In helping out with a project involving ASP.NET 2.0's cache sync feature, which has best performance when built on SQL Server 2005's Query Notifications, I was asked if there was a way to "pre-provision" the queue, service, and stored procedure that cache sync needs. The concern was that the connection string to start up the listener (in Application.OnStart()) used the same security principal as the remainder of the application. That is, the app data access and listener start connection strings were both

"server=myserver;integrated security=sspi;database=mydb".

This meant that the entire application had create queue, create service, and create procedure privilege. That's too much privilege. Using a separate SQL login for SqlDependency.Start() was not an option.

ADO.NET's SqlDependency has an override for the static Start method that takes the name of a pre-provisioned queue. This can be combined with use of the constructor of SqlDependency that uses an Options parameter. In my test, the queue name had to be a one-part SQL identifier; a two-part name (schema.object) didn't seem to work. So the queue, service, and procedure must live in the SQL principal's default schema. The options parameter is a string that names the Service and Database (Broker Instance) that the depdendency should use. The options string would look like this:

"service=myservice;local database=mydb" or
"service=myservice;broker instance={GUID}" //where GUID is the Service Broker GUID.

As far as a stored procedure to do the same type of processing that SqlDepedency's listener does, you can base your procedure on the one SqlDependency dynamically generates, changing the name of the queue and service, of course.

Unfortunately, ASP.NET's SqlCacheDependency doesn't allow the options string to be specified. And the override of SqlDepedency.Start() doesn't work without the corresponding options on SqlDependency. So the only way to use a preconfigured service, queue, and is to build you own cache, using the ASP.NET Cache class as a "template". It's not as simple as being able to use the OutputCache directive on the Page class, made things OK as far as the security folks concerns.

Perhaps ASP.NET will support this in future, or there's a workaround that I hadn't thought of (and I did go as far as to read the code for SqlCacheDependency). I'll have more to say about query notifications at the upcoming SQLskills scale-out events. It's quite an interesting area. If you have lots of read-mostly lookup tables, its well worth the time.