这几天看看业务有些日志表需要从堆表转成分区表，想想从9开始有了在线重定义，决定就用这个解决吧，而且做的时候对表不锁定，可以做DDL。好处还是挺多的。
步骤：
重定义的方法有两种：By key和by rowid，默认是主键模式
1：验证表是否可以重定义
EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('username', 'tablename');
2:创建一个空的分区中间表，具体建表语句这里忽略
3：开始重定义
EXEC DBMS_REDEFINITION.START_REDEF_TABLE('username', 'tablename', 'new_tablename',null);
4: 复制依赖对象（比如触发器，索引，约束，权限，等等）
EXEC DBMS_REDEFINITION.COPY_TABLE_DEPENDENTS()
5:同步中间表
EXEC DBMS_REDEFINITION.SYNC_INTERIM_TABLE('username', 'tablename', 'new_tablename');
6:结束重定义
EXEC DBMS_REDEFINITION.FINISH_REDEF_TABLE('username', 'tablename', 'new_tablename');

注意：
If START_REDEF_TABLE fails for any reason, you must call ABORT_REDEF_TABLE, otherwise subsequent attempts to redefine the table will fail.
Privileges Required for the DBMS_REDEFINITION Package

Execute privileges on the DBMS_REDEFINITION package are granted to EXECUTE_CATALOG_ROLE. In addition to having execute privileges on this package, you must be granted the following privileges:

CREATE ANY TABLE

ALTER ANY TABLE

DROP ANY TABLE

LOCK ANY TABLE

SELECT ANY TABLE

The following additional privileges are required to execute COPY_TABLE_DEPENDENTS:

CREATE ANY TRIGGER

CREATE ANY INDEX