Submitted by purple73 on Sat, 2009-08-29 20:30
During a quite evening of my last on-call bout I was alerted from our monitors that the UNDO tablespace was running out of free space. Thought of adding of a new data file and be done with it; When I checked the current allocation for this tablespace it was already at 40G - couldn't believe what I was seeing. The undo_retention was set to 7200 and max query length in v$undostat was not that high. One column that did caught my eye was the tuned_undoretention, its value was way very high.