https://blog.aabech.no/ Ramblings about Umbraco, .net and JavaScript development. With a sprinkle of other stuff. Articulate, blogging built on Umbraco 1117 https://blog.aabech.no/archive/potential-freeze-with-umbraco-and-signalr/ <p>I cloned the Umbraco 7.7 dev branch today to prepare a demo for my colleagues next week. SignalR has been bundled with Umbraco, and guess what - problems I've had before hit me again. It just freezes on boot, specifically at the app.MapSignalR call in the Owin startup.</p> <p>Turns out, the HQ guys have already been down this road and helped fix a really really weird bug with it. Read <a href="https://github.com/SignalR/SignalR/issues/3414">the issue</a> and <a href="https://www.zpqrtbnk.net/posts/appdomains-threads-cultureinfos-and-paracetamol">Stephane's post</a>, it's quite interesting. But this was not the issue that hit me, even tho it's quite similar in behavior.</p> <p>I've actually been down this road before myself. I recalled having had similar problems. I didn't dive into it back then, I just gave up and threw SignalR out. I'd like to say I have just as deep an analysis as Stephane has in his post, but I'm just not as good. :) In any case, it's something to do with the performance counters reading a registry key.</p> <p>The code is somewhere within <code>PerformanceCounter.NextSample()</code>. My debugging symbols fu is not strong enough to get everything right there, but it's somewhere in the <code>PerformanceCounterLib</code> and has something to do with a <code>RegistryKey</code> being read. I had it in the stacktrace, but I'm sorry to say I didn't record it.</p> <p>Popping the registry editor, I find it already focused on a registry key called SignalR. I'm guessing I haven't had it open since I gave up the last time. Again, sorry for not having deeper knowledge here. You might have a gazillion keys called SignalR-something.vstemplate. These are safe, but the one only named SignalR is our suspect. I impatiently went ahead and deleted it, and now everything works.</p> <p>So I'm stuck trying to provide any deeper knowledge, and I was stupid enough not to record the key name before I threw it out. Although, I'm pretty sure it is from the <a href="http://www.asp.net/signalr/overview/performance/signalr-performance#perfcounters">SignalR performance counters</a>, and that the key in question is <code>HKLM\System\CurrentControlSet\Services\SignalR\Performance</code>. I threw the whole <code>SignalR</code> key out.</p> <p>If I gain any deeper knowledge, I'll update this post. Otherwise, at least you know that deleting that key may save your day. :)</p> Fri, 23 Jun 2017 22:16:38 Z 2017-06-23T22:16:38Z