不完全恢复
不完全恢复的基本类型:
1)基于时间点 (until time): 使整个数据库恢复到过去的一个时间点前
2)基于scn (until change): 使整个数据库恢复到过去的某个SCN前
3)基于cancel (until cancel): 使整个数据库恢复到归档日志或当前日志的断点前
不完全恢复(Incomplete recover) 适用环境:
1)在过去的某个时间点重要的数据被破坏。
2)在做完全恢复时,丢失了归档日志或当前online redo log
3)当误删除了表空间时(有控制文件备份)
4)丢失了所有的控制文件,使用备份的控制文件恢复时 (条件满足时可以完全恢复)
传统的不完全恢复的操作步骤:
1)先通过logmnr 找到误操作的时间点
2)对现在的database做新全备
3)还原该时间点前所有的datafile
4)在mount状态下,对database做recover,恢复到误操作的时间点
5)将恢复出来的table做逻辑备份(exp)
6)再将全备还原
7)将导出的表导入database(imp)
实验 1:恢复过去某个时间点误操作的table (基于时间点的不完全恢复) 前提:有冷备份,日志,归档齐全
1)准备实验数据
SQL> select * from andy;
ID
----------
4
SQL> insert into andy values(5);
1 row created.
SQL> commit;
Commit complete.
SQL> drop table andy purge;
Table dropped.
2)查看日志,归档环境
SQL> set linesize 400
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE#
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- -------------
1 1 61 52428800 512 1 NO CURRENT 1991534
2 1 59 52428800 512 1 YES INACTIVE 1959769
3 1 60 52428800 512 1 YES INACTIVE 1966481
SQL> alter system switch logfile;
System altered.
SQL> select name from v$archived_log;
NAME
----------------------------------------------------------------------------------------------------------
/home/oracle/archivelog/ORCL/archivelog/2014_12_01/o1_mf_1_47_b7rwlclg_.arc
/home/oracle/app/flash_recovery_area/ORCL/archivelog/2014_12_01/o1_mf_1_48_b7ryjgng_.arc
/home/oracle/app/flash_recovery_area/ORCL/archivelog/2014_12_01/o1_mf_1_49_b7rykz3l_.arc
/home/oracle/app/flash_recovery_area/ORCL/archivelog/2014_12_01/o1_mf_1_50_b7ryn3fl_.arc
/home/oracle/archivelog/1_51_860522448.dbf
/home/oracle/archivelog/1_52_860522448.dbf
/home/oracle/archivelog/1_53_860522448.dbf
/home/oracle/archivelog/1_54_860522448.dbf
/home/oracle/archivelog/1_55_860522448.dbf
NAME
----------------------------------------------------------------------------------------------------------
/home/oracle/archivelog/1_56_860522448.dbf
/home/oracle/archivelog/1_57_860522448.dbf
/home/oracle/archivelog/1_58_860522448.dbf
/home/oracle/archivelog/1_59_860522448.dbf
/home/oracle/archivelog/1_60_860522448.dbf
/home/oracle/archivelog/1_61_860522448.dbf
28 rows selected.
3)logmnr日志挖掘,找出purge时间点。
--日志挖掘至少要提前开SUPPLEME,如果没开,信息会报错
SQL> select supplemental_log_data_min,supplemental_log_data_pk,supplemental_log_data_ui from v$database;
SUPPLEME SUP SUP
-------- --- ---
YES NO NO
SQL> col member for a50;
SQL> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- ------- -------------------------------------------------- ---
3 ONLINE /home/oracle/app/oradata/orcl/redo03.log NO
2 ONLINE /home/oracle/app/oradata/orcl/redo02.log NO
1 ONLINE /home/oracle/app/oradata/orcl/redo01.log NO
SQL> select group#,status from v$log;
GROUP# STATUS
---------- ----------------
1 ACTIVE
2 CURRENT
3 INACTIVE
SQL> select name from v$archived_log where name is not null order by 1;
NAME
-----------------------------------------------------------------------------------------
/home/oracle/app/flash_recovery_area/ORCL/archivelog/2014_12_01/o1_mf_1_48_b7ryjgng_.arc
/home/oracle/app/flash_recovery_area/ORCL/archivelog/2014_12_01/o1_mf_1_49_b7rykz3l_.arc
/home/oracle/app/flash_recovery_area/ORCL/archivelog/2014_12_01/o1_mf_1_50_b7ryn3fl_.arc
/home/oracle/archivelog/1_51_860522448.dbf
/home/oracle/archivelog/1_52_860522448.dbf
/home/oracle/archivelog/1_53_860522448.dbf
/home/oracle/archivelog/1_54_860522448.dbf
/home/oracle/archivelog/1_55_860522448.dbf
/home/oracle/archivelog/1_56_860522448.dbf
/home/oracle/archivelog/1_57_860522448.dbf
/home/oracle/archivelog/1_58_860522448.dbf
NAME
-----------------------------------------------------------------------------------------
/home/oracle/archivelog/1_59_860522448.dbf
/home/oracle/archivelog/1_60_860522448.dbf
/home/oracle/archivelog/1_61_860522448.dbf
/home/oracle/archivelog/ORCL/archivelog/2014_12_01/o1_mf_1_47_b7rwlclg_.arc
15 rows selected.
