oracle 11g 在线重定义（online redefinition）介绍

【实验】 对于在线重定义的步骤，这里不再具体说明，我们通过一个实验来演示一下，下面是一个把普通表转换成分区表在线重定义的例子 一、首先创建用户tj，并授予能够完成在线重定义的权限和角色 SQL create user tj identified by tj 2 default tablespace u

【实验】

对于在线重定义的步骤，这里不再具体说明，我们通过一个实验来演示一下，下面是一个把普通表转换成分区表在线重定义的例子

一、首先创建用户tj，并授予能够完成在线重定义的权限和角色

SQL> create user tj identified by tj

  2  default tablespace users

  3  temporary tablespace temp

  4  quota unlimited on users;

User created.

SQL> GRANT CREATE SESSION, CREATE ANY TABLE,ALTER ANY TABLE,

  2        DROP ANY TABLE, LOCK ANY TABLE  ,SELECT ANY TABLE,

  3        CREATE ANY INDEX,CREATE ANY TRIGGER

  4  TO TJ;

Grant succeeded.

SQL> GRANT EXECUTE_CATALOG_ROLE TO TJ;

Grant succeeded.

二、使用TJ用户登录，创建表DEMO，作为在线重定义的原始表，在表上添加主键和一个索引

SQL> conn tj/tj

Connected.

SQL> create table demo as select empno,ename,sal,deptno from scott.emp;

Table created.

SQL> set linesize 120

SQL> set pagesize 60

SQL> select * from demo;

     EMPNO ENAME             SAL     DEPTNO

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

      7369 SMITH            6000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7566 JONES            2975         20

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7782 CLARK            2450         10

      7788 SCOTT            1000         20

      7839 KING             5000         10

      7844 TURNER           1500         30

      7876 ADAMS            1100         20

      7900 JAMES             950         30

      7902 FORD             3000         20

      7934 MILLER           1300         10

14 rows selected.

SQL>  alter table demo add constraint demo_pk primary key(empno);

Table altered.

SQL> create index demo_idx on demo(ename);

Index created.

SQL> select object_id,object_name,object_type,status from user_objects;

 OBJECT_ID OBJECT_NAME     OBJECT_TYPE         STATUS

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

     77125 DEMO            TABLE               VALID

     77126 DEMO_PK         INDEX               VALID

     77127 DEMO_IDX        INDEX               VALID

三、使用CAN_REDEF_TABLE确认表是否可以做在线重定义

SQL> EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('TJ', 'DEMO');

PL/SQL procedure successfully completed.

四、创建中间表，当然这是一个空表，使用START_REDEF_TABLE开始在线重定义

SQL> create table demo_tmp

  2  partition by range(deptno)

  3  (

  4   partition p1 values less than (11),

  5   partition p2 values less than (21),

  6   partition p3 values less than (31)

  7  )

  8  as

  9  select * from demo where 1=2;

Table created.

SQL> select object_id,object_name,object_type,status from user_objects;

 OBJECT_ID OBJECT_NAME     OBJECT_TYPE         STATUS

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

     77129 DEMO_TMP        TABLE               VALID

     77130 DEMO_TMP        TABLE PARTITION     VALID

     77132 DEMO_TMP        TABLE PARTITION     VALID

     77131 DEMO_TMP        TABLE PARTITION     VALID

     77127 DEMO_IDX        INDEX               VALID

     77126 DEMO_PK         INDEX               VALID

     77125 DEMO            TABLE               VALID

7 rows selected.

SQL> BEGIN

  2      DBMS_REDEFINITION.START_REDEF_TABLE('TJ', 'DEMO', 'DEMO_TMP');

  3  END;

  4  /

PL/SQL procedure successfully completed.

SQL> select object_id,object_name,object_type,status from user_objects;

 OBJECT_ID OBJECT_NAME     OBJECT_TYPE         STATUS

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

     77134 RUPD$_DEMO      TABLE               VALID

     77133 MLOG$_DEMO      TABLE               VALID

     77129 DEMO_TMP        TABLE               VALID

     77130 DEMO_TMP        TABLE PARTITION     VALID

     77132 DEMO_TMP        TABLE PARTITION     VALID

     77131 DEMO_TMP        TABLE PARTITION     VALID

     77127 DEMO_IDX        INDEX               VALID

     77126 DEMO_PK         INDEX               VALID

     77125 DEMO            TABLE               VALID

9 rows selected.

