创建示例数据

create table maclean_tab1 (t1 int,t2 date default sysdate) tablespace users
partition by range(t1) 
(partition p1 values less than (10000),
partition p2 values less than (20000),
partition p3 values less than (30000),
partition p4 values less than (40000),
partition p5 values less than (50000),
partition p6 values less than (60000),
partition p7 values less than (70000),
partition p8 values less than (80000),
partition p9 values less than (90000),
partition p10 values less than (100000),
partition p11 values less than (110000),
partition p12 values less than (120000),
partition p13 values less than (130000),
partition p14 values less than (140000),
partition p15 values less than (150000),
partition p16 values less than (160000))
;

insert into maclean_tab1(t1) select rownum from dual connect by level<160000;


commit;



SQL> select count(*) from maclean_tab1;

  COUNT(*)
----------
    159999
 

exec dbms_stats.gather_table_stats(USER,'MACLEAN_TAB1');   
    

SQL> alter system flush buffer_cache;

System altered.

SQL> /

System altered.

随即采样一些块来做 坏块 约涉及到10个块的数据

set linesize 200 pagesize 1400

select dbms_rowid.rowid_block_number(rowid) blkid,
       dbms_rowid.rowid_relative_fno(rowid) rfile
  from maclean_tab1 sample(0.01)
 where rownum <= 200
 group by dbms_rowid.rowid_block_number(rowid),
          dbms_rowid.rowid_relative_fno(rowid)
 order by 1;

     BLKID      RFILE
---------- ----------
    741833          4
    741850          4
    741994          4
    742030          4
    742085          4
    742141          4
    742159          4
    742172          4
    742173          4
    742179          4
    
    
 制造坏块
 
    
    [oracle@vrh8 udump]$ rman target  /
    
    RMAN> blockrecover datafile 4 block 741833,741850,741994,742030,742085,742141,742159,742172,742173,742179 clear;

Starting blockrecover at 21-APR-13
using channel ORA_DISK_1
Finished blockrecover at 21-APR-13


SQL> select count(*) from maclean_tab1;
select count(*) from maclean_tab1
                     *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 741833)
ORA-01110: data file 4:
'/s01/oradata/G10R25/datafile/o1_mf_users_8nx5srgb_.dbf'


通过blockrecover datafile block clear 构造了一系列坏块且没有备份 ，我们通过下列脚本挽回大部分可用数据



实际操作

drop table maclean_tab_backup;

create table maclean_tab_backup 
tablespace users 
nologging compress pctfree 0 pctused 99        --可以注释掉的
 as select * from maclean_tab1 where 1=0;

drop table bad_rows;
create table bad_rows (row_id rowid,oracle_error_code varchar2(50))
tablespace users 
nologging compress pctfree 0 pctused 99        --可以注释掉的;

set serveroutput on;
set timing on;

DECLARE
  TYPE RowIDTab IS TABLE OF ROWID INDEX BY BINARY_INTEGER;
  CURSOR Crowid_info IS
    select Do.DATA_OBJECT_ID dataid,
           DE.FILE_ID        fid,
           DE.BLOCK_ID       blkid,
           DE.BLOCKS         blkcnt
      from dba_objects DO, dba_extents DE
     where DO.OBJECT_NAME = 'MACLEAN_TAB1' 
     --and DE.PARTITION_NAME='&PARTITION_NAME'          --若指定分区则取消注释
       and nvl(DO.SUBOBJECT_NAME,'-1') = nvl(DE.PARTITION_NAME,'-1')
       and DO.OBJECT_NAME = DE.SEGMENT_NAME
       and DO.owner = 'SYS'
     order by 1, 2, 3 asc;
  bad_rows   number := 0;
  errors     varchar2(500);
  error_code varchar2(500);
  myrowid    rowid;
BEGIN
  /* Maclean Liu http://www.askmaclean.com * Copy Right 2013-4-20 */ 
  execute immediate 'alter session set commit_write=''batch,nowait'' ';
  for i in Crowid_info loop
    for j in 0 .. i.blkcnt - 1 loop
      for z in 0 .. 2000 loop
        begin
          myrowid := dbms_rowid.ROWID_CREATE(1,
                                             i.dataid,
                                             i.fid,
                                             i.blkid + j,
                                             z);
          insert into maclean_tab_backup
            select /*+ ROWID(A) */
             *
              from maclean_tab1 A
             where rowid = myrowid;
        EXCEPTION
          when OTHERS then
            BEGIN
              errors     := SQLERRM;
              error_code := SQLCODE;
              if (error_code like '%1410%' or error_code like '%8103%' or  error_code like '%1578%') then
                bad_rows := bad_rows + 1;
                insert into bad_rows values (myrowid, error_code);
                commit;
              else
                raise;
              end if;
            END;
            commit;
        end;
      end loop;
    end loop;
  end loop;
  dbms_output.put_line('Total Bad Rows: ' || bad_rows);
  commit;
END;
/




