ORA-00354:, ORA-16014:

ORA-00354:
How to recover from
ORA-00354: corrupt redo log block header
also
ORA-00312: online log 1 thread 1: '/u02/oradata/DEV/redo01.log'
ORA-16038: log 1 sequence# 2530 cannot be archived
ORA-00354: corrupt redo log block header
also

SQL> alter database mount;
SQL> alter database open resetlogs;
SQL> alter database open;

ERROR at line 1:
ORA-16014: log 1 sequence# 2530 not archived, no available destinations
ORA-00312: online log 1 thread 1: '/u02/oradata/DEV/redo01.log'

I have not tested with the database open. I crashed this instance and could not open due to the corrupted redo log. In mount state issue the following commands for your specific redo logs with corruption.

SQL> alter database clear unarchived logfile '/u02/oradata/DEV/redo01.log';
SQL> alter database clear unarchived logfile '/u03/oradata/DEV/redo02.log';
SQL> alter database clear unarchived logfile '/u04/oradata/DEV/redo03.log';
SQL> alter database open;


I restarted to be sure everything was good.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

_disable_logging = TRUE

ORA-00354: corrupt redo log block header
ORA-00353: log corruption near block 39540 change 3193784747 time 01/13/2009 22:08:29
ORA-00312: online log 1 thread 1: '/u02/oradata/DEV/redo01.log'
ORA-16038: log 1 sequence# 2530 cannot be archived

Beware of the hiddden parameter _disable_logging

My goal was to speed up an import of data by disabling archive logging without turning off the Archiver. Of course in hindsight I know now that this was a bad idea and simply puting the database in noarchivelog mode would have been much simpler. But it's always fun to learn new things.

SQL> alter database noarchivelog;

SQL> alter database open;

Once I set the hidden parameter _disable_logging=TRUE, I kicked of the import and pretty quick started recieving alert log errors notifying me of corrupt redo log block headers. My advice - do not use this parameter!

How to recover from
ORA-00354: corrupt redo log block header

Oracle DBA interview questions

How do you really prepare for technical questions you might get during an interview? I try to read as much as I can and review notes on basic questions or other typical interview questions regarding an Oracle DBA. On a recent job interview I was asked the following technical questions. I'll do my best to answer them as well, but if you have an opinion please fell free to chime in.

• How to you recover from block level corruption using RMAN?
• What is DBVerify and how do you use it?
• How do you dump your database to a file?
• How does export differ from datapump?
• How can you export and import an entire schema except for one table using datapump?
• A user has a SQL scripts that used to run in 1 hour and now takes 10 hours. The script has not changed. What could have caused this?
• What is the recommended time frame for gathering statistics in 10g and how is it done?