数据文件可以调整到的最小大小

-- Description  : Displays smallest size the datafiles can shrink to without a reorg.

-- Requirements : Access to the V$ and DBA views.

-- Call Syntax  : @min_datafile_size

SELECT a.tablespace_name,
       a.file_name,
       a.bytes AS current_bytes,
       a.bytes - b.resize_to AS shrink_by_bytes,
       b.resize_to AS resize_to_bytes
  FROM dba_data_files a,
       (SELECT file_id,
               MAX((block_id + blocks - 1) * &v_block_size) AS resize_to
          FROM dba_extents
         GROUP by file_id) b
 WHERE a.file_id = b.file_id
 ORDER BY a.tablespace_name, a.file_name