Elapsed: 00:01:10.16

SQL> select count(*) from maclean_tab_backup;

  COUNT(*)
----------
    155921
    
    
 ===>损失了少量的10个块的数据 

步骤1 创建备份表

create table <new table name>
as
select *
from   <original table name>
where  1=2;

步骤2 创建bad_rows表

create table bad_rows (row_id rowid,oracle_error_code varchar2(50));

步骤3 运行下列脚本

DECLARE
  TYPE RowIDTab IS TABLE OF ROWID INDEX BY BINARY_INTEGER;
  CURSOR Crowid_info IS
    select Do.DATA_OBJECT_ID dataid,
           DE.FILE_ID        fid,
           DE.BLOCK_ID       blkid,
           DE.BLOCKS         blkcnt
      from dba_objects DO, dba_extents DE
     where DO.OBJECT_NAME = '&TABNAME' 
     --and DE.PARTITION_NAME='&PARTITION_NAME'          --若指定分区则取消注释
       and nvl(DO.SUBOBJECT_NAME,'-1') = nvl(DE.PARTITION_NAME,'-1')
       and DO.OBJECT_NAME = DE.SEGMENT_NAME
       and DO.owner = '&OWNER'
     order by 1, 2, 3 asc;
  bad_rows   number := 0;
  errors     varchar2(500);
  error_code varchar2(500);
  myrowid    rowid;
BEGIN
  /* Maclean Liu http://www.askmaclean.com * Copy Right 2013-4-20 */ 
  execute immediate 'alter session set commit_write=''batch,nowait'' ';
  for i in Crowid_info loop
    for j in 0 .. i.blkcnt - 1 loop
      for z in 0 .. 2000 loop
        begin
          myrowid := dbms_rowid.ROWID_CREATE(1,
                                             i.dataid,
                                             i.fid,
                                             i.blkid + j,
                                             z);
          insert into &backup_table
            select /*+ ROWID(A) */
             *
              from &source_table A
             where rowid = myrowid;
        EXCEPTION
          when OTHERS then
            BEGIN
              errors     := SQLERRM;
              error_code := SQLCODE;
              if (error_code like '%1410%' or error_code like '%8103%' or  error_code like '%1578%') then
                bad_rows := bad_rows + 1;
                insert into bad_rows values (myrowid, error_code);
                commit;
              else
                raise;
              end if;
            END;
            commit;
        end;
      end loop;
    end loop;
  end loop;
  dbms_output.put_line('Total Bad Rows: ' || bad_rows);
  commit;
END;
/























REM Create a new table based on the table that is producing errors with no rows:

create table <new table name>
as
select *
from   <original table name>
where  1=2;

REM Create the table to keep track of ROWIDs pointing to affected rows:

create table bad_rows (row_id rowid
                      ,oracle_error_code number);
set serveroutput on

DECLARE
  TYPE RowIDTab IS TABLE OF ROWID INDEX BY BINARY_INTEGER;

  CURSOR c1 IS select /*+ index(tab1) */ rowid
  from <original table name> tab1
  where <indexed column> is NOT NULL;

  r RowIDTab;
  rows NATURAL := 20000;
  bad_rows number := 0 ;
  errors number;
  error_code number;
  myrowid rowid;
BEGIN
  OPEN c1;
  LOOP
   FETCH c1 BULK COLLECT INTO r LIMIT rows;
   EXIT WHEN r.count=0;
   BEGIN
    FORALL i IN r.FIRST..r.LAST SAVE EXCEPTIONS
     insert into <new table name>
     select /*+ ROWID(A) */ <list of columns from table (ie col1, col2,..)>
     from <original table name> A where rowid = r(i);
   EXCEPTION
   when OTHERS then
    BEGIN
     errors := SQL%BULK_EXCEPTIONS.COUNT;
     FOR err1 IN 1..errors LOOP
      error_code := SQL%BULK_EXCEPTIONS(err1).ERROR_CODE;
      if error_code in (1410, 8103, 1578) then
       myrowid := r(SQL%BULK_EXCEPTIONS(err1).ERROR_INDEX);
       bad_rows := bad_rows + 1;
       insert into bad_rows values(myrowid, error_code);
      else
       raise;
      end if;
     END LOOP;
    END;
   END;
   commit;
  END LOOP;
  commit;
  CLOSE c1;
  dbms_output.put_line('Total Bad Rows: '||bad_rows);
END;
/


  /* Maclean Liu http://www.askmaclean.com * Copy Right 2013-4-20 */