Re: Separating data, index objects

From: DA Morgan <damorgan_at_psoug.org>
Date: Sat, 16 Jul 2005 18:16:03 -0700
Message-ID: <1121562968.771987@yasure>

Jonathan Lewis wrote:
> "DA Morgan" <damorgan_at_psoug.org> wrote in message
> news:1121543830.872468_at_yasure...
>

>>Now lets simulate a large full table scan.
>>
>>SELECT dbms_flashback.get_system_change_number FROM dual;
>>
>>now wait 60 seconds
>>
>>SELECT dbms_flashback.get_system_change_number FROM dual;
>>
>>A lot of SCNs were used ... and they were doing something ...
>>somewhere.
>>-- 

>
>
> Just happened to catch the tail-end on this,
> so have no idea where the main thread has
> been going.
>
> I suspect your SCN changes are probably
> CKPT (the checkpoint process) doing its
> checkpoint advance and controlfile update
> every three seconds.

I think you are correct for some of them. But there are also all of the processes related to statistics collection for AWR, background jobs (AQ for example) all of which are busy doing work all of the time.

My suspicion is that are at least reading, and likely updating, data dictionary tables.

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)

Received on Sat Jul 16 2005 - 20:16:03 CDT