Tagged: debugging


Hunting .NET memory leaks with Windbg

Recently a client called me about an issue where one of their production servers would run out of memory, every other week. The application in question was a .NET Framework 4.5 Windows service, that runs in an Azure VM, and ever so often it would become unstable and start causing trouble. I have previously helped this client set up an ELK stack, so it was quick for me to go into Kibana, look at metricbeat data, and see that their server indeed slowly was eating up memory over time. And every time the application was restarted, the memory would return to normal, and slowly creep upwards again. As you can clearly see, the application uses gradually more and more memory over time. Every time the line drops, was a restart of the server, where it went back to normal operation at about 150 MB. When they initially called me, they had just restarted the application, so I had no real practical way of finding out what caused the memory right there and then, but I logged on to the server and created a memory dump for the recently restarted application, so I would have a baseline for how it looks during normal operation. Creating a memory dump file The best way to figure out what is causing a memory leak, is to analyse the memory of the running application. To do that, we need to make a “memory dump”, and thankfully on Windows this is straight forward. Open Task Manager. Go to the Processes(older) or...

Software consultant 1

10 tips and tricks for solving software problems

As software consultants, we are often faced with bugs or problems the client cannot fix themselves. We are expected to quickly figure out the problem, and propose or implement a solution. Through my career I have developed a sort of mindset to get to the bottom of issues without wasting time hunting deadends or non-issues, and deliver results and value more efficiently. Here is my list of 10 tips for how I go about solving software problems 1. Focus A common problem I saw in myself, and I see very often in software developers, is a lack of focus. If you are trying to solve too many issues at once, you will probably fail at all of them. The first thing you must do, is figure out what you are actually trying to solve, and then stay on target. Usually my clients, have some sort description of what should be happening, and what isn’t happening. The description of the issues are often vague, but can be boiled down to tangible issues. As developers, we have a tendency to hunt any bug we find. If for example you are dealing with communication issues between two services, it might not be relevant to your current task, to start debugging the datalayer or refactoring a calculation algorithm. A side effect to lack of focus, is that your git history becomes unclear and kind of a mess. All of a sudden you have two or more half-done fixes staged, which means that either you can’t commit the first fix,...