unload/load

Hi, 1) I have a table in a dedicated dbspace with many chunks in the dbspace.Since there has a been a lot of activity on that table of late , I want to free up the many holes in the dbspace and force contiguity of data.I cannot do an 'alter fragment' since I do not have enough log space to prevent a long.Tx. Setting LTAPEDEV to null is ruled out since the system is online. Unload will create a file >2GB, Is there a workaround to tide over this apart from writing a program to unload the table in parts to several files and loading them in one after the other. 2)In this case the table does not have any referential constraints , what if the table has associated referential constraints , do all the associated tables need to be touched ? Does 'set constraints deferred' help ? How would it help if I unload to several files and reload them ? TIA, Sathish Sadagopan