SMON coalesces free space (extents) into larger, contiguous extents
every 2 hours and even then, only for a short period of time.
SMON will not coalesce free space if a tablespace's default storage
parameter "pctincrease" is set to 0. With Oracle 7.3 one can manually
coalesce a tablespace using the ALTER TABLESPACE ... COALESCE;
command, until then use:
SQL> alter session set events 'immediate trace name coalesce level n';
Where 'n' is the tablespace number you get from SELECT TS#, NAME
FROM SYS.TS$;
You can get status information about this process by se