Stefan - It is in the Oracle Student Guide for Backup & Recovery. Here is what it says:
Deferred Transaction Rollback Deferred rollback was introduced in Oracle7.3.1. It enables a database to be opened as soon as the roll forward using the redo log files is completed. The rollback of any uncommitted transactions is done after opening the database to users. The rollback could be done in one of the following ways: * By SMON, which periodically scans all the rollback segments and rolls back aborted transactions as needed. * By user processes, whereby a user process encounters a row lock held by a dead transaction and recovers the transaction, which frees the row lock, after which the user process continues processing. Prior to Oracle8i Deferred rollback could take a long time when parallel transactions are terminated by a system crash, because rollback is predominantly a serial operation. For example, a parallel update transaction with a degree of parallelism of 6 runs for 10 minutes, but fails due to a system crash. Rolling back this transaction serially by SMON could take one hour or more. With Oracle8i Fast start parallel rollback in Oracle8i enables a SMON to use parallel query slaves to complete the rollback operation. Parallel rollback is automatically started when SMON determines that the dead transaction had generated a large number of rollback blocks. The current threshold for determining whether a transaction is large is 100 rollback blocks. -----Original Message----- Sent: Friday, August 09, 2002 2:53 AM To: Multiple recipients of list ORACLE-L Hi Dennis Thanks you. Were did you find this information ? I seem to be unable to do a correct search on the documentation (I'm on 9.2 though). Regards, Stefan Jahnke Consultant BOV Aktiengesellschaft Voice: +49 201 - 4513-298 Fax: +49 201 - 4513-149 mailto:[EMAIL PROTECTED] visit our website: http://www.bov.de subscribe to our newsletter: http://www.bov.de/presse/newsletter.asp Behalten Sie den Ueberblick - mit dem neuen BasicOverView, unserer Seminaruebersicht fuer das 2. Halbjahr 2002. Sie haben noch kein Exemplar? Schreiben Sie eine E-Mail an mailto:[EMAIL PROTECTED] oder rufen Sie uns an unter 0 18 03 / 73 64 62 73! Wie Sie wissen, koennen ueber das Internet versandte E-Mails leicht unter fremden Namen erstellt oder manipuliert werden. Aus diesem Grunde bitten wir um Verstaendnis dafuer, dass wir zu Ihrem und unserem Schutz die rechtliche Verbindlichkeit der vorstehenden Erklaerungen und Aeusserungen ausschliessen. As you are probably aware, e-mails sent via the Internet can easily be copied or manipulated by third parties. For this reason we would ask for your understanding that, for your own protection and ours, we must decline all legal responsibility for the validity of the statements and comments given above. -----Urspr�ngliche Nachricht----- Von: DENNIS WILLIAMS [mailto:[EMAIL PROTECTED]] Gesendet: Donnerstag, 8. August 2002 16:48 An: Multiple recipients of list ORACLE-L Betreff: RE: Shutdown abort Stefan Well, I finally found a good reason for studying for OCP! I would not have known this answer without being forced to study. It depends on your Oracle version. The Oracle 8i answer is: On startup, Oracle performs recovery, including rolling forward all transactions. Oracle then opens the database for production use. In the background, SMON continues to roll back transactions that were not committed when the database shut down. If a process needs a block that was involved in an uncommitted transaction, then SMON goes ahead and rolls back that transaction so the process doesn't have to wait. Dennis Williams DBA Lifetouch, Inc. [EMAIL PROTECTED] -----Original Message----- Sent: Thursday, August 08, 2002 7:58 AM To: Multiple recipients of list ORACLE-L Hi list stupid one: In case of a shutdown abort and startup, are the rollback activities discontinued after startup and the rollback segs are available again ? or not ? regards, Stefan -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Stefan Jahnke 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: Stefan Jahnke 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).
