本文主要是介绍flashback database实验（使用lgmnr找出还原时间点），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
开启闪回： http://blog.csdn.net/rlhua/article/details/11934831
过程：激活日志--删数据--查日志--logmnr--关库--不用转储--mount--flashback数据库（时间减一秒）--read only
开库看正确与否--关库--mount--开库resetlogs
DDL语句的恢复：类似不完全恢复，可以恢复到某个时间点，依赖flashback log.
logmnr依赖的是redo和归档。
flashback database一般用于ddl操作，
dml用flashback query或flashback table。因为他们读undo块
ddl语句不生成undo块
闪回数据库有限制：比如解决不了media recovery等（硬盘坏了等）。还是备份最重要。
1、使用logmnr来记录时间点，首先必须设置有一下参数
show parameter utl; logmnr需要的路径
sys@TEST0910> show parameter utl
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
create_stored_outlines string
utl_file_dir string /u01/app/oracle/utl
使用 flashback database首先设置两个参数：
db_recovery_file_dest string /u01/app/oracle/fast_recovery_area
db_recovery_file_dest_size big integer 4122M
sys@TEST0910> show parameter recovery
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest string /u01/app/oracle/fast_recovery_
area
db_recovery_file_dest_size big integer 4122M
而且需要alter database flashback on
ys@TEST0910> select name,flashback_on from v$database;
NAME FLASHBACK_ON
-------------------------------------------------- ------------------
TEST0910 YES
1 row selected.
2、查询原数据
sys@TEST0910> select count(*) from scott.test12;
COUNT(*)
----------
14
1 row selected.
3.激活logmnr，注意，必须有此步骤，不然logmnr出不来数据
sys@TEST0910> ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
Database altered.
4、误操作DDL操作
sys@TEST0910> truncate table scott.test12;
Table truncated.
sys@TEST0910> select count(*) from scott.test12;
COUNT(*)
----------
0
1 row selected.
5、查询当前日志组和归档日志
sys@TEST0910> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------------- ------------ -------------------
1 1 7 52428800 512 1 YES INACTIVE 1977009 2013-09-23 15:04:56 1981677 2013-09-23 15:05:11
2 1 8 52428800 512 1 YES ACTIVE 1981677 2013-09-23 15:05:11 1985831 2013-09-23 15:05:41
3 1 9 52428800 512 1 NO CURRENT 1985831 2013-09-23 15:05:41 2.8147E+14
3 rows selected.
sys@TEST0910> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- ------- -------------------------------------------------- ---
2 ONLINE /u01/app/oracle/oradata/test0910/redo02.log NO
1 ONLINE /u01/app/oracle/oradata/test0910/redo01.log NO
3 ONLINE /u01/app/oracle/oradata/test0910/redo03.log NO
3 rows selected.
sys@TEST0910> select name from v$archived_log;
NAME
----------------------------------------------------------------------------------------------------
/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_6_94146rg7_.arc
/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_7_941477xf_.arc
/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_8_941485th_.arc
61 rows selected.
6、执行logmnr
EXECUTE DBMS_LOGMNR_D.BUILD('dictionary.ora', -
'/u01/app/oracle/utl', -
DBMS_LOGMNR_D.STORE_IN_FLAT_FILE);
EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
LOGFILENAME => '/u01/app/oracle/oradata/test0910/redo03.log', -
OPTIONS => DBMS_LOGMNR.NEW);
EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
LOGFILENAME => '/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_6_94146rg7_.arc', -
OPTIONS => DBMS_LOGMNR.ADDFILE);
EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
LOGFILENAME => '/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_7_941477xf_.arc', -
OPTIONS => DBMS_LOGMNR.ADDFILE);
EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
LOGFILENAME => '/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_8_941485th_.arc', -
OPTIONS => DBMS_LOGMNR.ADDFILE);
EXECUTE DBMS_LOGMNR.START_LOGMNR( -
DICTFILENAME =>'/u01/app/oracle/utl/dictionary.ora',OPTIONS => -
DBMS_LOGMNR.DDL_DICT_TRACKING);
EXECUTE DBMS_LOGMNR.END_LOGMNR;
logminer官方参考： http://docs.oracle.com/cd/E11882_01/server.112/e22490/logminer.htm#i1009063
以下为执行步骤
sys@TEST0910> EXECUTE DBMS_LOGMNR_D.BUILD('dictionary.ora', -
> '/u01/app/oracle/utl', -
> DBMS_LOGMNR_D.STORE_IN_FLAT_FILE);
LogMnr Dictionary Procedure started
LogMnr Dictionary File Opened
Procedure executed successfully - LogMnr Dictionary Created
PL/SQL procedure successfully completed.
