That sounds very reasonable. You can check that number against the values in v$undostat as it runs. Remember, UNDO_RETENTION is not guaranteed. If the space is needed by another segment, it may be taken even if the expire time has not been reached.
Daniel Thomas Jeff wrote: > Thanks for the reply Dan. > > Would you suggest setting UNDO_RETENTION to roughly the length of time of > the longest > running job in the database? For example, in our DW, our BI analysts tell > me that their > longest batch run is about 1 hr 45 minutes. My uneducated guess is to > accordingly > set the parameter to approx 2 hours. > > -----Original Message----- > Sent: Friday, September 26, 2003 4:15 PM > To: Multiple recipients of list ORACLE-L > > That is a good place to start. You might consider adding a little if you > have many concurrent transactions or want to increase the undo_retention > to a high number. Once you are using AUM, keep a close eye on > v$undostat, though there are some known issues with it not populating > properly, keep an eye on the begin_time and end_time. However, for > estimation purposes it should work. > > Daniel Fink > > Thomas Jeff wrote: > > > I'm beginning the process of converting over to automatic > > undo management. I'm wondering as to exactly how large to > > initially build the UNDO tablespace. Make it roughly > > the same size as the sum of the current rollback > > tablespaces? Or has your experience been different, > > i.e., you've found you've generally needed more or less > > space with respect to the previous allocation for rollback > > segments (manual undo)? > > > > Thanks. > > > > -------------------------------------------- > > Jeffery D Thomas > > DBA > > Thomson Information Services > > Thomson, Inc. > > > > Email: [EMAIL PROTECTED] > > > > Indy DBA Master Documentation available at: > > http://gkmqp.tce.com/tis_dba > > -------------------------------------------- > > > > -- > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > -- > > Author: Thomas Jeff > > INET: [EMAIL PROTECTED] > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > San Diego, California -- Mailing list and web hosting services > > --------------------------------------------------------------------- > > 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.net > -- > Author: Thomas Jeff > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > 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).
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