How far back can a Flashback Query go?
That is a function of how much space you provide to the undo tablespace and the rate at which undo is generated in your system. If you had unlimited space for the undo tablespace and have set the undo retention to an extremely large value, you should be able to go back as far back as desired. For a system that has a high undo rate, it may be reasonable to do flashback query up to a few days back. Also, the greater the amount of undo data, the longer it takes for flashback query to execute.
