Re: Should we stop analyzing?

----- Original Message -----

From: Whittle Jerome Contr NCI

To: Multiple recipients of list ORACLE-L

Sent: Tuesday, December 30, 2003 6:09 PM

Subject: RE: Should we stop analyzing?

I'll see your 'analyzed every 4 hours' and raise you one. We have some tables that are analyzed every time they are used! They are 'work' tables that are sometimes empty, very full, or somewhere in between. Running something when the statistics say the table is full but actually is empty takes a little longer when CBO says use indexes; however, if CBO thinks the table is empty and does a FTS when there's actually a million records, well let's just say it takes a while. Hints work sometimes; however,  analyzing these table after they are populated and letting CBO do it's job usually works best.

Two points.

First this particular database had not been analyzed for over a year when I got there and this database gets larger daily. They added indexes but it didn't make much difference. After analyzing, most things were much faster; however, the 'work' tables started acting up depending on their state when analyzed. We now analyze twice a month.

Second when it comes to these 'work' tables, I wasn't there and it wasn't my idea!

Jerry Whittle
ASIFICS DBA
NCI Information Systems Inc.
jerome.whittle@scott.af.mil
618-622-4145

-----Original Message-----
From:   Rachel Carmichael [SMTP:wisernet100@yahoo.com]

I have you beat.... one schema in one of our databases (9.2.0.2) is
analyzed every 4 hours. Not mine, and I *will* be talking to the DBA
about his reasoning...

however Jonathan's point may well be the reason. This is an
ever-growing database, frequent insert and updates, and sequences are
used throughout.
 Analyze is "estimate" at least.

--- "Jamadagni, Rajendra" <Rajendra.Jamadagni@espn.com> wrote:
> Mogens, if you are looking for a poster boy ...
>
> We analyze 9 production databases ... *every day*.
> Raj

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