本帖最后由 guoyJoe 于 2013-3-26 21:15 编辑

一、Fashback Query闪回查询:Books-->APP-->Application Developer's Guide - Fundamentals-->Flashback

１、应用Flashback Query查询过去的数据

select * from t1 as of scn 44545454;

select * from t1 as of timestamp to_timestamp('2012-09-28:09:20:13','yyyy-mm-dd:hh24:mi:SS');

select * from t1 as of timestamp sysdate-5/1440;

--select to_char(sysdate,'yyyy-mm-dd:hh24:mi:ss') sys_time,to_char(scn_to_timestamp(current_scn),'yyyy-mm-dd:hh24:mi:ss') scn_to_time,timestamp_to_scn(sysdate) date_to_scn,dbms_flashback.get_system_change_number scn1,current_scn scn2 from v$database;

２、应用Flashback Query查询操作的事务

(1)使用Flashback Version Query 查询记录修改版本

select current_scn from v$database;

DML操作........

insert into t1 values(20,'gyj20');

commit;

update t1 set name='gyj200000' where id=20;

commit;

delete from t1 where id=20;

commit;

select current_scn from v$database;

SELECT ID,NAME,VERSIONS_STARTSCN STARTSCN,VERSIONS_ENDSCN ENDSCN,VERSIONS_OPERATION OPERATION,VERSIONS_XID XID

FROM T1 VERSIONS BETWEEN SCN 2942841 AND 2942947;

--VERSIONS_STARTSCN:该条记录操作时的SCN,如果为空,表示该行记录是在查询范围外创建的

--VERSIONS_ENDSCN:该条记录失效时的SCN,如果为空,说明记录在这段时间无操作，或者已经被删数,配合VERSIONS_OPERATION

--VERSIONS_OPERATION:Ｉ表示insert、D表示delete、U表示update

--VERSIONS_XID:该操作的事务ID

(2)使用Flashback Transaction Query 查询事务信息(可以做审计)

alter database add supplemental log data; //Oracle11g禁用了supplemental logging

select current_scn from v$database;

DML操作........

select current_scn from v$database;

select xid,commit_scn,commit_timestamp,operation,undo_sql

from flashback_transaction_query q where q.xid in (select

versions_xid from t1 versions between SCN  2943656 and 2943676);

SQL> DESC FLASHBACK_TRANSACTION_QUERY --能获得这个事务执行时的很多信息，包括UNDO语句

Name              Null?    Type

----------------- -------- ------------

XID                 RAW(8)　　　 --事务ID,对应Versions Query中的VERSIONS_XID

START_SCN           NUMBER       --事务开始时的SCN

START_TIMESTAMP     DATE         --事务开始时间

COMMIT_SCN          NUMBER　　　 --事务提交时的SCN,该列为空的话，说明事务为活动事务

COMMIT_TIMESTAMP    DATE　　　　 --事务提交时间

LOGON_USER          VARCHAR2(30) --操作用户

UNDO_CHANGE#        NUMBER　　　 --UNDO SCN

OPERATION           VARCHAR2(32) --执行操作，有几个值:Delete、Insert、Update、B、UNKNOWN

TABLE_NAME          VARCHAR2(256)--DML操作对象的表名

TABLE_OWNER         VARCHAR2(32) --表的属主

ROW_ID              VARCHAR2(19) --DML操作记录的行地址

UNDO_SQL            VARCHAR2(4000)--撤销该操作对应的SQL

二、Flashbackup Table闪回表:Books-->ADM-->Administrator's Guide-->flashback

1、从undo表空间恢复

select row_movement from user_tables where table_name='T1';

alter table t1 enable row movement;

select * from t1;

select current_scn from v$database;

delete from t1;

commit;

select * from t1;

select * from t as of scn 9999;

flashback table t1 to scn 9999;

flashback table t1 to timestamp sysdate-5/1440;

--create temporary tablespace temp2 tempfile '/u01/app/oracle/oradata/bxdb/temp02.dbf' size 50M;

--alter user gyj  temporary tablespace temp2;

2、利用recyclebin,drop闪回

drop table t1;

select object_name,original_name,droptime from recyclebin;

flashback table t1 to before drop;

--flashback table t1 to before drop rename to t1_old;

实验：多个名为t1的表恢复会是什么顺序???

回收站清除是按什么规则的??????

恢复表时索引也同时被恢复，但索引名称是????

drop table t1 purge; --真正删除表

三、数据库闪回配置:Books-->BAK-->Backup and Recovery Advanced User's Guide-->flashback

v$flashback_database_log

1、闪回区的大小

db_recovery_file_dest

db_recovery_file_dest_size

2、闪回日志保留时间

db_flashback_retention_target

3、设闪回

startup mount

alter database flashback on;

alter database open;

４、闪回操作要在mount下做

一般在备库中做完测试,用闪回恢复到测度前状态

flashbackup database TO TIMESTAMP(SYSDATE-1/24);

alter database open;

５、建闪回点

create restore point 恢复点名字 [guarantee flashback database]

drop restore point 恢复点名字

flashback database to  restore point re_data;

6、***场景1:

show parameter db_recover

arcive log list;

select flashback_on,force_logging from v$database;

alter database force logging;

select dbms_flashback.get_system_change_number from dual;

drop table t1 purge;

shutdown immediate;

startup mount;

flashback database to  restore point re_data;

--flashback database to scn 1511225;

alter database open resetlogs;

select * from t1;