Recursive calls can be performed to satisfy requests for space due to :
- disks sort
- a large modification to a table that require it to extend
This is generally not a problem with locally managed tablespace where space is managed as bitmaps in the datafile headers. It can happen with dictionary-managed tablespace, where space is managed in database tables much like your own data is managed.
By default from the version 9iR2, the system tablespace is created as a locally managed tablespace and you can't create any dictionary-managed tablespace