Hi While alterering the table to deallocate the extents which are above the HWM, we did use the following command. alter table <tab> deallocate unused; Another DBA here feels that appending the DDL with "KEEP' keyword is more beneficial. But he could not give any solid reason for doing so. alter table <tab> deallocate unused keep 10M; Can any one tell me how these two commands are different and which is more efficient? Scanned through Metalink, but could not find the correct answer for this question. Thanks in Advance Vidya ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------