Re: Data Dictionary Hit Ratio - myth or fact?

From: Anjo Kolk <>
Date: Wed, 19 Mar 2008 00:41:48 +0100
Message-ID: <>

Yepp (pun intended),

I have lost years of my life fighting this stuff. In a way it is kind of dissappointing to see that it is still going on.

For this customer, let me make a prediction: 1) The data dictionary cache hit ratio is responsible for all their problems 2) They will spend a considerable amount of time and effort (and money) on this
3) They will probably in the end just increase some memory parameters and the hit ratio will go up
4) They will feel very good about it
5) Performance hasn't hasn't changed a bit

Hmm, I should do a white paper this. Yepp, I will


Op 3/18/08 10:12 AM, Tony Sequeira <> schreef:

> I help support a Database running on MS Windows Server 2003
> SP1.
> Someone has some old performance scripts that displays the data
> dictionary hit ratio amongst others. This comes in in the mid to high
> 80s. The BCHR on this system is high 90s.
> I have received a request to sort this out.
> Quote
> Data Dictionary Hit Ratio should be > 90% Check Oracle Memory
> assignment.
> End
> I am aware of the BCHR and the arguments against using it, but I cannot
> find anything specific on the DDHR. I'm thinking of sending them a link
> to Kolk's YAPP Method.
> Any pointers?
> Of course, they may be right, and this may need addressing.

Received on Tue Mar 18 2008 - 18:41:48 CDT

Original text of this message