At certain times during the week while I'm testing my Mobile Services app I get a 503 error (Service Unavailable). It happens whether I try to call the app from localhost or live on my Azure Website. It hangs around for 10-15 minutes and then goes away on its own. It doesn't seem to be caused by anything in particular that I am doing (i.e. I have not updated any code). The 503 error occurs when I'm trying to call one of my custom APIs in my Mobile Services account. A few of the requests make it through (strangely enough) but the majority return a 503 error.
I've seen that someone had a very similar problem here (Why does Azure give me an intermittent Error 503. The service is unavailable?) without an acceptable resolution.
I am using the free version of Mobile Services but I should be no where near pushing the limits of what the free version can handle; I am the sole user of the app right now.
It will soon be time to make the service live and I'm shuddering at the thought of support calls that will come in during one of these funky states the service gets into. Any help in debugging the problem would be greatly appreciated.
EDIT:
I've narrowed this down to a database problem. I have one main query (sproc) that I use to feed data to the UI. I noticed that when I get the 503 errors the query takes about 13 seconds (when run in SSMS). When things are running "normally", the query takes less than a second.
This doesn't solve my problem though, in fact it makes it more perplexing because I am using the Business Edition of Windows Azure SQL Database and there shouldn't be a 13 second fluctuation in execution time!
This problem seems to happen randomly. Is there some kind of caching in SQL Server that could explain this? Maybe my query really does take 13 seconds to execute and the caching superficially speeds it up.
