Flashback and UNDO
770097Jun 24 2010 — edited Jun 24 2010Recently I was going through the Flashback features, the one which I am really interested in knowing about is the Flashback table. I want to understand how is UNDO really related to this. According to the Oracle documentation "Flashback table relies on the undo data to recover the tables.The Automatic Undo Management feature allows you to specify how long they wish to retain the undo data using UNDO_RETENTION parameter" My question is, I have databases which are on 10g and 11g. The Undo tablespace sizing ranges from min of 10G-40G with UNDO_RETENTION parameter set to 900secs. Its really stupid that only Flashback database uses flb's and not any other......
1) In order to utilize this feature, how much should my undo retention be?
2) If I increase the value there might be a chance of getting "Snapshot too old error"
3) Can I really rely on this feature for any recovery like I do for Flashback database.
Any inputs will be greatly appreciated.