What is the exact role of “AspNet_SqlCacheTablesForChangeNotification”

Question

We have a .NET 4.5 Azure Webrole with Azure (colocated) Caching enabled. We use Entity Framework 5.0 talking to an Azure SQL database.

We did some cleanup on our staging/testing and I noticed that the entity framework edmx file complains that

Entity type 'AspNet_SqlCacheTablesForChangeNotification' is not mapped.

We had also briefly experimented with SQL Sync. We don't know if it's SQL Sync or Azure caching that added that table (and any other elements?) to our database

What installs and uses AspNet_SqlCacheTablesForChangeNotification ? Is it safe to remove it? Finally, any extra items that ride along with that table that we should cleanup?

Answer 1

See this article by Scott Hansleman on setting up SQL Server Cache Dependency.

This is set up using the aspnet_regsql.exe tool that comes with .Net

You can disable this using aspnet_regsql -S localhost -U sa -P wrox -d Northwind -dd however I am not sure if this removes the associated configuration tables (Worth a shot). The tool may not work with SQL Azure in which case you may have to manually remove the table.

It's worth checking your web.config is not set up to expect Cache Dependencies by checking for this:

<system.web>
  <caching>
     <sqlCacheDependency enabled="true">
        <databases>
           <add name="Northwind" connectionStringName="AppConnectionString1" 
            pollTime="500" />
        </databases>
     </sqlCacheDependency>
  </caching>
</system.web>