Description
After upgrade from Spring Boot 2.2.6 to 2.2.7 application started consuming much more memory.
In particular Heap Dump shows significantly higher number of instances of type:
org.springframework.boot.loader.jar.JarFile.
Heap Dump (v2.2.6) is here.
It contains the following number of instances:
Heap Dump (v2.2.7) is here.
It contains the following number of instances:
The number of instances is significantly higher.
Reason
After checking the history of related changes there is a couple of commits that worth to be checked:
Create new JarFile instance for URL connections
Attempt to prevent JarFiles from being left open
Attempt to prevent JarFiles from being left open
Steps to reproduce
The following repository can be used: https://github.com/alexey-anufriev/spring-boot-2.2.7-memory-leak#steps-to-reproduce
Comment From: philwebb
Thanks for the sample application, it's been very helpful. My initial thoughts are that commit c85918b8b35ee6215583020c2ef4287c4f7eca8d may have caused the problem, and it's likely to only occur on Java 11.
From the profiler, it looks like java.util.zip.ZipFile.CleanableResource.FinalizableResource might be the thing keeping the reference. It appears that any JarFile implementation that override close() will end up with finalizer based cleanup.
I'm really not sure how we can fix this one and also keep the fix for #17796. The only idea I've had so far is to create a new JarFile implementation that doesn't override close().
We'll need to do some experiments.
Comment From: philwebb
@alexey-anufriev I think I may have a fix for this, but I'm not 100% confident. If you get the chance, could you please try 2.2.10.BUILD-SNAPSHOT and let me know if you still see the issue?
Comment From: alexey-anufriev
@philwebb, I have already tried the same app with 2.2.10.BUILD-SNAPSHOT and it looks much better. There is a number of wrappers in the heap, but I do not think it will cause problems.
In any case, thank you for the resolution, and I will keep you updated after I get this version live (but it will take me some time).