What did my MMON at point-in-time X?

From: Martin Klier <Martin.Klier@xxxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
Date: Wed, 18 Feb 2009 15:50:25 +0100

Dear list,

I have a MMON question: MMON does, referencing the docs: "Capturing
statistics value for SQL objects which have been recently modified" (among
others).

I experienced a MMON-caused wait peak lately. The machine is rather poor
for the purpose, and there have been lots of library cache latch waits as
soon as MMON started its havoc. The application freezed as long as MMON did
its business, after five minutes all stuff normalized. The v$session, the
wait interface and ASH in general pointed out to "BEGIN
stdContext.setSessionParameter(:1, :2, :3, :4, :5); END; " causing the
trouble (latch: library cache"). But that's no real useful answer, so I am
asking here:

How can I find out what MMON really did (or does)?
If it just collected stuff about our object changes done before (index
creation/rebuild, table commenting, gather_table_stats), it was okay, but I
need to be sure that we will not freeze for another 5-minute-interval again
"out of thin air".

Best regards and thanks in advance
Martin
--
Mit freundlichem Gruß


Martin Klier
------------------------------------------------------------------------------

Klug GmbH integrierte Systeme
Lindenweg 13, D-92552 Teunz
Tel.:  +49 9671/9216-245
Fax.: +49 9671/9216-112
mailto: martin.klier@xxxxxxxxxx
www.klug-is.de
------------------------------------------------------------------------------

Geschäftsführer: Johann Klug, Roman Sorgenfrei
Sitz der Gesellschaft: Teunz, USt-ID-Nr. DE175481608,
HRB Nr. 2037, Amtsgericht Amberg

--
//www.freelists.org/webpage/oracle-l

What did my MMON at point-in-time X?

Other related posts: