Hi Friends,

SQL Server Consistency errors Failed rollback is when the rollback process fails for a user transaction which is no doubt a critical problem, SQL engine reacts by taking the user database offline and restarting it. This means, recovery to run again on the database with an expectation that rolling back the transaction that couldn’t be rollback online. Most of the cases this approach is successful as in some cases the online rollback could be an interim problem that may not reoccur when transactions are rolled back log on the disk. SQL Server does attempt to isolate the issue i.e. only databases with failed rollback are affected. SQL engine makes sure that in that process other databases that are present on the instance not impacted whatsoever. In case this happens to tempdb, as understood server shuts down as there is no other way to recover tempdb which is a critical shared resource on the SQL instance. As we discuss failed rollback, it is good to know few error codes such as 3313, 3314, 3414 and 3456 that are discussed here on MSDN.

And when your database is corrupt, it is possible that SQL engine will run into access violation issues as there is no validation check for each bit on the database pages at each place in code which may result in performance issues. Access violation may occur many different places due to DB corruption and most likely you get a stack dump generated in such cases. It is recommended to run DBCC CHECKDB for all the databases if you keep receiving such errors frequently and find out if there are metadata corruptions etc. It is equally important to get the stack dump analyzed properly to isolate the issue and ensure data safety.



Kanchan Bhattacharyya

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