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Återställa backup på databas som används av massa andra users

posted Sep 7, 2009, 12:13 AM by Peter Henell   [ updated Sep 7, 2009, 12:16 AM ]
The best approach for doing this would be to use the ALTER DATABASE
command to set the database to single user mode along with rolling
back any open transactions.  The command looks something like one of
the following.

ALTER DATABASE [Test4] SET SINGLE_USER WITH ROLLBACK IMMEDIATE
OR
ALTER DATABASE [Test4] SET SINGLE_USER WITH ROLLBACK AFTER 30
OR
ALTER DATABASE [Test4] SET SINGLE_USER WITH NO_WAIT

WITH ROLLBACK IMMEDIATE - this option doesn't wait for transactions to
complete it just begins rolling back all open transactions
WITH ROLLBACK AFTER nnn - this option will rollback all open
transactions after waiting nnn seconds for the open transactions to
complete.  In our example we are specifying that the process should
wait 30 seconds before rolling back any open transactions.
WITH NO_WAIT - this option will only set the database to single user
mode if all transactions have been completed.  It waits for a
specified period of time and if the transactions are not complete the
process will fail.  This is the cleanest approach, because it doesn't
rollback any transactions, but it will not always work if there are
open transactions.
Once the database has been put in single user mode, you have exclusive
access to the database and can then do the restore without a problem.

Note: when using the ROLLBACK option you are rolling back any open
transactions that still exist for the database.  The rollback process
should work without issue, but if you have very long running
transactions the rollback process could take a long time, so be aware
of what is running on your systems.  For test and development systems
since you are doing a restore you don't care about the transactions
anyway, so rolling things back should not be an issue, but you still
need to be aware that long running transactions may take some time to
rollback.

Summary
Once the database is in single user mode it is now easy to perform the
restore process.  Here is a sample set of code that puts the database
in single user mode and does the restore.

ALTER DATABASE [Test4] SET SINGLE_USER WITH ROLLBACK IMMEDIATE<br>
<br>
RESTORE DATABASE [Test4]<br>
FROM DISK = 'c:\test4.BAK'<br>
WITH MOVE 'Test4_Data' TO 'c:\data\Test4.mdf',<br>
MOVE 'Test4_Log' TO 'c:\data\Test4_log.ldf'
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