RE: Hot indexes

  • From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 12 Jul 2004 10:11:46 -0500

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 *

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Francisco
- SQL Optimization 101: 7/26 Washington DC, 8/16 Minneapolis, 9/20 =
Hartford
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- Visit www.hotsos.com for schedule details...


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx =
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of DENNIS WILLIAMS
Sent: Monday, July 12, 2004 7:18 AM
To: 'oracle-l@xxxxxxxxxxxxx'
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@xxxxxxxxxxxxx=3D20
I said it "looked" clear - Riddick


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Mogens N=3DF8rgaard
Sent: Sunday, July 11, 2004 11:55 PM
To: oracle-l@xxxxxxxxxxxxx
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@xxxxxxx 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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