oracle 把datafile的size用resize方法变成最小

把datafile的size用resize方法变成最小

SQL> set verify off
column file_name format a50 word_wrapped
column smallest format 999,990 heading "Smallest|Size|Poss."
column currsize format 999,990 heading "Current|Size"
column savings  format 999,990 heading "Poss.|Savings"
break on report
compute sum of savings on report

column value new_val blksize

1)Oracle block的大小
SQL>select value from v$parameter where name = 'db_block_size';

VALUE
--------------------------------------------------------------------------------
8192

2)算出每个文件的信息

select file_name,
       ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) smallest,
       ceil( blocks*&&blksize/1024/1024) currsize,
       ceil( blocks*&&blksize/1024/1024) -
       ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) savings
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(+)
/
                                                  Smallest
                                                       Size  Current    Poss.
FILE_NAME                                             Poss.     Size  Savings
-------------------------------------------------- -------- -------- --------
/oracle/oradata/orcl/system01.dbf                       705      710        5
/oracle/product/10.2.0/db_1/dbs/tivoliorts.dbf            2      250      248
/oracle/oradata/orcl/sysaux01.dbf                       764      810       46
/oracle/oradata/orcl/users01.dbf                          2        5        3
/oracle/oradata/orcl/undotbs01.dbf                       87      100       13
/oracle/ts_cus/ts_cus.dbf                                 2      100       98
/oracle/oradata/orcl/dyx                                  1
/oracle/oradata/orcl/ddd.ora                              1
/oracle/oradata/orcl/testtb.dbf                           1

                                                   Smallest
                                                       Size  Current    Poss.
FILE_NAME                                             Poss.     Size  Savings
-------------------------------------------------- -------- -------- --------
                                                                     --------
sum                                                                       413

 

3)动态生成resizesql语句
column cmd format a75 word_wrapped

select 'alter database datafile '''||file_name||''' resize ' ||
       ceil( (nvl(hwm,1)*&&blksize)/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*&&blksize/1024/1024) -
      ceil( (nvl(hwm,1)*&&blksize)/1024/1024 ) > 0
/
SQL>
CMD
---------------------------------------------------------------------------
alter database datafile '/oracle/oradata/orcl/system01.dbf' resize 705m;
alter database datafile '/oracle/product/10.2.0/db_1/dbs/tivoliorts.dbf' resize 2m;
alter database datafile '/oracle/oradata/orcl/sysaux01.dbf' resize 764m;
alter database datafile '/oracle/oradata/orcl/users01.dbf' resize 2m;
alter database datafile '/oracle/oradata/orcl/undotbs01.dbf' resize 87m;
alter database datafile '/oracle/ts_cus/ts_cus.dbf' resize 2m;

6 rows selected.