Flashback Database：
案例分析：
flashback database：利用flashback log 对整个database 做回退到过去的某个时间点（用于DDL 的误操作如drop 和 truncate），类似于RMAN的不完全恢复（media recovery incompelete）
因为flashback database是不完全恢复，在恢复到过去的时间点前应该对数据库备份！
1、查看flashback database是否开启 07:21:27 SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ NO 2、创建recovery area 07:21:33 SQL> show parameter recover NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest string /u01/app/oracle/flash_recovery _area db_recovery_file_dest_size big integer 2G recovery_parallelism integer 2 ---recovery area可以存储flashback log、archive log、rman backup等 [[email protected] ~]$ mkdir -p /disk1/recovery/prod 配置recovery area： 07:22:49 SQL> alter system set db_recovery_file_dest=‘/disk1/recovery/prod‘ scope=spfile; System altered. 在归档模式下启用flashback database： 07:25:06 SQL> alter database flashback on; Database altered. 07:25:29 SQL> select flashback_on from v$database; FLASHBACK_ON ------------------ YES 07:25:38 SQL> alter database open; Database altered. 案例1：flashback database恢复DDL误操作（基于SCN) flashback database可以用于基于时间点或SCN的数据恢复（可以通过logminer来查看DDL操作的时间点） 1)模拟环境 15:18:17 [email protected] test1 >select current_scn from v$database; CURRENT_SCN ----------- 1264788 07:26:30 SQL> select * from test; EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO ---------- ---------- --------- ---------- --------- ---------- ---------- ---------- 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30 7566 JONES MANAGER 7839 02-APR-81 2975 20 7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30 7698 BLAKE MANAGER 7839 01-MAY-81 2850 30 7782 CLARK MANAGER 7839 09-JUN-81 2450 10 7788 SCOTT ANALYST 7566 19-APR-87 3000 20 7839 KING PRESIDENT 17-NOV-81 5000 10 7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30 7876 ADAMS CLERK 7788 23-MAY-87 1100 20 7900 JAMES CLERK 7698 03-DEC-81 950 30 7902 FORD ANALYST 7566 03-DEC-81 3000 20 7934 MILLER CLERK 7782 23-JAN-82 1300 10 16 rows selected. 07:26:36 SQL> drop table test purge; Table dropped. 07:27:20 SQL> create table test as select * from emp where rownum=1; Table created. 07:27:25 SQL> select * from test; EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO ---------- ---------- --------- ---------- --------- ---------- ---------- ---------- 7369 SMITH CLERK 7902 17-DEC-80 800 20 查看flashback 日志： [[email protected] ~]$ ls /disk1/recovery/prod/PROD/flashback/ o1_mf_74q999lb_.flb 关闭数据库后，在mount状态下恢复： 07:29:22 SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. 07:29:53 SQL> startup mount ORACLE instance started. Total System Global Area 314572800 bytes Fixed Size 1219184 bytes Variable Size 71304592 bytes Database Buffers 239075328 bytes Redo Buffers 2973696 bytes Database mounted. 通过flashback database将库恢复到过去的scn： 07:30:02 SQL> flashback database to scn 1264788; Flashback complete. 将database以read only方式打开，先验证下恢复是否成功，如果不成功，再从新进入mount下恢复 07:31:29 SQL> alter database open read only; Database altered. 07:31:34 SQL> select * from scott.test; EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO ---------- ---------- --------- ---------- --------- ---------- ---------- ---------- 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30 7566 JONES MANAGER 7839 02-APR-81 2975 20 7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30 7698 BLAKE MANAGER 7839 01-MAY-81 2850 30 7782 CLARK MANAGER 7839 09-JUN-81 2450 10 7788 SCOTT ANALYST 7566 19-APR-87 3000 20 7839 KING PRESIDENT 17-NOV-81 5000 10 7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30 7876 ADAMS CLERK 7788 23-MAY-87 1100 20 7900 JAMES CLERK 7698 03-DEC-81 950 30 7902 FORD ANALYST 7566 03-DEC-81 3000 20 7934 MILLER CLERK 7782 23-JAN-82 1300 10 16 rows selected. --恢复成功，重新以resetlogs的方式open database 07:31:40 SQL> shutdown immedaite SP2-0717: illegal SHUTDOWN option 07:31:45 SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. 