ORA-00600 [2662] Error resolution process

Error | process | resolution
ORA-00600 [2662] Error resolution process

Database version: 7.3.2



Background:

Client side of the database suddenly a current log file is broken, causing the database to crash, then the field Engineer uses _allow_resetlogs_corruption = True This implied parameter, did not fully restore after forced to open the database. However, when the database was opened, it was found that only users connected with the internal, the other user connection errors, the error message is as follows:

Ora-00600:internal error code, arguments: [2662], [0], [431267936], [0], [431273216], [0], [], []

Can not query any application of the table, applications can not use, so want to try the whole library of exp out and then back to the imp into the library, the results found that exp data is not successful, but also reported the same ORA-600 error, the user at that time no backup of the data, can only find a way to open the database, export data.



Processing process:

Check the 600 error-generated trace file first:

Session ID: (7.15) 2004.11.23.23.28.16.824

Ksedmp:internal or fatal error

Ora-00600:internal error code, arguments: [2662], [0], [431267754], [0], [431272752], [0], [], []

Current SQL statement for this session:

SELECT * from "WHSB". " SB_BSBF "

The information is limited, only to see a serious internal error, the rest is the memory stack of a heap of information, and then looked up the error of the specific relevant information.

ORA-600 [2662] "block SCN is ahead the current SCN", which indicates that the SCN of the data blocks of the present database is earlier than the current SCN, primarily compared to the dependent SCN stored in the UGA variable, if the current SCN is less than it, The database will produce this ORA-600 [2662] error. This error has a total of five parameters, representing different meanings, respectively.

ORA-600 [2662] [A] [b] [C] [d] [E]

ARG [A] current SCN WRAP

ARG [b] current SCN BASE

ARG [C] dependent SCN WRAP

ARG [d] dependent SCN BASE

ARG [E] Where present this is the DBA where the dependent SCN came.

We analyze the hint in the error, its parameter b=431267754,d=431272752, indicating that the current SCN is indeed less than dependent SCN, so this 600 error is generated.

By looking through the documentation, you find that this error occurs mainly in the following reasons:

L Resetlogs Open the database after using the suppressed parameter _allow_resetlogs_corruption

L hardware error causes database to write control files and redo log files

L Wrong part of the recovery database

L recovered the control file but did not use the Recover database using Backup controlfile for recovery

L The _disable_logging suppressed parameters are set after the database crash

L DLM Problems in parallel server environment

Careful contrast, found that the problem may be due to the first, because the set _allow_resetlogs_corruption this implied parameters, although the mandatory open the database, but the database itself has corruption, there are still serious problems.

The idea is to use the ADJUST_SCN event to adjust the current SCN to greater than the dependent SCN, and then to ensure that the database can be exported throughout the library, and then rebuild the database import data.

Use internal user login database, connect other users, or failure to complain, execute:

Alter session SET Events ' IMMEDIATE trace name ADJUST_SCN level 1 ';

Then try to connect to another user and the connection is successful.

Finally exp the entire database, rebuild the database and import data, the entire database to restore success!



Through this example, we can see, as far as possible not to use those suppressed parameters, these parameters are not recommended by Oracle, nor omnipotent! If you use some of the remaining problems, if you do not want to use, it is recommended that the use of exp/imp reconstruction to build a database.