** optimizer_dynamic_sampling
From: A Joshi <ajoshi977_at_yahoo.com>
Date: Fri, 26 Jun 2009 14:20:59 -0700 (PDT)
Message-ID: <851345.68028.qm_at_web57509.mail.re1.yahoo.com>
Hi,
About optimizer_dynamic_sampling for automatic gather of statistics. The default value in 9i was 1 and before that it was 0 and on 10G it is 2. Does it look for a certain % of data to be changed in the table before gathering statistics for the table. Is it 10% for optimizer_dynamic_sampling=2. What is it for optimizer_dynamic_sampling=1. I assume that with optimizer_dynamic_sampling=0 it will never automatically gather stats. Any other thoughts on this? Recommendations or any other changes to be made with this.. Also : sample size : any issues with auto sample size or is it better to always specify a explicit sample size. Thanks
Date: Fri, 26 Jun 2009 14:20:59 -0700 (PDT)
Message-ID: <851345.68028.qm_at_web57509.mail.re1.yahoo.com>
Hi,
About optimizer_dynamic_sampling for automatic gather of statistics. The default value in 9i was 1 and before that it was 0 and on 10G it is 2. Does it look for a certain % of data to be changed in the table before gathering statistics for the table. Is it 10% for optimizer_dynamic_sampling=2. What is it for optimizer_dynamic_sampling=1. I assume that with optimizer_dynamic_sampling=0 it will never automatically gather stats. Any other thoughts on this? Recommendations or any other changes to be made with this.. Also : sample size : any issues with auto sample size or is it better to always specify a explicit sample size. Thanks
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Jun 26 2009 - 16:20:59 CDT