For rebuild operations, twice the index space is used during the rebuild, as Oracle constructs the new index from the old one. The space is released once the index is rebuilt. Roger Xu <roger_xu@xxxxxxxxxxx> wrote: 1 select INITIAL_EXTENT, 2 NEXT_EXTENT, 3 EXTENT_MANAGEMENT, 4 ALLOCATION_TYPE, 5 SEGMENT_SPACE_MANAGEMENT 6 from dba_tablespaces 7* where TABLESPACE_NAME = 'PSAPREROGI' SQL> / INITIAL_EXTENT NEXT_EXTENT EXTENT_MAN ALLOCATIO SEGMEN -------------- ----------- ---------- --------- ------ 16384 40960 DICTIONARY USER MANUAL SQL>