改变表空间的大小

方法 ：  如果你想把 aa.dbf 这个数据文件给缩小。
1）查看这个数据文件上的数据库对象。
2）exp  出这些数据对象
3） drop 这些数据对象。
4)   alter database datafile '/export/home/oraclle/aa.dbf' resize 1000m;
5)   imp 这些数据对象
注意这些数据库对象所在的表空间。这一点是非常重要的 。

 

select 'alter database datafile ''' ||
file_name || ''' resize ' ||
ceil( (nvl(hwm,1)*8192)/1024/1024 )
|| 'm;' cmd
from dba_data_files a,
( select file_id,
max(block_id+blocks-1) hwm
from dba_extents
group by file_id ) b
where a.file_id = b.file_id(+)
and
ceil(blocks*8192/1024/1024)-
ceil((nvl(hwm,1)*
8192)/1024/1024 ) > 0;

 

 

declare
        cursor c_dbfile is        select tablespace_name        ,file_name        ,file_id        ,bytes        from sys.dba_data_files
        where status !='INVALID'
        order by tablespace_name,file_id;

        cursor c_space(v_file_id in number) is
        select block_id,blocks
        from sys.dba_free_space
        where file_id=v_file_id
        order by block_id desc;

        blocksize number(38);
       
        filesize number(38);
       
        extsize number(38);

begin

        select value into blocksize from v$parameter where name = 'db_block_size';
       
        for c_rec1 in c_dbfile        loop
       
                filesize := c_rec1.bytes;
       
                <<outer>>
       
                        for c_rec2 in c_space(c_rec1.file_id) loop
       
                                extsize := ((c_rec2.block_id - 1)*blocksize + c_rec2.blocks*blocksize);
       
                                if extsize = filesize        then
                                        filesize := (c_rec2.block_id - 1)*blocksize;       
                                else       
                                        exit outer;
                                end if;
       
                        end loop ;
       
                        if filesize = c_rec1.bytes        then       
                                dbms_output.put_line('Tablespace: '||' '||c_rec1.tablespace_name||' Datafile: '||c_rec1.file_name);
       
                                dbms_output.put_line('Can not be resized, no free space at end of file.');
                                dbms_output.put_line('.');
                        else       
                                if filesize < 2*blocksize        then
                                        dbms_output.put_line('Tablespace: '||' '||c_rec1.tablespace_name||' Datafile: '||c_rec1.file_name);
                                        dbms_output.put_line('Can be resized uptil: '||2*blocksize||' Bytes, Actual size: '||c_rec1.bytes||' Bytes');
                                        dbms_output.put_line('.');
                                else
                                        dbms_output.put_line('Tablespace: '        ||' '||c_rec1.tablespace_name||' Datafile: '||c_rec1.file_name);
                                        dbms_output.put_line('Can be resized uptil: '||filesize        ||' Bytes, Actual size: '||c_rec1.bytes);
                                        dbms_output.put_line('.');
                                end if;
                        end if;
        end loop;

end;
/

 

 

 

1  select
  2  max((e.block_id + e.blocks) * &&db_block_size/1024/1024) as "Can Resize(M)",
  3  f.bytes/1024/1024 "Current Size(M)",
  4  sum(e.bytes/1024/1024) as "totalUsed(M)",
  5  file_name
  6  from
  7  dba_extents e,dba_data_files f
  8  where
  9  e.file_id= f.file_id
10  group by
11  file_name,f.bytes/1024/1024
12* order by 2-1

Can Resize(M) Current Size(M) totalUsed(M) FILE_NAME
------------- --------------- ------------ ----------------------------------------
            4              20            4 /data/oradata/rmanrep/drsys01.dbf
           45              50           28 /data/oradata/rmanrep/rbs01.dbf
            4              50            4 /data/oradata/rmanrep/rman8i01.dbf
            4              50            4 /data/oradata/rmanrep/rman9i01.dbf
          273             280          273 /data/oradata/rmanrep/system01.dbf
            4              20            4 /data/oradata/rmanrep/temp01.dbf
          116             512          116 /data/oradata/rmanrep/tools01.dbf
            0              45            0 /data/oradata/rmanrep/users01.dbf