Syntax options: ENABLE COMPRESSION | DISABLE COMPRESSION Changes whether the rows for the table are compressed or uncompressed when stored. Enabling compression conserves disk space, but it incurs additional CPU overhead for inserting and retrieving compressed rows. Changing the COMPRESSION clause causes the database system to read all the rows in the table and write them back to the table in the changed format. If compression is enabled and you subsequently disable it, records may become fragmented because the space allowed for the record is no longer large enough.