重新将数据库注册到RMAN Catalog时偶遇ORA-02291错误之探查
转载学习，文章出自：http://blog.itpub.net/519536/viewspace-696656/
使用“unregister database”命令可以取消数据库实例到RMAN Catalog的注册。但是，当需要重新完成注册时需要注意，一定要先退出RMAN环境然后再重新登录完成注册，否则将有可能遭遇“ORA-02291: integrity constraint (RMAN_CATALOG.RLH_F1) violated - parent key not found”这个报错。将这个问题的现象及处理方法整理如下。
1.问题现象
1）将secgc实例注册到secdb实例的RMAN Catalog
secgc@secdb1 /home/oracle$ rman target sys/oracle1@secgc catalog rman_catalog/rman_catalog@secdb
Recovery Manager: Release 10.2.0.1.0 - Production on Sun May 29 21:48:45 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: SECGC (DBID=2970158546)
connected to recovery catalog database
RMAN> register database;
database registered in recovery catalog
starting full resync of recovery catalog
full resync complete
2）确认RMAN Catalog数据库中注册的信息
rman_catalog@secdb> col name for a6
rman_catalog@secdb> select * from rc_database;
DB_KEY DBINC_KEY DBID NAME RESETLOGS_CHANGE# RESETLOGS
---------- ---------- ---------- ------ ----------------- ---------
1 2 2970158546 SECGC 1 25-MAY-11
OK，测试secdb实例已经成功注册到RMAN Catalog中。
3）使用“unregister database”命令取消注册并重新注册
（1）取消注册
RMAN> unregister database;
database name is "SECGC" and DBID is 2970158546
Do you really want to unregister the database (enter YES or NO)? yes
database unregistered from the recovery catalog
（2）查看rc_database信息
rman_catalog@secdb> select * from rc_database;
no rows selected
此时显示已经成功取消注册。
（3）未退出RMAN环境情况下再次进行注册
RMAN> register database;
database registered in recovery catalog
starting full resync of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03008: error while performing automatic resync of recovery catalog
ORA-02291: integrity constraint (RMAN_CATALOG.RLH_F1) violated - parent key not found
问题出现了，此时报出了一个非常诡异的错误：“ORA-02291: integrity constraint (RMAN_CATALOG.RLH_F1) violated - parent key not found”。
如不退出RMAN环境再次执行注册命令会收到如下错误。
RMAN> register database;
starting full resync of recovery catalog
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of register command at 05/29/2011 21:52:55
RMAN-03014: implicit resync of recovery catalog failed
RMAN-03009: failure of full resync command on default channel at 05/29/2011 21:52:55
ORA-02291: integrity constraint (RMAN_CATALOG.RLH_F1) violated - parent key not found
退出RMAN环境重新进入再次注册，会收到如下报错。
RMAN> exit
Recovery Manager complete.
