Finding Memory Leaks in the Ruby Ecosystem | Rails at Scale

Until recently, Ruby lacked a mechanism for detecting native-level memory leaks from within Ruby and native gems. This was because, when Ruby terminates, it does not free the objects that are still alive or the memory used by Ruby’s virtual machine. This is because the system will reclaim all the memory used anyway, so it’s just extra work that would make Ruby’s shutdown slower. However, this meant that it was impossible to determine whether a piece of memory was leaked or was just not cleaned up.