Oracle数据库运维常用Sql

1、查看可以收缩的数据文件，

select * from dba_free_space where file_id in (
select file_id from dba_free_space group by file_id having count(0)=1 );
select * from dba_data_files where file_id  in (
select file_id from dba_free_space group by file_id having count(0)=1 );

select a.file#,
       a.name,
       a.bytes / 1024 / 1024 CurrentMB,
       ceil(HWM * a.block_size) / 1024 / 1024 ResizeTo,
       (a.bytes - HWM * a.block_size) / 1024 / 1024 ReleaseMB,
       'alter database datafile ''' || a.name || ''' resize ' ||
       ceil(HWM * a.block_size / 1024 / 1024) || 'M;' ResizeCmd
  from v$datafile a,
       (SELECT file_id, MAX(block_id + blocks - 1) HWM
          FROM DBA_EXTENTS
         GROUP BY file_id) b
 where a.file# = b.file_id(+)
   And (a.bytes - HWM * a.block_size) / 1024 / 1024 > 100
 --   and rownum < 10