Default storage of locally managed tablespaces "created" by migration from dictionary managed tablespaces can still be altered. LMTs created by CREATE TABLESPACE EXTENT MANAGEMENT LOCAL with or without UNIFORM SIZE cannot. On 9.0.1.4, Windows 2000 SQL> create tablespace test datafile 'f:\temp\test.dbf' size 1m default storage (initial 8k next 8k maxextents 50) extent management dictionary; Tablespace created. SQL> select * from dba_tablespaces where tablespace_name = 'TEST'; TABLESPACE_NAME BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE MIN_EXTLEN STATUS CONTENTS LOGGING ------------------------------ ---------- -------------- ----------- ----------- ----------- ------------ ---------- --------- --------- --------- EXTENT_MAN ALLOCATIO PLU SEGMEN ---------- --------- --- ------ TEST 8192 16384 8192 1 50 50 0 ONLINE PERMANENT LOGGING DICTIONARY USER NO MANUAL SQL> exec dbms_space_admin.tablespace_migrate_to_local('TEST', 1) PL/SQL procedure successfully completed. SQL> select * from dba_tablespaces where tablespace_name = 'TEST'; TABLESPACE_NAME BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE MIN_EXTLEN STATUS CONTENTS LOGGING ------------------------------ ---------- -------------- ----------- ----------- ----------- ------------ ---------- --------- --------- --------- EXTENT_MAN ALLOCATIO PLU SEGMEN ---------- --------- --- ------ TEST 8192 16384 8192 1 50 50 0 ONLINE PERMANENT LOGGING LOCAL USER NO MANUAL SQL> alter tablespace test default storage (initial 32k next 32k maxextents unlimited); Tablespace altered. SQL> select * from dba_tablespaces where tablespace_name = 'TEST'; TABLESPACE_NAME BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE MIN_EXTLEN STATUS CONTENTS LOGGING ------------------------------ ---------- -------------- ----------- ----------- ----------- ------------ ---------- --------- --------- --------- EXTENT_MAN ALLOCATIO PLU SEGMEN ---------- --------- --- ------ TEST 8192 32768 32768 1 2147483645 50 0 ONLINE PERMANENT LOGGING LOCAL USER NO MANUAL SQL> drop tablespace test including contents and datafiles; Tablespace dropped. SQL> create tablespace test datafile 'f:\temp\test.dbf' size 1m extent management local; Tablespace created. SQL> select * from dba_tablespaces where tablespace_name = 'TEST'; TABLESPACE_NAME BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE MIN_EXTLEN STATUS CONTENTS LOGGING ------------------------------ ---------- -------------- ----------- ----------- ----------- ------------ ---------- --------- --------- --------- EXTENT_MAN ALLOCATIO PLU SEGMEN ---------- --------- --- ------ TEST 8192 65536 1 2147483645 65536 ONLINE PERMANENT LOGGING LOCAL SYSTEM NO MANUAL SQL> alter tablespace test default storage (initial 32k next 32k maxextents unlimited); alter tablespace test default storage (initial 32k next 32k maxextents unlimited) * ERROR at line 1: ORA-25143: default storage clause is not compatible with allocation policy SQL> I guess if we could make extent ALLOCATION_TYPE USER, we could alter the default storage of the tablespace. But the AUTOALLOCATE clause sets it to SYSTEM and UNIFORM sets it to UNIFORM. Can't get it to USER.