There is no event as such (at least I don't know it!). However, you can look at ML Note:149815.1 How To Use DBMS_MVIEW.EXPLAIN_REWRITE and EXPLAIN_MVIEW To Diagnose Query Rewrite Problems. Arup has an article on Oramag which also tackles this issue in the current issue. (there - I used the word "issue" twice with different meanings!!) Hth, John Kanagaraj <>< DB Soft Inc Phone: 408-970-7002 (W) Fear connects you to the Negative, but Faith connects you to the Positive! I Jn 4:18 ** The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers ** -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of amit.poddar@xxxxxxxx Sent: Friday, March 11, 2005 5:28 PM To: oracle-l@xxxxxxxxxxxxx Subject: optimizer rewriting query Hi, We can use 10053 trace to list all the optimizer calculations and decesions about the query plan. But is there any event to check whether the optimizer has rewrittent our query, and if yes then to see the rewritten query. thanks amit -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l