Understanding what the WITH ROLLBACK IMMEDIATE does

Based on some questions on forums and some of the responses that people have been giving there appears to be done misunderstanding about what the WITH ROLLBACK IMMEDIATE option does when added to the ALTER DATABASE command.  My goal here is to try and clear up at least some of the confusion.

When you run the ALTER DATABASE command without a termination clause (ROLLBACK AFTER, ROLLBACK IMMEDIATE, NO_WAIT) the ALTER DATABASE command will run until the command completes, or until if command is terminated.

The ROLLBACK AFTER command tells the SQL Server to cancel any pending transactions and rollback those transactions after N number of seconds.

PLAIN TEXT

SQL:

1. ALTER DATABASE YourDatabase
2. …
3. WITH ROLLBACK AFTER 30

The ROLLBACK IMMEDIATE command tells the SQL Server that if it can’t complete the command right away, then the other pending transactions should be rolled back.

The NO_WAIT command has the opposite effect as ROLLBACK IMMEDIATE.  If the ALTER DATABASE transaction can’t be completed then that transaction is terminated.

PLAIN TEXT

SQL:

1. ALTER DATABASE YourDatabase
2. …
3. WITH NO_WAIT

Hopefully this helps clear up some of the confusion.

Denny

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Jameslean  |   Sep 24 2009   4:05PM GMT

The NO_WAIT command has the same effect as ROLLBACK IMMEDIATE.

I don't think this is correct. WITH ROLLBACK AFTER | IMMEDIATE specifies when any other transactions in the database should be rolled back, eg when setting the db to single user mode.

NO_WAIT specifies that if the ALTER DATABASE command cannot complete, ie other open transactions exist, then the ALTER command itself should rollback/fail.

 

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Jameslean  |   Sep 24 2009   4:06PM GMT

NB, the first line in my above post is the quote that I don't think is correct!

 

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mrdenny  |   Sep 24 2009   6:26PM GMT

I'm not sure how I managed to get that so wrong. I've updated the blog post so that it's correct.

 

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Fhhdjfhjdhfjhjdfh  |   May 21 2010   10:30AM GMT

HI,

when i run the command

alter database northwind
set multi_user with rollback immediate

the northwind database shows ACCESS denied and tagged as SINGLE USER
i donot understand why it so .can u pls explain .