Undo tablespace full even with no active transaction and undo_retention 10s

Question

The 9.2.0.4 instance is AUM (auto undo management). The undo table space is 50G and is almost full.
I have set the undo_retention to 10, previously it was 10800 (3hours). I restart the database. Wait quite long time.
And search on the dba_undo_extents.
select sum(bytes/(1024*1024*1024)),status from dba_undo_extents d where d.tablespace_name='UNDOTBS2' group by status;
SUM(BYTES/(1024*1024*1024)) STATUS
.574447632 EXPIRED
45.5358887 UNEXPIRED
It is hard to explain. 10 seconds already passed, at least all the extents should be expired.
Why so many 45G is still unexpried.
Is there a bug for undo tablespace? how to fix it.
It is a rac instance, I am trouble shooting the undo tablespace issues.
The UNDOTBS2 is for node2 to use.

Answer 1

If you start the database in exclusive (one instance) mode then the database instance can have only one undo tablespace so I would not expect Oracle to do anything with the undo tablespace for the non-running instance.
Run you database as normal and generate undo. See if the status changes. If if does that would imply that Oracle does not expire undo unless the undo segments (rbs segments) are accessed. Please post back with results of what you see.
Between having batch production running on all my databases that use undo tablespaces and the fact we use uniform extent undo tabllespaces I am not in a position to try to duplicate what you are seeing.
HTH -- Mark D Powell --