我们注意到Oracle新建了两张表RUPD$_DEMO和MLOG$_DEMO，其实Oracle在线重定义是通过物化视图的LOG来实现的。做完这一步后，在中间表中也有了相同的数据

SQL> select * from demo;

     EMPNO ENAME             SAL     DEPTNO

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

      7369 SMITH            6000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7566 JONES            2975         20

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7782 CLARK            2450         10

      7788 SCOTT            1000         20

      7839 KING             5000         10

      7844 TURNER           1500         30

      7876 ADAMS            1100         20

      7900 JAMES             950         30

      7902 FORD             3000         20

      7934 MILLER           1300         10

14 rows selected.

SQL> select * from demo_tmp;

     EMPNO ENAME             SAL     DEPTNO

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

      7782 CLARK            2450         10

      7839 KING             5000         10

      7934 MILLER           1300         10

      7369 SMITH            6000         20

      7566 JONES            2975         20

      7788 SCOTT            1000         20

      7876 ADAMS            1100         20

      7902 FORD             3000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7844 TURNER           1500         30

      7900 JAMES             950         30

14 rows selected.

 

五、使用COPY_TABLE_DEPENDENTS把原始表的权限、约束、索引、物化视图LOG在中间表上创建一份

SQL> set serveroutput on

SQL> var v_err number

SQL> exec DBMS_REDEFINITION.COPY_TABLE_DEPENDENTS('TJ', 'DEMO', 'DEMO_TMP',  NUM_ERRORS => :V_ERR);

PL/SQL procedure successfully completed.

SQL> print v_err

     V_ERR

----------

         0

SQL> select object_id,object_name,object_type,status from user_objects;

 OBJECT_ID OBJECT_NAME     OBJECT_TYPE         STATUS

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

     77137 TMP$$_DEMO_PK0  INDEX               VALID

     77138 TMP$$_DEMO_IDX0 INDEX               VALID

     77134 RUPD$_DEMO      TABLE               VALID

     77133 MLOG$_DEMO      TABLE               VALID

     77129 DEMO_TMP        TABLE               VALID

     77130 DEMO_TMP        TABLE PARTITION     VALID

     77132 DEMO_TMP        TABLE PARTITION     VALID

     77131 DEMO_TMP        TABLE PARTITION     VALID

     77127 DEMO_IDX        INDEX               VALID

     77126 DEMO_PK         INDEX               VALID

     77125 DEMO            TABLE               VALID

11 rows selected.

SQL> select table_name,index_name,status from user_indexes where table_name='DEMO_TMP';

TABLE_NAME                     INDEX_NAME                     STATUS

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

DEMO_TMP                       TMP$$_DEMO_IDX0                VALID

DEMO_TMP                       TMP$$_DEMO_PK0                 VALID

这里我们看到，Oracle在中间表DEMO_TMP上又根据原始表DEMO建了两个索引

 

六、如果在线重定义的时间比较长，而在这个过程中有其他的DML语句操作在原始表上，Oracle通过SYNC_INTERIM_TABLE来做同步

SQL> insert into demo values(1000,'TOMMY',1350,10);

1 row created.

SQL> commit;

Commit complete.

SQL> select * from demo;

     EMPNO ENAME             SAL     DEPTNO

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

      7369 SMITH            6000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7566 JONES            2975         20

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7782 CLARK            2450         10

      7788 SCOTT            1000         20

      7839 KING             5000         10

      7844 TURNER           1500         30

      7876 ADAMS            1100         20

      7900 JAMES             950         30

      7902 FORD             3000         20

      7934 MILLER           1300         10

      1000 TOMMY            1350         10

15 rows selected.

SQL> select * from demo_tmp;

     EMPNO ENAME             SAL     DEPTNO

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

      7782 CLARK            2450         10

      7839 KING             5000         10

      7934 MILLER           1300         10

      7369 SMITH            6000         20

      7566 JONES            2975         20

      7788 SCOTT            1000         20

      7876 ADAMS            1100         20

      7902 FORD             3000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7844 TURNER           1500         30

      7900 JAMES             950         30

14 rows selected.

