创建mview时，varchar2,char字段长度翻番？

在新安装的oracle10做mview时，所有涉及varchar2的字段长度都翻番，怎么回事，新手请教？
create materialized view MV_ACC_TRANS_NOTIFY
refresh force on demand with rowid
as
select * from acc_trans_notify@ossdb
where region_id='L';
oracle10上看的
SQL> desc MV_ACC_TRANS_NOTIFY;
Name             Type         Nullable Default Comments 
---------------- ------------ -------- ------- -------- 
TRANS_ID         NUMBER(15)                             
SUBSCRIPTION_ID  NUMBER(9)                              
SVC_TYPE         NUMBER(4)                              
ACCOUNT_ID       NUMBER(9)                              
REGION_ID        CHAR(2)                                
SUBJECT_ID       NUMBER(9)                              
START_RULE_ID    NUMBER(2)                              
START_VALUE      VARCHAR2(20)                           
AMOUNT_RULE_ID   NUMBER(2)                              
AMOUNT_VALUE     VARCHAR2(20)                           
STATUS           NUMBER(1)                              
CREATE_TIME      DATE         Y                         
EFFECT_DATE      DATE                                   
EXPIRE_DATE      DATE                                   
EFFECT_DAYS      NUMBER(4)                              
LAST_TRANS_MONTH CHAR(12)                               
TRANS_TYPE       NUMBER(2)                              
OP_REGION_ID     CHAR(2)                                
OPERATOR_ID      VARCHAR2(24)                           
OP_COUNTY_ID     CHAR(6)                                
OFFICE_ID        CHAR(14)                               
PAY_CHANNEL      NUMBER(2)                              
BUSINESS_CODE    NUMBER(8)  这个是oracle9上的
SQL> desc ACC_TRANS_NOTIFY;
Name             Type         Nullable Default Comments 
---------------- ------------ -------- ------- -------- 
TRANS_ID         NUMBER(15)                             
SUBSCRIPTION_ID  NUMBER(9)                              
SVC_TYPE         NUMBER(4)                              
ACCOUNT_ID       NUMBER(9)                              
REGION_ID        CHAR(1)                                
SUBJECT_ID       NUMBER(9)                              
START_RULE_ID    NUMBER(2)                              
START_VALUE      VARCHAR2(10)                           
AMOUNT_RULE_ID   NUMBER(2)                              
AMOUNT_VALUE     VARCHAR2(10)                           
STATUS           NUMBER(1)                              
CREATE_TIME      DATE         Y                         
EFFECT_DATE      DATE                                   
EXPIRE_DATE      DATE                                   
EFFECT_DAYS      NUMBER(4)                              
LAST_TRANS_MONTH CHAR(6)                                
TRANS_TYPE       NUMBER(2)                              
OP_REGION_ID     CHAR(1)                                
OPERATOR_ID      VARCHAR2(12)                           
OP_COUNTY_ID     CHAR(3)                                
OFFICE_ID        CHAR(7)                                
PAY_CHANNEL      NUMBER(2)                              
BUSINESS_CODE    NUMBER(8)  
oracle10版本
SQL> select * from v$version;BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bi
PL/SQL Release 10.2.0.1.0 - Production
CORE        10.2.0.1.0        Production
TNS for 64-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Productiondblink的数据库是oracle9的
SQL> select * from v$version
  2  ;BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.2.0.4.0 - 64bit Production
PL/SQL Release 9.2.0.4.0 - Production
CORE        9.2.0.3.0        Production
TNS for IBM/AIX RISC System/6000: Version 9.2.0.4.0 - Production
NLSRTL Version 9.2.0.4.0 - Production