原文：

http://zhidao.baidu.com/link?url=WDmPISaSZGZ5M8Dci_lmsLgl531wkzG7GcDcTW3fjD3EXJBEq_tdu12zyC7uWKFxBsIW9SLbhpoC6e_9eW7xc9cQ0ELQEBR8G6at1Fb_7gC 

做了个测试 如下

15:02:32 SQL> create table test(id int,name varchar2(10)) partition by range(id)
15:03:07   2  ( partition p1 values less than(100),
15:03:13   3  partition p2 values less than(200),
15:03:20   4  partition pmax values less than(maxvalue));

Table created.

15:03:33 SQL> insert into test values(1,'test1');

1 row created.

15:03:50 SQL> insert into test values(101,'test1');

1 row created.

15:03:57 SQL> insert into test values(301,'test1');

1 row created.

15:04:02 SQL> commit;

Commit complete.

15:09:07 SQL> select * from test partition(p1);

        ID NAME
---------- ----------
         1 test1

15:09:17 SQL> select * from test partition(p2);

        ID NAME
---------- ----------
       101 test1

15:09:35 SQL> select * from test partition(pmax);

        ID NAME
---------- ----------
       301 test1

每个分区里面都有数据
下面模拟一个连续的插入到最大分区上面
15:09:39 SQL> declare
15:09:47   2  i int;
15:09:47   3  begin
15:09:47   4  for i in 1..100 loop
15:09:47   5  insert into test values(40*i,'test'||i);
15:09:47   6  dbms_lock.sleep(2);
15:09:47   7 end loop;
15:09:47   8  commit;
15:09:47   9 end;
15:09:48  10  /
这个大概执行10秒左右后插入的数据都在pmax分区里面 

新开个窗口 执行 分列分区的命令
SQL> alter table test split partition pmax at(1000) into (partition p3,partition pmx);
alter table test split partition pmax at(1000) into (partition p3,partition pmx)
            *
ERROR at line 1:
ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired

这结果很明显了  有数据在操作时无法分裂

接下来   按个语句  再执行  这时候数据只插入在头两个分区

15:14:46 SQL> declare
15:16:40   2  i int;
15:16:40   3  begin
15:16:40   4  for i in 1..49 loop
15:16:40   5  insert into test values(4*i,'test'||i);
15:16:40   6  dbms_lock.sleep(2);
15:16:40   7 end loop;
15:16:40   8  commit;
15:16:40   9  end;
15:16:40  10  /

再在另一个窗口执行
15:17:14 SQL> alter table test split partition pmax at(1000) into (partition p3,partition pmx);

Table altered.

此时分裂分区成功

也就是说有数据在操作那个分区时无法分裂，当数据没操作需要分裂的分区时可以拆分，从结构上来讲 每个分区本身就是不同的segment