RE: Do you use KEEP Buffer Pool in your production system?

Well, its horses for courses. We do use the KEEP pool to cache our most often used indexes. Have performed tests before and after and seen decrease in disk reads/elapsed times (50 to 80ms) for our main application calls. We sized the keep pool according to the size of the objects we expect to cache there. One could argue that we might have seen the same results by increasing our default cache. But then, consider the various batch jobs that perform massive reads. That would, in turn, make a good case for creating a recycle pool :)

It's a poor man's 11g flash cache :)

http://dioncho.wordpress.com/2009/02/10/loading-index-to-keep-buffer-pool/

http://jonathanlewis.wordpress.com/2010/03/20/not-keeping/


Regards
Raj

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Powell, Mark
Sent: Friday, March 26, 2010 9:50 AM
To: oracle_l
Subject: RE: Do you use KEEP Buffer Pool in your production system?

I am of the opinion that the majority of DBA's would be better off adding the buffers allocated to the keep and recycle pool to the regular buffer cache and allowing Oracle to manage it based on demand rather than to manually have to manage the keep and recycle pools.

Assumming that the pools could all be sized correctly initially the DBA still has the problem that over time many application work loads change.  Unless constanst monitoring is employed the pools can easily get "out of tune ".

Just let Oracle manage the buffer cache unless you have an extremely important process that requires manual tuning beyond what you can get through SQL alone.


________________________________
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce@freelists.org] On Behalf Of Leyi Zhang (Kamus)
Sent: Friday, March 26, 2010 6:42 AM
To: oracle_l
Subject: Do you use KEEP Buffer Pool in your production system?
Refer to AskTom:
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1590999000346302363


Tom Kyte said:
I would not use the keep pool, the default buffer cache is almost certainly better than good enough.
The keep buffer would definitely be in the SGA, it is just another buffer cache.

What do you think? Do you use  KEEP Buffer Pool in your production system?

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Kamus <kamusis_at_gmail.com<mailto:kamusis@gmail.com>>

Oracle8i & 9i Certified DBA from China
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