Recently, we decided to investigate why our application ARANGOSYNC for synchronizing two ArangoDB clusters across data centers used up a lot of memory – around 2GB in certain cases. The environment contained ~1500 shards with 5000 GOroutines. Thanks to tools like pprof (to profile CPU and memory usage) it was very easy to identify the issue. The GO profiler showed us that memory was allocated in the function time.After() and it accumulated up to nearly 1GB. The memory was not released so it was clear that we had a memory leak. We will explain how memory leaks can occur using the time.After() function through three examples.