secgc@secdb1 /home/oracle$ rman target sys/oracle1@secgc catalog rman_catalog/rman_catalog@secdb
Recovery Manager: Release 10.2.0.1.0 - Production on Sun May 29 21:53:19 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: SECGC (DBID=2970158546)
connected to recovery catalog database
RMAN> register database;
starting full resync of recovery catalog
full resync complete
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of register command on default channel at 05/29/2011 21:53:25
RMAN-20002: target database already registered in recovery catalog
与此同时，rc_database视图中再次出现secdb的注册信息。
rman_catalog@secdb> select * from rc_database;
DB_KEY DBINC_KEY DBID NAME RESETLOGS_CHANGE# RESETLOGS
---------- ---------- ---------- ------ ----------------- ---------
55 56 2970158546 SECGC 1 25-MAY-11
以上便是使用“unregister database”命令取消注册后再次注册时遇到的问题现象。
2.问题分析及探查过程
报错涉及到的约束是一个外键参照约束，RLH表的DBINC_KEY列参照引用DBINC表的DBINC列。该约束的创建脚本如下。
ALTER TABLE RMAN_CATALOG.RLH ADD (
CONSTRAINT RLH_F1
FOREIGN KEY (DBINC_KEY)
REFERENCES RMAN_CATALOG.DBINC (DBINC_KEY)
ON DELETE CASCADE);
可以跟踪一下这个报错过程：
1）当使用“unregister database”命令取消注册时，可以观察到DBINC表和RLH表的内容都会被清空。
若对这个过程进行trace跟踪，可以观察到在注册的过程中是按照如下顺序进行初始化表数据的。
INSERT INTO DB(DB_KEY, DB_ID)
INSERT INTO DBINC (DBINC_KEY, DB_KEY, DB_NAME, RESET_SCN, RESET_TIME)
INSERT INTO CKP (CKP_KEY, CKP_SCN, CKP_CF_SEQ, CF_CREATE_TIME, CKP_TIME,
INSERT INTO NODE(DB_UNIQUE_NAME, DB_KEY, HIGH_CONF_RECID, FORCE_RESYNC2CF,
INSERT INTO TS (DBINC_KEY, TS#, TS_NAME, CREATE_SCN, CREATE_TIME,
INSERT INTO TSATT(DBINC_KEY, TS#, CREATE_SCN, START_CKP_KEY, RBS_COUNT)
INSERT INTO DF(DBINC_KEY, FILE#, CREATE_SCN, CREATE_TIME, TS#, TS_CREATE_SCN,
INSERT INTO DFATT(DBINC_KEY, FILE#, CREATE_SCN, START_CKP_KEY, FNAME, BLOCKS)
INSERT INTO TF(DBINC_KEY, FILE#, CREATE_SCN, CREATE_TIME, TS#, TS_CREATE_SCN,
INSERT INTO TFATT(DBINC_KEY, FILE#, CREATE_SCN, START_CKP_KEY, FNAME, BLOCKS,
INSERT INTO RT (DBINC_KEY, THREAD#, SEQUENCE#, ENABLE_SCN, ENABLE_TIME,
INSERT INTO ORL (DBINC_KEY, THREAD#, GROUP#, FNAME)
INSERT INTO RSR (RSR_KEY, DBINC_KEY, RSR_RECID, RSR_STAMP, RSR_PKEY,
INSERT INTO ROUT (DB_KEY, RSR_KEY, ROUT_SKEY, ROUT_RECID, ROUT_STAMP,
INSERT INTO RLH( RLH_KEY, DBINC_KEY, RLH_RECID, RLH_STAMP, THREAD#, SEQUENCE#,
2）未退出RMAN环境操作再次注册时，可以观察到此时子表RLH内容为空，原因是找不到父表中的记录，但此时父表DBINC中已经成功写入数据。
3）此时若不退出RMAN环境重新登录，反复进行注册都不会成功
4）在未退出RMAN环境时如果操作取消注册可以成功，对应DBINC表中的记录也会被清空。
5）退出RMAN环境重新登录后再次尝试注册，成功！
6）可以解决问题的重新注册过程如下。
RMAN> unregister database;
database name is "SECGC" and DBID is 2970158546
Do you really want to unregister the database (enter YES or NO)? yes
database unregistered from the recovery catalog
RMAN> exit
Recovery Manager complete.
secgc@secdb1 /home/oracle$ rman target sys/oracle1@secgc catalog rman_catalog/rman_catalog@secdb
Recovery Manager: Release 10.2.0.1.0 - Production on Sun May 29 21:54:20 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
connected to target database: SECGC (DBID=2970158546)
connected to recovery catalog database
RMAN> register database;
database registered in recovery catalog
starting full resync of recovery catalog
full resync complete
按照这个跟踪过程，大家是不是已经有了问题的答案。没错，这是一起由于操作不规范导致的报错。我们应该在每次完成取消注册后退出RMAN环境，重新登录后进行注册！
4.小结
本文给出了一起因操作不规范导致数据库无法重新注册到RMAN Catalog问题的探查过程。
Good luck.
secooler
11.05.29
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