Originally posted by Dilippatel
In 9i Transaction can not span over multilple Rollback segments.
Not true.

When the first DML operation in a transaction is executed, an undo segment is chosen. The AUM transaction-bind algorithm first attempts to bind one transaction per undo segment. If such a segment cannot be found, the system will attempt to online another undo segment in the current undo tablespace. If none is available, a new undo segment is created and brought online. If none of the above steps succeed, the 8i approach is used, i.e., find the least used undo segment.

The AUM mode supports dynamic transfer of undo space between undo segments. If an executing transaction needs more undo space, space is reused either from the current undo segment or through an extension. If none of these steps results in enough free space for the transaction, free undo space is STOLEN from other undo segments.

Thus you will see ORA-30036 only of the undo tablespace is totally out of space.