闪回Flashback
1-flashback drop
依赖于tablespace recycle bin 类似WINDOW回收站 SYS@ fyl>show parameter recyclebin NAME TYPE VALUE ------------------------------------ --------------------------------- ------------------------------ recyclebin string on Flashback Drop 用于非系统表空间和本地管理的表空间的恢复 sys/system用户下的默认表空间是system表空间 不能进行闪回实验--
YALI@ fyl>create table t3 as select * from emp;
Table created.
YALI@ fyl>drop table t3;
Table dropped.
YALI@ fyl>show recyclebin;
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
T3 BIN$C27+lAxZ1xPgUKjAYwYHbg==$0 TABLE 2014-12-30:21:30:28
YALI@ fyl>select count(*) from "BIN$C27+lAxZ1xPgUKjAYwYHbg==$0";
COUNT(*)
----------
14
YALI@ fyl>create table t3 as select * from dept;
Table created.
YALI@ fyl>drop table t3;
Table dropped.
YALI@ fyl>show recyclebin
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
T3 BIN$C27+lAxa1xPgUKjAYwYHbg==$0 TABLE 2014-12-30:21:34:47
T3 BIN$C27+lAxZ1xPgUKjAYwYHbg==$0 TABLE 2014-12-30:21:30:28
YALI@ fyl>select count(*) from "BIN$C27+lAxa1xPgUKjAYwYHbg==$0";
COUNT(*)
----------
4
YALI@ fyl>select table_name from tabs;
TABLE_NAME
------------------------------------------------------------------------------------------
DEPT
EMP
BONUS
SALGRADE
T1
闪回删除的count(*)=14的表
YALI@ fyl>flashback table "BIN$C27+lAxZ1xPgUKjAYwYHbg==$0" to before drop;
Flashback complete.
YALI@ fyl>select table_name from tabs;
TABLE_NAME
------------------------------------------------------------------------------------------
DEPT
EMP
BONUS
SALGRADE
T1
T3
6 rows selected.
闪回后recclebin自动删除
YALI@ fyl>show recyclebin
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------ ------------ -------------------
T3 BIN$C27+lAxa1xPgUKjAYwYHbg==$0 TABLE 2014-12-30:21:34:47
YALI@ fyl>flashback table "BIN$C27+lAxa1xPgUKjAYwYHbg==$0" to before drop rename to t3_old;
Flashback complete.
YALI@ fyl>select table_name from tabs;
TABLE_NAME
------------------------------------------------------------------------------------------
DEPT
EMP
BONUS
SALGRADE
T1
T3
T3_OLD
7 rows selected.
YALI@ fyl>show recyclebin
YALI@ fyl>select count(*) from t3;
COUNT(*)
----------
14
YALI@ fyl>select count(*) from t3_old;
COUNT(*)
----------
42--flashback query
实验--
SYS@ fyl>select * from t1;
DEPTNO DNAME LOC
---------- ------------------------------------------ ---------------------------------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
SYS@ fyl>alter session set nls_date_format ='yyyy-mm-dd hh24:mi:ss';
Session altered.
SYS@ fyl>select sysdate from dual;
SYSDATE
-------------------
2014-12-30 21:53:22
SYS@ fyl>delete from t1;
4 rows deleted.
SYS@ fyl>commit;
Commit complete.
