How to tell Undo Tablespace need more space
448221Aug 3 2005 — edited Aug 3 2005It seems that Oracle will not automatically shrink the size of undo datafile. Then how can we tell if the undo tablespace is having enough free space for upcoming processing?
I tried to query the DBA_FREE_SPACE view and it showed that undo tablespace was really having very little free space available - despite all transactions were committed (I shutdown and restarted the system). Anyway, I still continued with my long update and it succeeded - despite the apparent little undo tablespace.
This confuses me. What really should be the good way to monitor the free space of undo tablespace?