Originally posted by mike2000
so if it's the case, why Oracle had LOCAL EXTENT and AUTOALLOCATE which cause fragmentation, which return to the back old day when we use dictionary extent. I guess AUTOALLOCATE is for TEMPORARY not for permenant tablespaces, but if it's designed for TEMPORARY, why can't you use DICTIONARY extent for TEMPORARY tablespaces????

thanks
Use auto allocate when you don't know the size of the objects that will be created in the tablespace. So that smaller tables can have 64k or 1M extents ( that will save space, as compared to keeping smaller tables in a 20M uniformed sized extent LMT ). You can monitor the growth of the table and estimate the size of the tables and then move them accordingly to an new LMT having uniform sized extents.

Use Uniform sized LMT for tablespaces where you know the size of the objects.