What about the amount of data? I've seen that happen before. Jeremy -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Stephens, Chris Sent: Tuesday, April 13, 2010 11:25 AM To: joan.hsieh@xxxxxxxxx; oracle_l Subject: RE: performance question System statistics collected during different periods of database activity? -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Joan Hsieh Sent: Tuesday, April 13, 2010 9:55 AM To: oracle_l Subject: performance question Hi dear listers, I have a very strange performance issue which I couldn't figure it out. I have 2 11.2.0.1 databases with the exactly same parameters, they both on the same server. One sql statement run on both database generated 2 diff plans. So I exported the whole schema stats from the good db, imported it to the bad one. It didn't change the result. I can easily fix the performance issue on the bad db by setting optimizer_feature_enabled to 10g, but I just wondering why the 2 databases have different plans even after I imported the stats and checked the stats. Thanks, Joan -- //www.freelists.org/webpage/oracle-l CONFIDENTIALITY NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is privileged, confidential and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient or the employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by email reply. -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l