07:32:02 SQL> startup mount ORACLE instance started. Total System Global Area 314572800 bytes Fixed Size 1219184 bytes Variable Size 71304592 bytes Database Buffers 239075328 bytes Redo Buffers 2973696 bytes Database mounted. 07:32:10 SQL> alter database open resetlogs; Database altered. 验证： 07:32:25 SQL> select * from scott.test; EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO ---------- ---------- --------- ---------- --------- ---------- ---------- ---------- 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30 7566 JONES MANAGER 7839 02-APR-81 2975 20 7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30 7698 BLAKE MANAGER 7839 01-MAY-81 2850 30 7782 CLARK MANAGER 7839 09-JUN-81 2450 10 7788 SCOTT ANALYST 7566 19-APR-87 3000 20 7839 KING PRESIDENT 17-NOV-81 5000 10 7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30 7876 ADAMS CLERK 7788 23-MAY-87 1100 20 7900 JAMES CLERK 7698 03-DEC-81 950 30 7902 FORD ANALYST 7566 03-DEC-81 3000 20 7934 MILLER CLERK 7782 23-JAN-82 1300 10 16 rows selected. 因为flashback database是不完全恢复，在恢复到过去的时间点前应该对数据库备份！ 案例2：基于timestamp的flashback database 04:04:28 SQL> show user; USER is "SYS" 04:08:04 SQL> conn scott/tiger Connected. 04:08:13 SQL> select to_char(sysdate,‘yyyy-mm-dd hh24:mi:ss‘) from dual; TO_CHAR(SYSDATE,‘YY ------------------- 2011-03-18 04:08:42 04:09:02 SQL> conn /as sysdba Connected. 04:09:07 SQL> select current_scn from v$database; CURRENT_SCN ----------- 1437597 04:09:10 SQL> conn scott/tiger Connected. 04:09:29 SQL> select * from tab; TNAME TABTYPE CLUSTERID ------------------------------ ------- ---------- EMP TABLE DEPT TABLE BONUS TABLE SALGRADE TABLE QUEST_SL_TEMP_EXPLAIN1 TABLE EMP1 TABLE ERRLOG TABLE PART_SALES TABLE T01 TABLE DEPT1 TABLE 10 rows selected. select * from t01; ID NA ---------- -- 1 TM 04:10:07 SQL> insert into t01 values(2,‘aa‘); 1 row created. 04:10:17 SQL> insert into t01 values(3,‘bb‘); 1 row created. 04:10:26 SQL> commit; Commit complete. 04:10:30 SQL> drop table t01; Table dropped. 04:10:59 SQL> conn /as sysdba Connected. 04:11:03 SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. 04:11:28 SQL> startup mount ORACLE instance started. Total System Global Area 314572800 bytes Fixed Size 1219184 bytes Variable Size 184550800 bytes Database Buffers 125829120 bytes Redo Buffers 2973696 bytes Database mounted. 将database恢复到过去的时间点： 04:12:07 SQL> flashback database to timestamp to_timestamp(‘2011-03-18 04:10:26‘,‘yyyy-mm-dd hh24:mi:ss‘); Flashback complete. 04:13:34 SQL> alter database open; alter database open * ERROR at line 1: ORA-01589: must use RESETLOGS or NORESETLOGS option for database open 04:14:10 SQL> alter database open noresetlogs; alter database open noresetlogs * ERROR at line 1: ORA-01610: recovery using the BACKUP CONTROLFILE option must be done 04:14:18 SQL> alter database open resetlogs; Database altered. 04:15:35 SQL> select * from v$log; GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ------------------- 1 1 0 52428800 2 YES UNUSED 0 2 1 0 52428800 2 YES UNUSED 0 3 1 0 52428800 2 YES UNUSED 0 4 1 0 52428800 2 YES UNUSED 0 5 1 0 52428800 2 YES UNUSED 0 6 1 1 52428800 2 NO CURRENT 1437637 2011-03-18 04:14:27 6 rows selected. 04:15:59 SQL> conn scott/tiger Connected. 04:16:18 SQL> select * from t01; ID NA ---------- -- 1 TM 04:34:35 SQL> desc v$flashback_database_log; Name Null? Type ----------------------------------------------------------------------------------- -------- - OLDEST_FLASHBACK_SCN NUMBER OLDEST_FLASHBACK_TIME DATE RETENTION_TARGET NUMBER FLASHBACK_SIZE NUMBER ESTIMATED_FLASHBACK_SIZE NUMBER 04:34:37 SQL> select * from v$flashback_database_log; OLDEST_FLASHBACK_SCN OLDEST_FLASHBACK_TI RETENTION_TARGET FLASHBACK_SIZE TIMATED_FLASHBACK_SIZE -------------------- ------------------- ---------------- -------------- ---------------------- 1436931 2011-03-18 03:51:43 1440 8192000 115703808
---未完待续。。。
时间： 2024-08-05 17:10:20