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如何使用log miner分析oracle日志

发布时间:2022-11-19 11:23:51 所属栏目:语言 来源:
导读:  日常生活中,我们经常因为操作失误丢失数据或者是更改数据,如何进行恢复呐?这篇文章就是帮助我们解决这一困扰,需要的朋友可以参考下
  
  当我们不小心误操作致使数据库数据丢失、改变时, 需要对数据库

  日常生活中,我们经常因为操作失误丢失数据或者是更改数据,如何进行恢复呐?这篇文章就是帮助我们解决这一困扰,需要的朋友可以参考下
  
  当我们不小心误操作致使数据库数据丢失、改变时, 需要对数据库对象做基于时间点的恢复,找到我们需要的数据,这个时间点不能认为精确确定,我们可以通过对oracle日志进行分析,而获得无操作的精确时间点。
  
  oracle db提供了一个分析日志包logmnr
  
  logminer 工具的使用
  
  -------对redo log 进行挖掘,找出在某个时间点所作的DDL 或DML 操作(包括:时间点、datablock scn 、sql语句)
  
  实验测试

  SQL> select name from v$archived_log;
  
  NAME
  --------------------------------------------------
  /oracle/arch1/1_2_883536782.dbf
  
  SQL>
  SQL>
  SQL> delete from scott.t1;  
  576 rows deleted.  
  SQL> alter system archive log current;  
  System altered.  
  SQL> create table scott.t6 as select * from scott.emp;  
  Table created.  
  SQL> alter system archive log current;
  System altered.
  SQL> select name from v$archived_log;
  
  NAME
  --------------------------------------------------
  /oracle/arch1/1_2_883536782.dbf
  /oracle/arch1/1_3_883536782.dbf
  /oracle/arch1/1_4_883536782.dbf
  --启动log miner添加要分析的日志
  
  
  
  
  SQL> execute dbms_logmnr.add_logfile(logfilename=>'/oracle/arch1/1_2_883536782.dbf',options=>dbms_logmnr.new);
  
  PL/SQL procedure successfully completed.
  --添加需要分析的日志

  SQL> execute dbms_logmnr.add_logfile(logfilename=>'/oracle/arch1/1_3_883536782.dbf',options=>dbms_logmnr.addfile);  
  
  PL/SQL procedure successfully completed.  
  
  SQL> execute dbms_logmnr.add_logfile(logfilename=>'/oracle/arch1/1_4_883536782.dbf',options=>dbms_logmnr.addfile)  
  
  PL/SQL procedure successfully completed.
  --执行log miner

  SQL> execute dbms_logmnr.start_logmnr(options=>dbms_logmnr.dict_from_online_catalog);  
  
  PL/SQL procedure successfully completed.
  --查询分析结果

  SQL> alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';  
  Session altered.
  SQL> select username,scn,timestamp,sql_redo from v$logmnr_contents where seg_name='T1';  
  USERNAME SCN TIMESTAMP
  ------------------------------ ---------- -------------------
  SQL_REDO
  --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  delete from "SCOTT"."T1" where "EMPNO" = '7782' and "ENAME" = 'CLARK' and "JOB" = 'MANAGER' and "MGR" = '7839' and "HIREDATE" = TO_DATE('1981-06-09 00:00:00', 'yyyy-mm-dd hh24:mi:ss') and "SAL" = '245
  0' and "COMM" IS NULL and "DEPTNO" = '10' and ROWID = 'AAAVbSAAFAAAACXABi';
  
  SYS 1494545 2015-06-28 04:24:44
  delete from "SCOTT"."T1" where "EMPNO" = '7839' and "ENAME" = 'KING' and "JOB" = 'PRESIDENT' and "MGR" IS NULL and "HIREDATE" = TO_DATE('1981-11-17 00:00:00', 'yyyy-mm-dd hh24:mi:ss') and "SAL" = '500
  0' and "COMM" IS NULL and "DEPTNO" = '10' and ROWID = 'AAAVbSAAFAAAACXABj';
  
  SYS 1494545 2015-06-28 04:24:44
  delete from "SCOTT"."T1" where "EMPNO" = '7844' and "ENAME" = 'TURNER' and "JOB" = 'SALESMAN' and "MGR" = '7698' and "HIREDATE" = TO_DATE('1981-09-08 00:00:00', 'yyyy-mm-dd hh24:mi:ss') and "SAL" = '1
  。。。。。
  --结束log miner 分析

  SQL> execute dbms_logmnr.end_logmnr;
  
  PL/SQL procedure successfully completed.
  以上就是本文的全部内容,希望大家可以喜欢。
 

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