RE: OCP Question
Date: Wed, 16 Dec 2009 15:06:10 -0500
Hope this helps.
This is an extract from Oracle Manual:
Checking for Missing or Extra Files
After creating a new control file and using it to open the database, check the alert log to see if the database has detected inconsistencies between the data dictionary and the control file, such as a datafile in the data dictionary includes that the control file does not list.
If a datafile exists in the data dictionary but not in the new control file, the database creates a placeholder entry in the control file under the name MISSINGnnnn, where nnnn is the file number in decimal. MISSINGnnnn is flagged in the control file as being offline and requiring media recovery.
If the actual datafile corresponding to MISSINGnnnn is read-only or offline normal, then you can make the datafile accessible by renaming MISSINGnnnn to the name of the actual datafile. If MISSINGnnnn corresponds to a datafile that was not read-only or offline normal, then you cannot use the rename operation to make the datafile accessible, because the datafile requires media recovery that is precluded by the results of RESETLOGS. In this case, you must drop the tablespace containing the datafile.
Conversely, if a datafile listed in the control file is not present in the data dictionary, then the database removes references to it from the new control file. In both cases, the database includes an explanatory message in the alert log to let you know what was found.
From: Bill Zakrzewski [mailto:bill_at_intactus.com] Sent: Wednesday, December 16, 2009 2:58 PM To: Oracle-L_at_freelists.org
Subject: OCP Question
I took the Oracle 10g OCP exam and one question in the exam was something I have not come across in several years working with Oracle. I searched google, but only found someone has had this happen, but they didn't understand why - it was during a database cloning process.
It went something like - You rebuild your controlfile and open your database and discover several datafiles have been renamed to /somepath/MISSING##### (where ##### is a 5-digit number).
What might that signify?
A. Those are corrupt files? B. Those are read-only tablespace files? C. ..... D. ..... E. .....
I don't remember the five choices, but does anyone know why Oracle would rename datafiles to .....MISSING#####.