データファイルの圧縮

column NAME format a40
column CurrentMB format 999,999,999,990
column ResizeTo format 999,999,999,990
column ReleaseMB format 999,999,999,990
column ResizeCMD format A50
select a.file# FILE#,a.name 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 *block_size)>0
order by 5;