RE: Do you use KEEP Buffer Pool in your production system?
From: Rajesh Rao <Rajesh.Rao_at_jpmchase.com>
Date: Fri, 26 Mar 2010 10:34:29 -0400
Date: Fri, 26 Mar 2010 10:34:29 -0400
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:email@example.com] 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? -- Kamus <kamusis_at_gmail.com<mailto:firstname.lastname@example.org>> Oracle8i & 9i Certified DBA from China Oracle ACE Visit my blog for more article: http://www.dbform.com This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. Please refer to http://www.jpmorgan.com/pages/disclosures for disclosures relating to European legal entities.Received on Fri Mar 26 2010 - 09:34:29 CDT