Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
Home -> Community -> Mailing Lists -> Oracle-L -> RE: UNDO RETENTION
Paula - Oracle has added a new table in 9i to help your analysis. V$UNDOSTAT
has a column MAXQUERYLEN that lists the longest query time, and can provide
a guide. SSOLDERRCNT column counts the number of snapshot too old errors in
a time period. In theory this should assist you in deciding whether your
undo tablespace is large enough.
Dennis Williams
DBA, 40%OCP
Lifetouch, Inc.
dwilliams_at_lifetouch.com
-----Original Message-----
Sent: Thursday, December 12, 2002 3:54 PM
To: Multiple recipients of list ORACLE-L
Having had frustration with rollback segments from time to time over the years I am happy to let Oracle handle it with their recommended automatic undo management and a defined undo tablespace. However, it isn't that simple is it? I imagine that undo retention is critical and if you specify too long you might have problems with performance while too little and what you loose read-consistency - any ideas on the best way to configure this little bugger?
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: DENNIS WILLIAMS
INET: DWILLIAMS_at_LIFETOUCH.COM
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: ListGuru_at_fatcity.com (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). Received on Thu Dec 12 2002 - 16:39:02 CST