How to profile memory usage in an ArangoDB Foxx App

Question

Stress testing my Foxx App eventually crashes ArangoDB with a SIGSEGV. Looking at the core file it seems to be related to V8 running out of memory. I'd like to do memory profiling on the heap to help track down potential leaks. Since the V8 engine is an integral part of arangod, how do I access and use the V8 profiler? The node modules that help with this all have C++ modules so they won't run right under Foxx.

Answer 1

Unfortunately, the V8 engine and its garbage collection has some glitches regarding the memory management.

In some cases, it runs in tight loops to squeeze a bit more memory out of the system, sometimes it instantly terminates the process instead of giving its host process a chance to cope with the situation.

This is a problem with which all V8 based solution have to fight - Node.JS too. The V8 team is working on this, and with every version they make progress. But the end of the road isn't reached yet by now.

Regarding debugging interface which would most probably also provide the memory profiling, we are well aware of that its currently missing and tracking progress on this via the github issue #1538 . As resources become available for this topic, we will start working on it.

You probably can use flamgegraphs in some way right now with the aid of the linux kernel, but it seems to be problematic to write the names of the JIT compiled functions required to make this more usefull.