The alert for ‘time behind’ has been raised. The current value of ‘xyz’ surpasses the threshold ‘abc’.

This is the strange error message that I encountered from a mirroring principal server on which an alert is set to report to DBA team if error number “32040” is detected.  The official Microsoft description of this error message can be found here at Microsoft’s website. And usually this error is reported only when unsent transactions are piling up at the principal box. However, the mirroring monitor showed perfect 0KB of “unsent log” and 00:00:00 of “oldest unsent transactions”.

To resolve this issue, I used the “pause and restart mirroring” approach that somebody mentioned here at SQLServerCentral’s forum. The exact scripts are as follows:

[sourcecode language=”sql”]
ALTER DATABASE [DBNAME] SET PARTNER SUSPEND
GO
ALTER DATABASE [DBNAME] SET PARTNER RESUME
GO
[/sourcecode]