sys@TEST0910> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
> LOGFILENAME => '/u01/app/oracle/oradata/test0910/redo03.log', -
> OPTIONS => DBMS_LOGMNR.NEW);
PL/SQL procedure successfully completed.
sys@TEST0910> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
> LOGFILENAME => '/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_8_941485th_.arc', -
> OPTIONS => DBMS_LOGMNR.ADDFILE);
PL/SQL procedure successfully completed.
sys@TEST0910> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
> LOGFILENAME => '/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_7_941477xf_.arc', -
> OPTIONS => DBMS_LOGMNR.ADDFILE);
PL/SQL procedure successfully completed.
sys@TEST0910> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( -
> LOGFILENAME => '/u01/app/oracle/fast_recovery_area/TEST0910/archivelog/2013_09_23/o1_mf_1_6_94146rg7_.arc', -
> OPTIONS => DBMS_LOGMNR.ADDFILE);
PL/SQL procedure successfully completed.
sys@TEST0910> EXECUTE DBMS_LOGMNR.START_LOGMNR( -
> DICTFILENAME =>'/u01/app/oracle/utl/dictionary.ora',OPTIONS => -
> DBMS_LOGMNR.DDL_DICT_TRACKING);
PL/SQL procedure successfully completed.
7、设置session时间格式
sys@TEST0910> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';
Session altered.
8、查询logmnr分析出的数据
sys@TEST0910> select username,scn,timestamp,sql_redo from v$logmnr_contents
2 where seg_name='TEST12';
USERNAME SCN TIMESTAMP SQL_REDO
------------------------------ ---------- ------------------- --------------------------------------------------
SYS 1989009 2013-09-23 15:09:53 truncate table scott.test12;
sys@TEST0910> EXECUTE DBMS_LOGMNR.END_LOGMNR;
PL/SQL procedure successfully completed.
8、mount状态下闪回
sys@TEST0910> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
sys@TEST0910> startup mount;
ORACLE instance started.
Total System Global Area 2505338880 bytes
Fixed Size 2230952 bytes
Variable Size 587203928 bytes
Database Buffers 1895825408 bytes
Redo Buffers 20078592 bytes
Database mounted.
sys@TEST0910> flashback database to timestamp to_timestamp('2013-09-23 15:09:52','yyyy-mm-dd hh24:mi:ss');
此处注意，时间在logmnr查询出的基础上减1秒
Flashback complete.
9、让数据库置于read only，检查数据是否正确恢复
sys@TEST0910> alter database open read only;
Database altered.
sys@TEST0910> select count(*) from scott.test12;
COUNT(*)
----------
14
1 row selected.
10、重新启动数据库，使用resetlogs打开数据库
sys@TEST0910> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
sys@TEST0910> startup mount;
ORACLE instance started.
Total System Global Area 2505338880 bytes
Fixed Size 2230952 bytes
Variable Size 587203928 bytes
Database Buffers 1895825408 bytes
Redo Buffers 20078592 bytes
Database mounted.
sys@TEST0910> alter database open
2 ;
alter database open
*
ERROR at line 1:
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
sys@TEST0910> alter database open resetlogs;
Database altered.
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