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RE: Hot indexes

From: Cary Millsap <cary.millsap_at_hotsos.com>
Date: Mon, 12 Jul 2004 10:11:46 -0500
Message-ID: <002201c46822$8faf3ea0$6701a8c0@CVMLAP02>


That's what we do with our Laredo product: capture SQL from various = sources,
run EXPLAIN PLAN, store the results in a database, and then use a smart comparison tool to do reporting. It works very well.

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *

Upcoming events:
- Performance Diagnosis 101: 7/20 Cleveland, 8/10 Boston, 9/14 San = Francisco
- SQL Optimization 101: 7/26 Washington DC, 8/16 Minneapolis, 9/20 = Hartford
- Hotsos Symposium 2005: March 6-10 Dallas - Visit www.hotsos.com for schedule details...

-----Original Message-----
From: oracle-l-bounce_at_freelists.org =
[mailto:oracle-l-bounce_at_freelists.org]
On Behalf Of DENNIS WILLIAMS
Sent: Monday, July 12, 2004 7:18 AM
To: 'oracle-l_at_freelists.org'
Subject: RE: Hot indexes

When this question was asked earlier, one suggestion was to capture =3D samples
of the SQL in v$sql, then run it through EXPLAIN PLAN to find SQL =3D statements
that are using indexes in this tablespace. I don't recall the success = =3D
or
failure of this method being posted.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com=3D20
I said it "looked" clear - Riddick

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Mogens N=3DF8rgaard Sent: Sunday, July 11, 2004 11:55 PM
To: oracle-l_at_freelists.org
Subject: Re: Hot indexes

If it really is a problem (somebody complaining, devices being=3D20 overloaded, whatever), then you would need to track which = user(s)/apps=3D20
issued the LIO calls to the datablock adresses of this tablespace.

Tracking of individual LIO calls including the file number, block =3D number=3D20
and number of blocks is externalized in v$session_wait and in 10046=3D20 trace files (excluding exotic direct memory access methods and probably = =3D

some decent 3rd party tools).

So putting on 10046 level 8 trace on your whole instance will show = it,=3D20
but will require at least 42 GB of storage for the trace files and = 42=3D20
days to interpret the results afterwards :).

Mogens

solbeach_at_cox.net wrote:

> I can see that one tablespace which contains only a few
> indexes is doing many, many reads.
> How do I track back to the SQL & user(s) behind this activity?



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Received on Mon Jul 12 2004 - 10:10:57 CDT

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