上面插入一条记录到原始表DEMO中，中间表上是看不到的，这个操作会被记录在MLOG$_DEMO中，需要我们主动同步到DEMO_TMP中

SQL> desc MLOG$_DEMO

 Name                                                              Null?    Type

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

 EMPNO                                                                      NUMBER(4)

 DMLTYPE$$                                                                  VARCHAR2(1)

 OLD_NEW$$                                                                  VARCHAR2(1)

 CHANGE_VECTOR$$                                                            RAW(255)

 XID$$                                                                      NUMBER

SQL> select empno,DMLTYPE$$,OLD_NEW$$ from MLOG$_DEMO;

     EMPNO D O

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

      1000 I N

SQL> EXEC DBMS_REDEFINITION.SYNC_INTERIM_TABLE('TJ', 'DEMO', 'DEMO_TMP');

PL/SQL procedure successfully completed.

SQL> select * from demo;

     EMPNO ENAME             SAL     DEPTNO

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

      7369 SMITH            6000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7566 JONES            2975         20

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7782 CLARK            2450         10

      7788 SCOTT            1000         20

      7839 KING             5000         10

      7844 TURNER           1500         30

      7876 ADAMS            1100         20

      7900 JAMES             950         30

      7902 FORD             3000         20

      7934 MILLER           1300         10

      1000 TOMMY            1350         10

15 rows selected.

SQL> select * from demo_tmp;

     EMPNO ENAME             SAL     DEPTNO

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

      7782 CLARK            2450         10

      7839 KING             5000         10

      7934 MILLER           1300         10

      1000 TOMMY            1350         10

      7369 SMITH            6000         20

      7566 JONES            2975         20

      7788 SCOTT            1000         20

      7876 ADAMS            1100         20

      7902 FORD             3000         20

      7499 ALLEN            1600         30

      7521 WARD             1250         30

      7654 MARTIN           1250         30

      7698 BLAKE            2850         30

      7844 TURNER           1500         30

      7900 JAMES             950         30

15 rows selected.

SQL> select empno,DMLTYPE$$,OLD_NEW$$ from MLOG$_DEMO;

no rows selected

严格意义上来说，第六步不是必须的，当做第七步的时候，Oracle会自动同步数据，不过这样会加长表不可用的时间，所以还是建议我们单独做

七、完成在线重定义，在这一步中，要对原始表DEMO以独占的方式锁定。

SQL> EXEC DBMS_REDEFINITION.FINISH_REDEF_TABLE('TJ', 'DEMO', 'DEMO_TMP');

PL/SQL procedure successfully completed.

SQL> select object_id,object_name,object_type,status from user_objects;

 OBJECT_ID OBJECT_NAME     OBJECT_TYPE         STATUS

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

     77129 DEMO            TABLE               VALID

     77130 DEMO            TABLE PARTITION     VALID

     77131 DEMO            TABLE PARTITION     VALID

     77132 DEMO            TABLE PARTITION     VALID

     77125 DEMO_TMP        TABLE               VALID

     77138 DEMO_IDX        INDEX               VALID

     77127 TMP$$_DEMO_IDX0 INDEX               VALID

     77137 DEMO_PK         INDEX               VALID

     77126 TMP$$_DEMO_PK0  INDEX               VALID

9 rows selected.

操作完成后，我们发现RUPD$_DEMO和MLOG$_DEMO被自动删除，另外我们也可以看到重定义的效果了

SQL> SELECT TABLE_NAME, PARTITION_NAME FROM USER_TAB_PARTITIONS WHERE TABLE_NAME = 'DEMO';

TABLE_NAME                     PARTITION_NAME

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

DEMO                           P1

DEMO                           P2

DEMO                           P3

SQL> select table_name,index_name,status from user_indexes where table_name='DEMO';

TABLE_NAME                     INDEX_NAME                     STATUS

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

DEMO                           DEMO_IDX                       VALID

DEMO                           DEMO_PK                        VALID

SQL> select table_name,index_name,status from user_indexes where table_name='DEMO_TMP';

TABLE_NAME                     INDEX_NAME                     STATUS

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

DEMO_TMP                       TMP$$_DEMO_IDX0                VALID

DEMO_TMP                       TMP$$_DEMO_PK0                 VALID

SQL> select * from demo partition(p1);

     EMPNO ENAME             SAL     DEPTNO

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

      7782 CLARK            2450         10

      7839 KING             5000         10

      7934 MILLER           1300         10

      1000 TOMMY            1350         10