[macjohnmcc]

Debugging issues with multithreaded code can be difficult because you could be looking at race condition that only happens when the code is running at full speed and debugging pausing one or all threads could give you an different experience than the real world.

[kaba0]

(Debug) logging can also change the frequency/order/synchronization of threads masking over race conditions.

[turtledragonfly]

Yeah, I have fought with this occasionally. It's one of the handful of "gotchas" you need to think of when designing logging, and interpreting its results.

Sometimes you can improve the situation by sticking things in a bigger memory buffer and tightening control of when things get flushed to disk, but there's always that fundamental "observing the system will change it" problem. Similar issues arise with a debugger too, of course.

[macjohnmcc]

Yeah I had to debug some code with 5 threads that were supposed to be synchronized through the use of several semaphores that was a bear to pin down.