Locally managed tablespaces have the following advantages over dictionary-managed
tablespaces:
• Local management avoids recursive space management operations, which can
occur in dictionary-managed tablespaces if consuming or releasing space in an
extent results in another operation that consumes or releases space in a rollback
segment or data dictionary table.
• Because locally managed tablespaces do not record free space in data dictionary
tables, it reduces contention on these tables.
• Local management of extents automatically tracks adjacent free space, eliminating
the need to coalesce free extents.
• The sizes of extents that are managed locally can be determined automatically by
the system. Alternatively, all extents can have the same size in a locally managed
tablespace.
• Changes to the extent bitmaps do not generate rollback information because they
do not update tables in the data dictionary (except for special cases such as
tablespace quota information).