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闪加查询、闪回版本查询、闪回事务查询

2013-09-11 20:16 344 查看

1.闪回查询:

步骤是记录当前SCN及时间,然后进行DML操作,提交后使用 timestamp和SCN进行对DML操作之前数据的查询

SQL> set time on;

19:13:57 SQL> insert into test select rownum from dual connect by rownum<=5;

5 rows inserted

19:14:47 SQL> commit;

Commit complete

19:14:49 SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER

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

                 1362061

19:18:11 SQL> delete  test where a>2;

3 rows deleted
19:18:17 SQL> commit;

Commit complete

19:21:56 SQL> select * from test as of timestamp to_timestamp('2013/06/23 19:17:00','yyyy/mm/dd hh24:mi:ss');

         A

----------

         2

         3

         4

         5

         1

19:24:23 SQL> select * from test as of scn 1362061;

         A

----------

         2

         3

         4

         5

         1

2.闪回查询--查询的是已经提交的数据

因为闪回查询的是已经提交的,这样即使数据未提交而数据库SHUTDOWN ABORT,重启后因为做实例恢复,使用闪回所查询的数据仍是已经提交的。

实验过程:查询当前SCN并执行DML操作不提交并查询当前SCN,使用闪回查询功能查询DML操作之前和之后的SCN

结果是:验证闪回查询返回的是已经提交的数据。

20:22:44 BYS@bys1>select * from test3;

        ID NAME

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

         2 b

20:22:48 BYS@bys1>select current_scn from v$database;

CURRENT_SCN

-----------

    1741868

20:26:17 BYS@bys1>delete test3;   ---不提交

1 row deleted.

各种查询:

20:26:26 BYS@bys1>select * from test3;

no rows selected

20:26:29 BYS@bys1>select current_scn from v$database;

CURRENT_SCN

-----------

    1741881

20:26:50 BYS@bys1>select * from test3 as of scn 1741868;

        ID NAME

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

         2 b

20:27:10 BYS@bys1>select * from test3 as of scn 1741881;

        ID NAME

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

         2 b

3.闪回版本查询

versions_operation:    操作类型

versions_xid:    事务编号

versions_starttime:    开始时间

versions_endtime:    结束时间,如果有值,证明这记录已非当前记录

versions_startscn:    开始SCN号

versions_endscn:    结束SCN号 如果有值,证明这记录已非当前记录

操作步骤:

19:25:28 SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER

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

                 1362268

19:37:09 SQL> col versions_starttime for a25

19:37:22 SQL> col versions_endtime for a25

19:38:02 SQL> select versions_startscn,versions_starttime, versions_endtime, versions_operation,versions_xid  from  test  versions between  timestampto_timestamp('2013/06/2319:17:00','yyyy/mm/dd
hh24:mi:ss')and  to_timestamp('2013/06/2319:20:00','yyyy/mm/dd hh24:mi:ss');

 

VERSIONS_STARTSCN VERSIONS_STARTTIME        VERSIONS_ENDTIME          VERSIONS_OPERATION VERSIONS_XID

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

          1362122 23-JUN-13 07.19.48 PM                              
D                  04001200C8020000

          1362122 23-JUN-13 07.19.48 PM                               D                  04001200C8020000

          1362122 23-JUN-13 07.19.48 PM                               D                  04001200C8020000

                                            23-JUN-13 07.19.48 PM                        

                                            23-JUN-13 07.19.48 PM                        

                                            23-JUN-13 07.19.48 PM                        

8 rows selected

4.闪回事务查询

闪回事务查询需要打开追加日志,不然无法从 flashback_transaction_query查出UNDO_SQL

20:35:42 SQL> show parameter undo

NAME                                 TYPE        VALUE

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

undo_management                      string      AUTO

undo_retention                       integer     900

undo_tablespace                      string      UNDOTBS1

20:35:57 SQL> alter database add supplemental log data;

Database altered.

20:38:01 SQL> select * from test;

         A

----------

         2

         3

         1

20:38:24 SQL> update test set a=a+10;

3 rows updated.

20:38:36 SQL> commit;

Commit complete.

20:39:37 SQL> col versions_endtime for a20

20:40:25 SQL> col versions_starttime for a20

20:40:36 SQL> set pagesize 100

20:41:56 SQL> select  versions_startscn,versions_starttime, versions_endtime, versions_operation,versions_xid  from test versions between  timestamp to_timestamp('2013/06/23 20:38:00','yyyy/mm/dd hh24:mi:ss') and to_timestamp('2013/06/23 20:39:00','yyyy/mm/dd
hh24:mi:ss');

VERSIONS_STARTSCN VERSIONS_STARTTIME   VERSIONS_ENDTIME     V
VERSIONS_XID

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

          1369588 23-JUN-13 08.38.41 PM                      U
060001003A030000

          1369588 23-JUN-13 08.38.41 PM                      U 060001003A030000

          1369588 23-JUN-13 08.38.41 PM                      U 060001003A030000                 

                                       23-JUN-13 08.38.41 PM

                                       23-JUN-13 08.38.41 PM

                                       23-JUN-13 08.38.41 PM

6 rows selected.

20:41:57 SQL> col operation for a10

20:43:07 SQL> col undo_sql for a60

20:43:20 SQL> select operation,undo_sql  from flashback_transaction_querywhere logon_user='BYS'  andundo_sql like '%TEST%';

OPERATION  UNDO_SQL

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

UPDATE     update "BYS"."TEST" set "A" = '1' where ROWID = 'AAASYyAAEAA

           AAcjAKR';

UPDATE     update "BYS"."TEST" set "A" = '3' where ROWID = 'AAASYyAAEAA

           AAcjAAE';

UPDATE     update "BYS"."TEST" set "A" = '2' where ROWID = 'AAASYyAAEAA

           AAcjAAA';

20:44:12 SQL> select operation,undo_sql  from flashback_transaction_query where logon_user='BYS'  and undo_sql like '%TEST%' andxid=HEXTORAW('060001003A030000');

OPERATION  UNDO_SQL

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

UPDATE     update "BYS"."TEST" set "A" = '1' where ROWID = 'AAASYyAAEAA

           AAcjAKR';

UPDATE     update "BYS"."TEST" set "A" = '3' where ROWID = 'AAASYyAAEAA

           AAcjAAE';

UPDATE     update "BYS"."TEST" set "A" = '2' where ROWID = 'AAASYyAAEAA

           AAcjAAA';
可以使用XID做为条件 :

20:45:01 SQL> select operation,undo_sql  from flashback_transaction_querywhere  xid=HEXTORAW('060001003A030000');

OPERATION  UNDO_SQL

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

UPDATE     update "BYS"."TEST" set "A" = '1' where ROWID = 'AAASYyAAEAA

           AAcjAKR';

UPDATE     update "BYS"."TEST" set "A" = '3' where ROWID = 'AAASYyAAEAA

           AAcjAAE';

UPDATE     update "BYS"."TEST" set "A" = '2' where ROWID = 'AAASYyAAEAA

           AAcjAAA';

BEGIN
可以使用XID做为条件 :

20:45:17 SQL> select operation,undo_sql  from flashback_transaction_querywhere  xid='060001003A030000';

OPERATION  UNDO_SQL

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

UPDATE     update "BYS"."TEST" set "A" = '1' where ROWID = 'AAASYyAAEAA

           AAcjAKR';

UPDATE     update "BYS"."TEST" set "A" = '3' where ROWID = 'AAASYyAAEAA

           AAcjAAE';

UPDATE     update "BYS"."TEST" set "A" = '2' where ROWID = 'AAASYyAAEAA

           AAcjAAA';

BEGIN
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