice but it's just for testing)
> > running
> > Oracle 8.1.7. For one of my tests, I created the following
> > heirarchical
> > query:
> >
> > [yadda yadda yadda]
>

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Author: Jesse, Rich
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