问题
I have a webservice (asmx) that is running on 2 different servers that sit behind a load balancer. The service is called by multiple clients across our organization, as per my current knowledge, none of the clients use multiple threads.
I'm investigating a production issue where some of the data in a few static variables is clearing or returning null or empty, causing db exceptions and foreign key constraint errors.
Upon investigation, I noticed that the singleton pattern is not implemented correctly, so it's definitely not multi thread safe.
I checked with my team and see if there is any scenario where the service might run under multiple threads but they're all saying no.
I don't know why but I'm still convinced that it is running multiple threads as all the production issues I see align with the multi thread functionality. I can also force these errors when I do a parallel.invoke in my unit test cases, but I cannot find the scenario where it's happening on a day to day basis.
I was wondering if there is any way to go through the IIS logs or anything on the windows servers itself that might clarify this situation whether the service or anything inside it is using multiple threads while it's running.
Is it possible that on each IIS, the service is in its own single thread but when it calls other classes and methods within itself, they start their own thread?
I apologize for not sharing any code yet, just given the sheer amount of code, I didn't get a chance to extract part of it to post it here, I'll need to refactor quite a few things before I can post it here.
Many thanks in advance.
来源：https://stackoverflow.com/questions/57162459/how-to-check-if-a-web-service-is-running-in-multiple-threads-instead-of-a-single