Code Sample | StreamInsightMarch 16, 2014 12:31 PM
Here’s all of the materials from the presentation that I did at the Houston .NET User’s Group on March 13. Some of the things that I updated from the version for Baton Rouge Sql Saturday include:
Lock around active requests HashSet: Added a lock block around adding and removing items from the _activeRequest HashSet. Since the HashSet isn’t thread-safe and our source is very highly multi-threaded, we need to make sure that operations that modify the internal array are thread-safe. This eliminated some random “IndexOutOfBoundsException” in the source that would halt StreamInsight process.
Checks in StandardDeviation UDA: Added checks for the number of values as well as the result. If the number of values in the set for the standard deviation is less than one, the standard deviation is always 0. Also, after the calculation, there’s an additional check on the result to make sure it’s not NaN. This eliminated some random exceptions in the queries that were calculating the standard deviation that would halt the StreamInsight process.
Both cases highlight the need to make sure that your custom code running in StreamInsight is tight and solid. They were pretty difficult to track down as well … both would happen randomly. Intellitrace was absolutely essential to identifying and resolving the issues. After fixing them, I was able to run for hours without a problem.
Notes to reproducing the demo:
I’m not including the site that I used when running the demo. You can get this from the NopCommerce site on CodePlex. I used the out-of-the-box site with sample data. Keep in mind that the module used for the demo forces some of the requests to take 3 seconds – these are our “Bad Actors” – so it’s in no way representative of the performance of nopCommerce. You’ll need to set it up on a local site on port 81 if you want to use the Visual Studio load tests. From there, you need to copy the WebSiteMonitor.Contracts and WebSiteMonitor.Module assemblies into the \bin folder of the site and add the following into the web.config:
- Under system.WebServer, add the module
- Under system.ServiceModel, add the WCF configuration
- <serviceHostingEnvironmentaspNetCompatibilityEnabled="true"multipleSiteBindingsEnabled="true" />
- <bindingname="streamedNetTcpBinding"transferMode="Streamed" />
- name="Client" />
You may (probably will) need to specify the StreamInsight 2.1 instance name that you are using. This is in the app.config for the WebSiteMonitor.WinForms project under “applicationSettings”. The setting name is “StreamInsightInstance” (very creative, I know).
You’ll want to run the client app “As Administrator” or reserve the URLs for non-administrator users and accounts. If you are running from Visual Studio, run Visual Studio as Administrator. I tend to run as Administrator when testing and running the demo. In the real-world, you’d reserve the URLs. The TestWebSite project in the solution is a “New Web Site” template from Visual Studio and helps make sure that everything is set up properly. It also has the configuration settings.