【Oracle Database】闪回（FlashBack）

闪回版本查询
SQL> set line 200
SQL> col starttime for a30
SQL> col endtime for a30
SQL> col operation for a30

SQL> select to_char(versions_starttime,'yyyy-mm-dd hh34:mi:ss') starttime,to_char(versions_endtime,'yyyy-mm-dd hh34:mi:ss') endtime,
   versions_xid xid,versions_operation operation from soe.customers versions
   between timestamp to_date('2018-09-22 14:00:00','yyyy-mm-dd hh34:mi:ss') and sysdate where versions_xid is not null;
STARTTIME                      ENDTIME                        XID              OPERATION
------------------------------ ------------------------------ ---------------- ------------------------------
2018-09-22 14:00:36                                           05001100B8030000 U
2018-09-22 13:59:59                                           05000700B8030000 U
2018-09-22 14:00:25                                           08001B00CC030000 U
2018-09-22 14:00:14                                           05001000B8030000 I
2018-09-22 14:00:20                                           09001700C9030000 I
2018-09-22 14:00:05                                           0B00200041000000 I
2018-09-22 14:00:05                                           09000700CA030000 I
2018-09-22 14:00:11                                           03001800B4030000 I
8 rows selected.

闪回事务查询
SQL> select undo_sql from flashback_transaction_query where xid = hextoraw('03001800B4030000');
UNDO_SQL
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
delete from "SOE"."LOGON" where ROWID = 'AAAVU+AAGAAAavRAB6';
delete from "SOE"."CARD_DETAILS" where ROWID = 'AAAVU4AAHAAAQEoABz';
delete from "SOE"."ADDRESSES" where ROWID = 'AAAVU3AAHAAAbuoAAy';
delete from "SOE"."CUSTOMERS" where ROWID = 'AAAVU2AAGAAAaqxAAO';

SQL> select undo_sql from flashback_transaction_query where xid = hextoraw('08001B00CC030000');
UNDO_SQL
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
update "SOE"."CUSTOMERS" set "PREFERRED_ADDRESS" = '1162533' where ROWID = 'AAAVU2AAGAAACC9AAS';
delete from "SOE"."ADDRESSES" where ROWID = 'AAAVU3AAHAAAbumAA5';

闪回表--scn
SQL> alter table soe.customers enable row movement;

Table altered.
SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    975317

SQL> select dbms_flashback.get_system_change_number from dual; 

GET_SYSTEM_CHANGE_NUMBER
------------------------
                 1217679
                 
SQL> delete from soe.customers where nls_territory = 'Korea';

12470 rows deleted.

SQL> commit;

Commit complete.


SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    962847

SQL> flashback table soe.customers to scn 1217679;

Flashback complete.

SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    975317
    
闪回表--timestamp    
SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    975317

SQL> select dbms_flashback.get_system_change_number from dual; 

GET_SYSTEM_CHANGE_NUMBER
------------------------
                 1221943

SQL> select scn_to_timestamp(1221943) scn from dual;

SCN
---------------------------------------------------------------------------
23-SEP-18 04.17.24.000000000 PM


SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    975317


SQL> select dbms_flashback.get_system_change_number from dual;

GET_SYSTEM_CHANGE_NUMBER
------------------------
                 1222481

SQL> select scn_to_timestamp(1222481) scn from dual;

SCN
---------------------------------------------------------------------------
23-SEP-18 04.22.21.000000000 PM


SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    975340

SQL> flashback table soe.customers to timestamp to_timestamp('2018-09-23 16:17:24','yyyy-mm-dd hh34:mi:ss');

Flashback complete.


SQL> select count(*) from soe.customers;

  COUNT(*)
----------
    975317

闪回删除
SQL> show parameter recyclebin;
NAME                                 TYPE                              VALUE
------------------------------------ --------------------------------- ------------------------------
recyclebin                           string                            ON

SQL> drop table warehouses;
Table dropped.

SQL> show recyclebin;
ORIGINAL NAME    RECYCLEBIN NAME                OBJECT TYPE  DROP TIME
---------------- ------------------------------ ------------ -------------------
WAREHOUSES       BIN$doc0/FwhEVPgU8kBqMBrow==$0 TABLE        2018-09-23:17:07:50

SQL> flashback table warehouses to before drop;
Flashback complete.

SQL> select count(*) from warehouses;
  COUNT(*)
----------
      1000
      
SQL> alter index "BIN$doc0/FwgEVPgU8kBqMBrow==$0" rename to warehouses_pk;
Index altered.

SQL> alter table warehouses rename constraint "BIN$doc0/FwfEVPgU8kBqMBrow==$0" to warehouses_pk;
Table altered.

闪回数据库
SQL> startup mount;
ORACLE instance started.

Total System Global Area 1068937216 bytes
Fixed Size                  2260088 bytes
Variable Size             322962312 bytes
Database Buffers          687865856 bytes
Redo Buffers               55848960 bytes
Database mounted.

SQL> alter database flashback on;
Database altered.

SQL> alter database open;
Database altered.

SQL> select dbid,name,flashback_on,current_scn from v$database;

      DBID NAME                        FLASHBACK_ CURRENT_SCN
---------- --------------------------- ---------- -----------
1085678857 KING                        YES            1229459

SQL> show parameter db_flashback

NAME                                 TYPE                              VALUE
------------------------------------ --------------------------------- ------------------------------
db_flashback_retention_target        integer                           1440

SQL> alter session set nls_date_format='yyyy-mm-dd hh34:mi:ss';
Session altered.

SQL> select count(*) from orders;

  COUNT(*)
----------
   1430069
   
SQL> select sysdate from dual;
SYSDATE
-------------------
2018-09-24 13:43:57

SQL> truncate table orders;
Table truncated.

SQL> select count(*) from orders;

  COUNT(*)
----------
         0
         
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

SQL> startup mount;
ORACLE instance started.

Total System Global Area 1068937216 bytes
Fixed Size                  2260088 bytes
Variable Size             322962312 bytes
Database Buffers          687865856 bytes
Redo Buffers               55848960 bytes
Database mounted.

SQL> flashback database to timestamp to_timestamp('2018-09-24 13:43:57','yyyy-mm-dd hh34:mi:ss');
Flashback complete.

SQL> alter database open read only;
Database altered.

SQL> conn soe/soe
Connected.
SQL> select count(*) from orders;

  COUNT(*)
----------
   1430069
   
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

SQL> startup mount
ORACLE instance started.

Total System Global Area 1068937216 bytes
Fixed Size                  2260088 bytes
Variable Size             322962312 bytes
Database Buffers          687865856 bytes
Redo Buffers               55848960 bytes
Database mounted.

SQL> alter database open resetlogs;
Database altered.

SQL> conn soe/soe
Connected.
SQL> select count(*) from orders;

  COUNT(*)
----------
   1430069

总结：闪回版本查询，闪回事务查询，闪回表与UNDO有关，与闪回日志没有任何关系
     闪回删除与recyclebin有关，与闪回日志没有任何关系
     闪回数据库与闪回日志有关