今天检查数据库中的备份输出脚本时，发现RMAN备份出现了错误。
这一篇主要描述问题的现象。
错误信息如下：
bash-3.00$ more /data/backup/backup_tradedb_090523.out
Script. /data/backup/backup_tradedb.sh
==== started on Sat May 23 23:00:00 CST 2009 ====
RMAN: /opt/oracle/product/10.2/database/bin/rman
ORACLE_SID: tradedb1
ORACLE_HOME: /opt/oracle/product/10.2/database
Recovery Manager: Release 10.2.0.3.0 - Production on Sat May 23 23:00:01 2009
Copyright (c) 1982, 2005, Oracle. All rights reserved.
RMAN-06900: WARNING: unable to generate V$RMAN_STATUS or V$RMAN_OUTPUT row
RMAN-06901: WARNING: disabling update of the V$RMAN_STATUS and V$RMAN_OUTPUT rows
ORACLE error from target database:
ORA-03113: end-of-file on communication channel
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00554: initialization of internal recovery manager package failed
RMAN-06003: ORACLE error from target database:
ORA-03114: not connected to ORACLE
Script. /data/backup/backup_tradedb.sh
==== ended in error on Sat May 23 23:22:34 CST 2009 ====
这个错误信息以前还真的没有碰到过，出现了ORA-3113错误，还有两个告警信息，初步怀疑可能与网络不稳定有关，尝试重新启动后台备份，如果可以顺利运行，说明这个问题可能是瞬时网络不稳定造成的。
bash-3.00$ more /data/backup/backup_tradedb_090525.out
Script. bash
==== started on Mon May 25 14:34:14 CST 2009 ====
RMAN: /opt/oracle/product/10.2/database/bin/rman
ORACLE_SID: tradedb1
ORACLE_HOME: /opt/oracle/product/10.2/database
恢复管理器: Release 10.2.0.3.0 - Production on星期一5月25 14:34:15 2009
Copyright (c) 1982, 2005, Oracle. All rights reserved.
RMAN-06900:警告:无法生成V$RMAN_STATUS或V$RMAN_OUTPUT行
RMAN-06901:警告:禁止更新V$RMAN_STATUS和V$RMAN_OUTPUT行
来自目标数据库的ORACLE错误:
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00554:内部恢复管理器程序包初始化失败
RMAN-06003:来自目标数据库的ORACLE错误:
ORA-03114:未连接到ORALCE
Script. bash
==== ended in error on Mon May 25 14:56:54 CST 2009 ====
在后台运行备份后，很快输出脚本中就显示了错误信息，和前一次错误信息略有区别，这次没有ORA-3113错误了。看来问题是可以重现的，尝试直接RMAN连接：
bash-3.00$ rman target /
恢复管理器: Release 10.2.0.3.0 - Production on星期一5月25 15:02:51 2009
Copyright (c) 1982, 2005, Oracle. All rights reserved.
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RMAN连接数据库的操作被挂起。在等待RMAN相应的时候，查询了一下alert文件，检查备份启动时刻是否有对应的错误信息，结果果然有对应的错误：
Sat May 23 17:16:43 2009
GES: Potential blocker (pid=17895) on resource WF-00000046-00000000;
enqueue info in file /opt/oracle/admin/tradedb/bdump/tradedb1_lmd0_7210.trc and DIAG trace file
Sat May 23 21:28:36 2009
GES: Potential blocker (pid=15807) on resource TM-00002391-00000000;
enqueue info in file /opt/oracle/admin/tradedb/bdump/tradedb1_lmd0_7210.trc and DIAG trace file
Sat May 23 23:15:04 2009
GES: Potential blocker (pid=21881) on resource CF-00000000-00000000;
enqueue info in file /opt/oracle/admin/tradedb/bdump/tradedb1_lmd0_7210.trc and DIAG trace file