Oracle 12.2新特性----在线move表

下面以11.2.0.4和12.2.0.1这两个版本为对比,观察这一新特性。
1、11.2.0.4版本的move操作
--创建测试表
zx@ORA11G>create table t as select * from dba_objects;
 
Table created.
 
Elapsed: 00:00:00.26
zx@ORA11G>insert into t select * from t;
 
79608 rows created.
 
Elapsed: 00:00:00.22
zx@ORA11G>/
 
159216 rows created.
 
Elapsed: 00:00:00.38
zx@ORA11G>/
 
318432 rows created.
 
Elapsed: 00:00:03.63
zx@ORA11G>/
 
636864 rows created.
 
Elapsed: 00:00:05.40
zx@ORA11G>/
 
1273728 rows created.
 
Elapsed: 00:00:24.57
 
zx@ORA11G>select bytes/1024/1024 from user_segments;
 
BYTES/1024/1024
---------------
        392
 
Elapsed: 00:00:00.07
zx@ORA11G>commit;
 
Commit complete.
 
Elapsed: 00:00:00.01
zx@ORA11G>alter system flush buffer_cache;
 
System altered.
 
Elapsed: 00:00:27.90
--不做move操作时delete操作时间
zx@ORA11G>delete from t where object_name='T';
 
32 rows deleted.
 
Elapsed: 00:00:00.13
zx@ORA11G>rollback;
 
Rollback complete.
--执行move
--session 1
zx@ORA11G>select userenv('sid') from dual;
 
USERENV('SID')
--------------
      1150
--session 2 
zx@ORA11G>select userenv('sid') from dual;
 
USERENV('SID')
--------------
        15
--session 1
zx@ORA11G>alter table t move tablespace examples;
 
Table altered.
 
Elapsed: 00:00:02.45
--session 2
zx@ORA11G>delete from t where object_name='T';
 
32 rows deleted.
 
Elapsed: 00:00:02.18
zx@ORA11G>rollback;
 
Rollback complete.
--session 3
sys@ORA11G>select /*+ rule */ sid,lmode,request,type,block from v$lock where sid in (1150,15);
 
      SID  LMODE    REQUEST TY    BLOCK
---------- ---------- ---------- -- ----------
      1150        6          0 TM      1
      1150        4          0 AE      0
      1150        6          0 TS      0
      1150        6          0 TX      0
      1150        2          0 XR      0
    15      4          0 AE      0
    15      0          3 TM      0
 
7 rows selected

从上面的查询中可以看出表move操作阻塞了delete操作。
2、下面来看12.2版本的在线move操作,需要添加online关键字。
--创建测试表
zx@ORA12C>select segment_name,bytes/1024/1024 from user_segments;
 
SEGMENT_NAME              BYTES/1024/1024
------------------------------ ---------------
T                      392
--在没有move时delete操作时间
zx@ORA12C>delete from t where object_name='USER_TABLES';
 
256 rows deleted.
 
Elapsed: 00:00:00.44
zx@ORA12C>rollback;
 
Rollback complete.
--session 1
zx@ORA12C>select userenv('sid') from dual;
 
USERENV('SID')
--------------
        23
--session 2
zx@ORA12C>select userenv('sid') from dual;
 
USERENV('SID')
--------------
        27
--执行move操作
--session 1
zx@ORA12C>alter table t move online tablespace examples;
 
Table altered.
 
Elapsed: 00:00:34.73
--session 2
zx@ORA12C>delete from t where object_name='USER_TABLES';
 
256 rows deleted.
 
Elapsed: 00:00:00.97
zx@ORA12C>rollback;
 
Rollback complete.
--session 3
sys@ORA12C>select /*+ rule */ sid,lmode,request,type,block from v$lock where sid in (23,27);
 
      SID  LMODE    REQUEST TY    BLOCK
---------- ---------- ---------- -- ----------
    27      3          0 TM      0
    27      4          0 AE      0
    27      6          0 TX      0
    23      4          0 AE      0
    23      6          0 OD      0
    23      3          0 DL      0
    23      3          0 DL      0
    23      6          0 TS      0
    23      6          0 TM      0
    23      4          0 TM      0
    23      6          0 TM      0
    23      3          0 TM      0
    23      6          0 TX      0
    23      6          0 TX      0
    23      3          0 TM      0
    23      3          0 TM      0
 
16 rows selected.

从上面的操作可以看出12.2的move操作没有阻塞delete操作。
参考:http://docs.oracle.com/database/122/NEWFT/new-features.htm#GUID-BEEEA34D-3D81-4360-887C-A92BC711816D

猜你喜欢

转载自www.linuxidc.com/Linux/2017-07/145579.htm
今日推荐