Oracle definitely *does* generate redo and undo for DDL. The reason you can't roll back a DDL statement is that each DDL "statement" is actually a macro for a sequence of DML statements on the data dictionary; that sequence of DML statements ends in a COMMIT. You cannot roll back a committed transaction.
SQL Trace a DDL statement like DROP TABLE. You'll see 40+ recursive SQL statements on the dictionary followed by a commit. You probably could recover a DROP TABLE with log miner if you really had to, but there are better tools to help you do it. You might consider the "tablespace point-in-time recovery" feature, for example. Cary Millsap Hotsos Enterprises, Ltd. http://www.hotsos.com Upcoming events: - Hotsos Clinic, Oct 1-3 San Francisco, Oct 15-17 Dallas, Dec 9-11 Honolulu - 2003 Hotsos Symposium on Oracle� System Performance, Feb 9-12 Dallas - Next event: Miracle Database Forum, Sep 20-22 Middelfart Denmark -----Original Message----- WILLIAMS Sent: Wednesday, August 28, 2002 9:49 AM To: Multiple recipients of list ORACLE-L Alexandre - Thanks for posting the link. I read the document. It describes how to track the DDL statements. Unless I overlooked something, it doesn't say you can UNDO DDL. I think the reason was explained earlier on this post, that Oracle doesn't write any redo records. For example, in the case of a DROP TABLE statement, in order to undo that statement, Oracle would have to write the equivalent of a DELETE statement for each row. This could be enormous if the table was large, and take a long time. Then we DBAs would be clamoring for a parameter that would bypass all that. I could be wrong, which is why I respond to issues like this. Dennis Williams DBA Lifetouch, Inc. [EMAIL PROTECTED] -----Original Message----- Sent: Wednesday, August 28, 2002 6:13 AM To: Multiple recipients of list ORACLE-L For 9i: http://otn.oracle.com/docs/products/oracle9i/doc_library/901_doc/server. 901/ a90117/logminer.htm#18681 For 8i not sure. Has anyone tried DROP undo in 8i? (8i docs are very poor on LogMiner) Alexandre ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, August 28, 2002 11:48 AM Alexandre Gorbatchev, As far as i know, you cannot recover from drop using logmnr.It is internal dml to data dictionary, maybe in 9i it will work, i am not sure.But in 8i, it won't work. Regards zhu chao Eachnet DBA 86-21-32174588-667 [EMAIL PROTECTED] ======= 2002-08-28 00:13:00 ,you wrote��======= >> 1.) Can we rollback a drop statement ? >No. However, you can use Log Miner. > >Alexandre >-- >Please see the official ORACLE-L FAQ: http://www.orafaq.com >-- >Author: Alexandre Gorbatchev > INET: [EMAIL PROTECTED] > >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 >San Diego, California -- Public Internet access / Mailing Lists >-------------------------------------------------------------------- >To REMOVE yourself from this mailing list, send an E-Mail message >to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in >the message BODY, include a line containing: UNSUB ORACLE-L >(or the name of mailing list you want to be removed from). You may >also send the HELP command for other information (like subscribing). = = = = = = = = = = = = = = = = = = = = ����������������zhu chao ����������������[EMAIL PROTECTED] ��������������������2002-08-28 -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: zhu chao INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Alexandre Gorbatchev INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: DENNIS WILLIAMS INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Cary Millsap INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
