關于修改資料庫的global_name，在metalink上提供了2種方法，在實際使用時，如果global_name中帶有域名，而想要修改為不帶域名字尾，就需要注意選擇合适的方法來修改，否則會修改失敗。
Two methods can be used to rename the global_name for the database:
1. UPDATE GLOBAL_NAME SET GLOBAL_NAME = '[.db_domain]';
Once the global name is in the correct form, further changes can be made using
the supported command:
2. ALTER DATABASE RENAME GLOBAL_NAME TO [.db_domain];
分别對這兩種方式進行了測試：
1.ALTER DATABASE RENAME GLOBAL_NAME TO [.db_domain];
SQL> select * from global_name;
GLOBAL_NAME
------------------------------------------------------------------------------------------------------------------------------------
MS1.CCB.COM.CN
SQL> alter database rename global_name to "MS2";
Database altered.
SQL> select * from global_name;
GLOBAL_NAME
------------------------------------------------------------------------------------------------------------------------------------
MS2.CCB.COM.CN
可見，沒有生效，檢視10046事件的trace内容，發現在背景是進行了如下操作：
=====================
PARSING IN CURSOR #1 len=43 dep=0 uid=0 ct=35 lid=0 tim=1207805173891065 hv=2712338254 ad='58086b90'
alter database rename global_name to "MS2"
END OF STMT
PARSE #1:c=0,e=2621,p=0,cr=4,cu=0,mis=1,r=0,dep=0,og=4,tim=1207805173891059
BINDS #1:
=====================
PARSING IN CURSOR #2 len=59 dep=1 uid=0 ct=6 lid=0 tim=1207805173891722 hv=3885980964 ad='5825d020'
update props$ set value$ = :1 where name = 'GLOBAL_DB_NAME'
END OF STMT
PARSE #2:c=0,e=401,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=0,tim=1207805173891716
BINDS #2:
bind 0: dty=1 mxl=32(14) mal=00 scl=00 pre=00 acflg=18 oacfl2=1 size=32 ffset=0
bfp=580d84aa bln=32 avl=14 flg=09
value="MS2.CCB.COM.CN"
EXEC #2:c=0,e=1176,p=0,cr=3,cu=2,mis=0,r=1,dep=1,og=4,tim=1207805173893000
XCTEND rlbk=0, rd_only=1
EXEC #1:c=0,e=3345,p=0,cr=3,cu=5,mis=0,r=0,dep=0,og=4,tim=1207805173894474
WAIT #1: nam='log file sync' ela= 2089 p1=253 p2=0 p3=0
WAIT #1: nam='SQL*Net message to client' ela= 2 p1=1650815232 p2=1 p3=0
可以看出，在修改props$表時，并沒有把value修改為MS2,而是仍然修改為MS2.CCB.COM.CN。
2.UPDATE GLOBAL_NAME SET GLOBAL_NAME = '[.db_domain]';
SQL> UPDATE GLOBAL_NAME SET GLOBAL_NAME ='MS2';
1 row updated.
SQL> commit;
Commit complete.
SQL> select * from global_name;
GLOBAL_NAME
--------------------------------------------------------------------------------
MS2
修改成功，此時檢視10046事件的trace内容：
=====================
PARSING IN CURSOR #1 len=41 dep=0 uid=0 ct=6 lid=0 tim=1207805466351466 hv=1935203014 ad='58330e38'
UPDATE GLOBAL_NAME SET GLOBAL_NAME ='MS2'
END OF STMT
PARSE #1:c=10000,e=13060,p=0,cr=11,cu=0,mis=1,r=0,dep=0,og=4,tim=1207805466351458
BINDS #1:
EXEC #1:c=0,e=973,p=0,cr=3,cu=2,mis=0,r=1,dep=0,og=4,tim=1207805466352526
WAIT #1: nam='SQL*Net message to client' ela= 3 p1=1650815232 p2=1 p3=0
*** 2009-03-11 12:33:36.109
WAIT #1: nam='SQL*Net message from client' ela= 18129623 p1=1650815232 p2=1 p3=0
STAT #1 id=1 cnt=0 pid=0 pos=1 bj=0 p='UPDATE (cr=3 r=0 w=0 time=852 us)'
STAT #1 id=2 cnt=1 pid=1 pos=1 bj=101 p='TABLE ACCESS FULL PROPS$ (cr=3 r=0 w=0 time=205 us)'
=====================
修改的是GLOBAL_NAME這個視圖，而這個視圖的定義是：
SQL> select view_name,text from dba_views where view_name='GLOBAL_NAME';
VIEW_NAME TEXT
------------------------------ --------------------------------------------------------------------------------
GLOBAL_NAME select value$ from sys.props$ where name = 'GLOBAL_DB_NAME'
可見，通過update global_name的方法，其實質仍然是修改props$表的value$值，但如果采用alter database的方式，實際執行時會自動加上後面的域名，進而導緻修改不成功。
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轉載于:http://blog.itpub.net/10972173/viewspace-566791/