Way back in 2001 Oracle announced Oracle9i with a new feature named ‘Flashback Query’. The implication was that Flashback technology would permit one to query past data, no matter how old it was days, weeks or even months old. In fact the actuality was very different since Flashback Query relied upon the undo information contained within the database Undo-Segments.
Later releases refined what was possible. It was named ‘Total Recall’ in Oracle 11g, and now goes by the name of ‘Flashback Data Archive’. This recent blog goes into a little detail of the recent changes available in Oracle release 12c.
It is an easy read, but at the back of the mind one can’t help but think how much disk storage is required on a busy site to enable one to search back over long periods of time. The feature is useful, and is available ‘free-of-charge’ with all versions of Oracle 12c, but at what cost in terms of system resources and performance?