BlogEngine.NET memory leak fix

My pride takes a hit every time I read the title of this post. At least it contains the word “fix”.

People have reported a memory leak on a few occasions, but I’ve never been able to find it and neither have anyone else. I just left it because it has never bothered me. It might be because of a very forgiving hosting partner that just adds more RAM if necessary and never tell me.

Yesterday evening I found myself in the right mood for tracking down this leak and it only took me 6 hours to find it. The fix took about 8 seconds, but what jolly 8 seconds that was.

The problem

After six hours I found that the leak was in the Related Posts server control. The constructor registered an event handler for the Post.Saved event, but the constructor wasn’t static like all the other controls. It was public which means that at every page view the event handler would be registered. That resulted in that the control never got disposed because of the reference to the event. So for each page view, an equal number of controls got stuck in memory and couldn't be garbage collected.

The fix

Make the constructor and event handler static so they only run once in the application life cycle. Let this be a lesson to all, remember to unhook your event handlers. The fix works for BlogEngine.NET 1.3, 1.3.1 and 1.4 and you just have to replace one file in the App_Code folder.

Download the memory leak fix at CodePlex and follow the instructions in the readme.txt.

I’m sorry it took so long to find this fix. I hope it hasn’t caused you too much trouble.

BlogEngine.NEXT

In the light of this and other bugs, we have decided to do a service release in a couple of weeks. Beside the memory leak fix, it will include many other tweaks, fixes and a few new minor features. It will be 100% backwards compatible with the current 1.4 release. If you have found some issues with 1.4 that you want fixed in the next release, please add them to the issue tracker.