需要将一个普通表转为按月分区提高查询效率
测试如下：
一、建立测试表
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、测试表是否可以在线重定义
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
出错原因是没有赋予‘DBMS_REDEFINITION' 的执行权限。解决的办法是：
dba用户授予权限
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用户继续验证
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
如果没有定义主键会提示以上错误信息
建立主键：
SQL> alter table t add constraint pk_t primary key(id); Table altered.
再次验证成功
SQL> EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('test','T',DBMS_REDEFINITION.CONS_USE_PK); PL/SQL procedure successfully completed.
三、建立中间表及分区
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、在线重新定义操作
SQL> exec dbms_redefinition.start_redef_table('TEST','T','T_NEW'); PL/SQL procedure successfully completed.
一些问题：
建立过程关于物化视图的问题
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后会产生一个物化视图，如果中途失败不做abort会导致物化视图一次存在，下一次操作时会报：
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
这个报错的意思是分区表建立时有值在分区表之外，未被包含，可以查询下数据把缺失的分区表建立起来
参考：
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、执行重定义后的分区数据同步
SQL> exec dbms_redefinition.sync_interim_table('TEST','T','T_NEW'); PL/SQL procedure successfully completed.
六、完成在线重定义操作
SQL> EXEC DBMS_REDEFINITION.FINISH_REDEF_TABLE('TEST','T','T_NEW'); PL/SQL procedure successfully completed.
如果执行在线重定义的过程中出错
可以在执行dbms_redefinition.start_redef_table之后到执行dbms_redefinition.finish_redef_table之前的时间里
执行：DBMS_REDEFINITION.abort_redef_table('test', 't', 't_new')以放弃执行在线重定义。