從源庫10gR2導出（EXP/IMP）數據到目標庫11gR2（開啓了連接池）時的錯誤及解決方法，見下：
--第一次導入：
[oracle@db1 20131226]$ imp 用戶/密碼@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文檔說是連接池不支持，需要關閉。
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.
--關閉連接池：
SQL> execute dbms_connection_pool.stop_pool;
PL/SQL procedure successfully completed
--再次導入報listener的錯誤，重啓listener後導入還是報同樣的錯誤：
[oracle@db1 20131226]$ imp 用戶/密碼@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
--最後嘗試不加oracle_sid，導入成功，見下：
[oracle@db1 20131226]$ imp 用戶/密碼 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.
爲什麼有這樣的限制不太清楚，10g向10g、11g向11g導數據是不會有這樣的限制。