-- 利用redolog日志进行挖掘
SQL> EXECUTE DBMS_LOGMNR.ADD_LOGFILE(LogFileName=>‘/home/oracle/app/oradata/orcl/redo01.log‘,Options=>dbms_logmnr.new);
PL/SQL procedure successfully completed.
SQL>EXECUTE DBMS_LOGMNR.ADD_LOGFIL (LogFileName=>‘/home/oracle/app/oradata/orcl/redo02.log‘,Options=>dbms_logmnr.ADDFILE);
PL/SQL procedure successfully completed.
SQL>EXECUTE DBMS_LOGMNR.ADD_LOGFILE(LogFileName=>‘/home/oracle/app/oradata/orcl/redo03.log‘,Options=>dbms_logmnr.ADDFILE);
PL/SQL procedure successfully completed.
SQL> execute DBMS_LOGMNR.START_LOGMNR(options=>dbms_logmnr.dict_from_online_catalog);
PL/SQL procedure successfully completed.
SQL> col username for a10;
SQL> col sql_redo for a45;
SQL> select username,scn,timestamp,sql_redo from v$logmnr_contents where seg_name=‘ANDY‘ order by scn;
USERNAME SCN TIMESTAMP SQL_REDO
---------- ---------- ------------------- ---------------------------------------------
ANDY 2000934 2014-12-11 09:47:15 drop table andy purge; //找到purge时间
--利用归档进行日志挖掘
SQL> show parameter utl
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
create_stored_outlines string
utl_file_dir string
SQL> alter system set utl_file_dir=‘/home/oracle/logmnr‘ scope=spfile;
System altered.
SQL> startup force;
SQL> show parameter utl;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
create_stored_outlines string
utl_file_dir string /home/oracle/logmnr
SQL> execute dbms_logmnr_d.build(‘dict.ora‘,‘/home/oracle/logmnr‘,dbms_logmnr_d.store_in_flat_file);
PL/SQL procedure successfully completed.
SQL> execute dbms_logmnr.add_logfile(logfilename=>‘/home/oracle/archivelog/1_61_860522448.dbf‘,options=>dbms_logmnr.new);
PL/SQL procedure successfully completed.
SQL> execute dbms_logmnr.start_logmnr(dictfilename=>‘/home/oracle/logmnr/dict.ora‘,options=>dbms_logmnr.ddl_dict_tracking);
PL/SQL procedure successfully completed.
SQL> select username,scn,to_char(timestamp,‘yyyy-mm-dd hh24:mi:ss‘),sql_redo from v$logmnr_contents WHERE lower(sql_redo) like ‘drop table%‘;
USERNAME SCN TO_CHAR(TIMESTAMP,‘ SQL_REDO
------------------------------ ---------- ------------------- --------------------------------------------------
ANDY 2000934 2014-12-11 09:47:15 drop table andy purge;
SQL> execute dbms_logmnr.end_logmnr;
PL/SQL procedure successfully completed.
4)关闭数据库,删除所有dbf,准备做不完全恢复
SQL> shutdown immdiate;
[[email protected] logmnr]$ cd /home/oracle/app/oradata/orcl/
[[email protected] orcl]$ rm -rf *.dbf
5)还原所有备份的数据文件
[[email protected] orcl]$ cp /home/oracle/coldbak/*.dbf /home/oracle/app/oradata/orcl/
6)根据log miner提供的信息,做基于时间点的不完全恢复
SQL> recover database until time ‘2014-12-11 09:47:15‘;
ORA-00279: change 1968596 generated at 12/10/2014 06:26:35 needed for thread 1
ORA-00289: suggestion : /home/oracle/archivelog/1_60_860522448.dbf
ORA-00280: change 1968596 for thread 1 is in sequence #60
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
auto
ORA-00279: change 1991534 generated at 12/10/2014 07:25:45 needed for thread 1
ORA-00289: suggestion : /home/oracle/archivelog/1_61_860522448.dbf
ORA-00280: change 1991534 for thread 1 is in sequence #61
Log applied.
Media recovery complete.
说明:如果恢复过程中用到归档日志则输入 auto 。用到当前日志,则输入 filename 。
7)resetlogs方式打开数据库
SQL> alter database open resetlogs;
Database altered.
8)验证
SQL> select * from andy;
ID
----------
5
4
OK,转载请标明出处。