检查数据库日志文件，发现在执行expdp操作前后都有修改service_names操作
1.数据库版本信息

SQL>  select instance_name from v$instance;
INSTANCE_NAME
----------------
ora9i2
SQL>  select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux IA64: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
spfile文件中，无service_names配置，证明都是在修改MEMORY中。

2.alert日志内容

Thu Jan  5 01:10:06 2012
The value (30) of MAXTRANS parameter ignored.
Thu Jan  5 01:10:09 2012
ALTER SYSTEM SET service_names='ora9i','SYS$SYS.KUPC$C_2_20120105011007.ORA9I' SCOPE=MEMORY SID='ora9i2';
Thu Jan  5 01:10:09 2012
ALTER SYSTEM SET service_names='SYS$SYS.KUPC$C_2_20120105011007.ORA9I','ora9i','SYS$SYS.KUPC$S_2_20120105011007.ORA9I' SCOPE=MEMORY SID='ora9i2';
kupprdp: master process DM00 started with pid=305, OS id=9526
         to execute - SYS.KUPM$MCP.MAIN('SYS_EXPORT_TABLE_05', 'VAS', 'KUPC$C_2_20120105011007', 'KUPC$S_2_20120105011007', 0);
kupprdp: worker process DW01 started with worker id=1, pid=307, OS id=9641
         to execute - SYS.KUPW$WORKER.MAIN('SYS_EXPORT_TABLE_05', 'VAS');
kupprdp: worker process DW02 started with worker id=2, pid=308, OS id=9964
         to execute - SYS.KUPW$WORKER.MAIN('SYS_EXPORT_TABLE_05', 'VAS');
kupprdp: worker process DW03 started with worker id=3, pid=309, OS id=9966
         to execute - SYS.KUPW$WORKER.MAIN('SYS_EXPORT_TABLE_05', 'VAS');
kupprdp: worker process DW04 started with worker id=4, pid=310, OS id=9968
         to execute - SYS.KUPW$WORKER.MAIN('SYS_EXPORT_TABLE_05', 'VAS');
Thu Jan  5 01:13:15 2012
ALTER SYSTEM SET service_names='SYS$SYS.KUPC$S_2_20120105011007.ORA9I','ora9i' SCOPE=MEMORY SID='ora9i2';
Thu Jan  5 01:13:16 2012
ALTER SYSTEM SET service_names='ora9i' SCOPE=MEMORY SID='ora9i2';

3.MOS解决信息[ID 1269319.1]

Depending on the version of your database, Patch:8513146 may exist.
As of Nov. 25th 2010, this patch exists for:
- 10.2.0.4 / IBM AIX on POWER Systems (64-bit)
- 10.2.0.4.3 / Linux x86-64
- 10.2.0.5 / Linux x86 and Linux x86-64