运用闪回查询删除的数据
SYS@ fyl>select count(*) from t1 as of timestamp
2 to_timestamp('2014-12-30 21:53:22','yyyy-mm-dd hh24:mi:ss');
DEPTNO DNAME LOC
---------- ------------------------------------------ ---------------------------------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
闪回表的语法
YALI@ fyl>flashback table t1 to timestamp to_timestamp('2014-12-30 22:05:00','yyyy-mm-dd hh24:mi:ss');
3--Flashback Database
Flashback Database架构包括recover write（RVWR）后台进程，闪回日志和闪回区
启用Flashback Database功能
1）配置闪回区 SYS@ fyl>show parameter recover NAME TYPE VALUE ------------------------------------ --------------------------------- ------------------------------ db_recovery_file_dest string db_recovery_file_dest_size big integer 0 recovery_parallelism integer 0 SYS@ fyl>alter system set db_recovery_file_dest='/oracle/flash_recover_area' scope=spfile; System altered. SYS@ fyl>alter system set db_recovery_file_dest_size=1g scope=both; System altered. 2）启用闪回功能 数据库mount下 SYS@ fyl>select name,current_scn,flashback_on from v$database; NAME CURRENT_SCN FLASHBACK_ON ---------- ----------------------- -------------------- FYL 0 NO SYS@ fyl>alter database flashback on; Database altered. SYS@ fyl>select name,current_scn,flashback_on from v$database; NAME CURRENT_SCN FLASHBACK_ON ---------- ----------------------- -------------------- FYL 0 YES 此时检查闪回区下已经出现闪回日志 [oracle@fyl flashback]$ pwd /oracle/flash_recover_area/FYL/flashback [oracle@fyl flashback]$ ls -l total 8020 -rw-r----- 1 oracle dba 8200192 Dec 30 20:44 o1_mf_bb57l963_.flb 闪回进程也出现 [oracle@fyl flashback]$ ps -ef | grep rvwr oracle 4045 1 0 20:44 ? 00:00:00 ora_rvwr_fyl oracle 4057 3840 0 20:46 pts/1 00:00:00 grep rvwr 闪回时间，此时可闪回1440min=1440/60/24=1天 SYS@ fyl>show parameter flashback NAME TYPE VALUE ------------------------------------ --------------------------------- ------------------------------ db_flashback_retention_target integer 1440实验--
查看闪回信息
SYS@ fyl>select to_char(OLDEST_FLASHBACK_TIME,'yyyy-mm-dd hh24:mi:ss') oldest_time,RETENTION_TARGET,FLASHBACK_SIZE,ESTIMATED_FLASHBACK_SIZE from v$flashback_database_log; ------v$flashback_database_logfile
OLDEST_TIME RETENTION_TARGET FLASHBACK_SIZE ESTIMATED_FLASHBACK_SIZE
--------------------------------------------------------- ---------------- -------------- ------------------------
2014-12-30 20:44:58 1440 8192000 0
SYS@ fyl>select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YYYY-MM-DDHH24:MI:SS')
---------------------------------------------------------
2014-12-30 21:00:00
SYS@ fyl>create table t1 as select * from dba_objects;
Table created.
SYS@ fyl>select count(*) from t1;
COUNT(*)
----------
65489
SYS@ fyl>select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YYYY-MM-DDHH24:MI:SS')
---------------------------------------------------------
2014-12-30 21:01:29
SYS@ fyl>truncate table t1;
Table truncated.
SYS@ fyl>select count(*) from t1;
COUNT(*)
----------
0
SYS@ fyl>select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YYYY-MM-DDHH24:MI:SS')
---------------------------------------------------------
2014-12-30 21:03:15
基于时间闪回
SYS@ fyl>shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@ fyl>startup mount
ORACLE instance started.
Database mounted.
SYS@ fyl>flashback database to timestamp to_timestamp('2014-12-30 21:01:29','yyyy-mm-dd hh24:mi:ss'); --count（*）=65489时间
Flashback complete.
SYS@ fyl>alter database open read only; ----只读打开确实闪回时间点是否正确
Database altered.
SYS@ fyl>select count(*) from t1; ---确认OK
COUNT(*)
----------
65489
SYS@ fyl>shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@ fyl>startup mount
ORACLE instance started.
Database mounted.
SYS@ fyl>flashback database to timestamp to_timestamp('2014-12-30 21:00:00 ','yyyy-mm-dd hh24:mi:ss'); ---还未建表t1时间
Flashback complete.
SYS@ fyl>alter database open read only;
Database altered.
SYS@ fyl>select count(*) from t1;
select count(*) from t1
*
ERROR at line 1:
ORA-00942: table or view does not exist
如果确定好闪回时间位置
SYS@ fyl>shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@ fyl>startup mount;
ORACLE instance started.
Database mounted.
SYS@ fyl>alter database open;
alter database open
*
ERROR at line 1:
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
SYS@ fyl>alter database open resetlogs;
Database altered.
SYS@ fyl>select count(*) from t1;
select count(*) from t1
*
ERROR at line 1:
ORA-00942: table or view does not exist 此时恢复到未建表t1 时间