10gR2 需要將一個普通錶轉爲按月分區提高查詢效率
測試如下：
一、建立測試表
SQL> CREATE TABLE T(ID NUMBER ,TIME DATE);
Table created.
SQL> DESC T;
Name Null? Type
----------------------------------------- -------- ----------------------------
ID NUMBER
TIME DATE
SQL> INSERT INTO T SELECT ROWNUM,CREATED FROM ALL_OBJECTS;
17979 rows created.
SQL> SET TIMING ON
SQL> select count(*) from t;
COUNT(*)
----------
17979
二、測試表是否可以在線重定義
SQL> EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('test','T', DBMS_REDEFINITION.CONS_USE_PK);
BEGIN DBMS_REDEFINITION.CAN_REDEF_TABLE('test','T', DBMS_REDEFINITION.CONS_USE_PK); END;
*
ERROR at line 1:
ORA-06550: line 1, column 53:
PLS-00201: identifier 'DBMS_REDEFINITION' must be declared
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
出錯原因是沒有賦予‘DBMS_REDEFINITION' 的執行權限。解決的辦法是：
dba用戶授予權限
SQL> GRANT ALL ON SYS.DBMS_REDEFINITION TO TEST;
Grant succeeded.
SQL> GRANT CREATE ANY TABLE, ALTER ANY TABLE, DROP ANY TABLE, LOCK ANY TABLE, SELECT ANY TABLE TO TEST;
Grant succeeded.
回到test用戶繼續驗證
SQL> EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('test', 'T', DBMS_REDEFINITION.CONS_USE_PK);
BEGIN DBMS_REDEFINITION.CAN_REDEF_TABLE('test', 'T', DBMS_REDEFINITION.CONS_USE_PK); END;
*
ERROR at line 1:
ORA-12089: cannot online redefine table "test"."T" with no primary key
ORA-06512: at "SYS.DBMS_REDEFINITION", line 137
ORA-06512: at "SYS.DBMS_REDEFINITION", line 1479
ORA-06512: at line 1
如果沒有定義主鍵會提示以上錯誤信息
建立主鍵：
SQL> alter table t add constraint pk_t primary key(id);
Table altered.
再次驗證成功
SQL> EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('test','T',DBMS_REDEFINITION.CONS_USE_PK);
PL/SQL procedure successfully completed.
三、建立中間表及分區
SQL> select to_char(min(time),'YYYY-MM-DD HH24:MI:SS') from t;
TO_CHAR(MIN(TIME),'
-------------------
2003-06-13 21:11:01
SQL> select to_char(max(time),'YYYY-MM-DD HH24:MI:SS') from t;
TO_CHAR(MAX(TIME),'
-------------------
2013-05-07 21:40:35
SQL> CREATE TABLE T_NEW (ID NUMBER PRIMARY KEY, TIME DATE) PARTITION BY RANGE (TIME)
2 (PARTITION T_2003 VALUES LESS THAN (TO_DATE('2004-1-1', 'YYYY-MM-DD')),
3 PARTITION T_2004 VALUES LESS THAN (TO_DATE('2005-1-1', 'YYYY-MM-DD')),
4 PARTITION T_2005 VALUES LESS THAN (TO_DATE('2006-1-1', 'YYYY-MM-DD')),
5 PARTITION T_2006 VALUES LESS THAN (TO_DATE('2007-1-1', 'YYYY-MM-DD')),
6 PARTITION T_2007 VALUES LESS THAN (TO_DATE('2008-1-1', 'YYYY-MM-DD')),
7 PARTITION T_2008 VALUES LESS THAN (TO_DATE('2009-1-1', 'YYYY-MM-DD')),
8 PARTITION T_2009 VALUES LESS THAN (TO_DATE('2010-1-1', 'YYYY-MM-DD')),
9 PARTITION T_2010 VALUES LESS THAN (TO_DATE('2011-1-1', 'YYYY-MM-DD')),
10 PARTITION T_2011 VALUES LESS THAN (TO_DATE('2012-1-1', 'YYYY-MM-DD')),
11 PARTITION T_2012 VALUES LESS THAN (TO_DATE('2013-1-1', 'YYYY-MM-DD')),
12 PARTITION T_2013 VALUES LESS THAN (TO_DATE('2014-1-1', 'YYYY-MM-DD')));
四、在線重新定義操作
SQL> exec dbms_redefinition.start_redef_table('TEST','T','T_NEW');
PL/SQL procedure successfully completed.
一些問題：
建立過程關於物化視圖的問題
SQL> desc user_mviews;
Name Null? Type
----------------------------------------- -------- ----------------------------
OWNER NOT NULL VARCHAR2(30)
MVIEW_NAME NOT NULL VARCHAR2(30)
CONTAINER_NAME NOT NULL VARCHAR2(30)
....省略
SQL> select mview_name from user_mviews;
no rows selected
SQL> EXEC DBMS_REDEFINITION.START_REDEF_TABLE('test','T','T_NEW');
PL/SQL procedure successfully completed.
SQL> select mview_name from user_mviews;
MVIEW_NAME
------------------------------
T_NEW
SQL>
#start後會產生一個物化視圖，如果中途失敗不做abort會導致物化視圖一次存在，下一次操作時會報：
SQL> EXEC DBMS_REDEFINITION.START_REDEF_TABLE('test', 'T', 'T_NEW');
BEGIN DBMS_REDEFINITION.START_REDEF_TABLE('test', 'T', 'T_NEW'); END;
*
ERROR at line 1:
ORA-12091: cannot online redefine table "test"."T" with
materialized views
ORA-06512: at "SYS.DBMS_REDEFINITION", line 50
ORA-06512: at "SYS.DBMS_REDEFINITION", line 1343
ORA-06512: at line 1
SQL> drop materialized view log on T;
ORA-14400: inserted partition key does not map to any partition
這個報錯的意思是分區表建立時有值在分區表之外，未被包含，可以查詢下數據把缺失的分區表建立起來
參考：
SQL> select to_char(max(time),'YYYY-MM-DD HH24:MI:SS') from t;
TO_CHAR(MAX(TIME),'
-------------------
2014-05-01 21:40:35
SQL> select partition_name from user_tab_partitions where table_name='T_NEW';
PARTITION_NAME
------------------------------
T_2003
T_2004
T_2005
T_2006
T_2007
T_2008
T_2009
T_2010
T_2011
T_2012
T_2013
11 rows selected.
SQL> ALTER TABLE T_NEW ADD PARTITION T_2014 VALUES LESS THAN (TO_DATE('2015-01-01','YYYY-MM-DD'));
Table altered.
SQL> select partition_name from user_tab_partitions where table_name='T_NEW';
PARTITION_NAME
------------------------------
T_2003
T_2004
T_2005
T_2006
T_2007
T_2008
T_2009
T_2010
T_2011
T_2012
T_2013
T_2014
12 rows selected.
五、執行重定義後的分區數據同步
SQL> exec dbms_redefinition.sync_interim_table('TEST','T','T_NEW');
PL/SQL procedure successfully completed.
六、完成在線重定義操作
SQL> EXEC DBMS_REDEFINITION.FINISH_REDEF_TABLE('TEST','T','T_NEW');
PL/SQL procedure successfully completed.
如果執行在線重定義的過程中出錯
可以在執行dbms_redefinition.start_redef_table之後到執行dbms_redefinition.finish_redef_table之前的時間裏
執行：DBMS_REDEFINITION.abort_redef_table('test', 't', 't_new')以放棄執行在線重定義。