从源库10gR2导出（EXP/IMP）数据到目标库11gR2（开启了连接池）时的错误及解决方法，见下：
--第一次导入：
[oracle@db1 20131226]$ imp 用户/密码@width file=iflashbuy.dmp fromuser=iflashbuy touser=iflashbuytest IGNORE=Y
Import: Release 11.2.0.1.0 - Production on Fri Dec 27 14:46:47 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
IMP-00003: ORACLE error 56605 encountered
ORA-56605: DRCP: Session switching and migration not allowed
IMP-00000: Import terminated unsuccessfully
查看oracle文档说是连接池不支持，需要关闭。
ORA-56605: DRCP: Session switching and migration not allowed
Cause: Application tried to switch or migrate session across connections.
Action: This usage is irrelevant in the Database Resident connection pooling context and is not supported. Release existing session.
--关闭连接池：
SQL> execute dbms_connection_pool.stop_pool;
PL/SQL procedure successfully completed
--再次导入报listener的错误，重启listener后导入还是报同样的错误：
[oracle@db1 20131226]$ imp 用户/密码@width file=iflashbuy.dmp fromuser=iflashbuy touser=iflashbuytest IGNORE=Y
Import: Release 11.2.0.1.0 - Production on Fri Dec 27 14:54:06 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
IMP-00058: ORACLE error 12520 encountered
ORA-12520: TNS:listener could not find available handler for requested type of server
IMP-00000: Import terminated unsuccessfully
--最后尝试不加oracle_sid，导入成功，见下：
[oracle@db1 20131226]$ imp 用户/密码 file=iflashbuy.dmp fromuser=iflashbuy touser=iflashbuytest IGNORE=Y
Import: Release 11.2.0.1.0 - Production on Fri Dec 27 14:58:27 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
Export file created by EXPORT:V10.02.01 via direct path
Warning: the objects were exported by IFLASHBUY, not by you
import done in ZHS16GBK character set and AL16UTF16 NCHAR character set
. . importing table "AREA" 8 rows imported
....................
. . importing table "T_TMP_AREA" 2913 rows imported
. . importing table "T_TMP_SOFTWARE" 25 rows imported
Import terminated successfully without warnings.
为什么有这样的限制不太清楚，10g向10g、11g向11g导数据是不会有这样的限制。