high memory usage for spring boot Path variable api

[rahulsingh336]

We have created one microservice with single endpoint. This api consist of single path variable and it is just returning OK response.
In real time, it will have different processing mechanism but for testing and POC purpose we have kept it simple.
Now, When we generate load with jmeter for this particular api and pass in random path variable values using random variable in jmeter then we have observed that memory is constantly increasing over a period of time and objects are not getting GC.

spring boot version:- 2.3.1 RELEASE
dependencies:- spring-boot-starter-web, spring-boot-starter-security, spring-boot-starter-actuator

Sample api:- /app/ping/{id} GET

Jmeter :- path = /app/ping/${random_var} - random_var having value in between 1 - 100000
Number of Threads:- 60
Ramp Up Seconds:- 1
Loop Count:- Forever
Spring boot app configuration:- -Xmx150m
Heap Dump:- Attached
VisvualVM screenshot:- Attached

Leak Suspect: Attached

heapdump-1600192132939_Leak_Suspects.zip

heapdump-1600192132939.zip

Please let me know If I am missing something.

[bclozel]

Could you share your sample application?

I'm seeing a lot of ConcurrentHashMap$Node instances held by Tomcat CachedResource entries.

Requests to Spring endpoints should not create such cache entries - those are usually only linked to static resources served by Tomcat.

[rahulsingh336]

attach below for reference:-
1.) sample application
2.) current heap dump
3.) memory leak - suspect zip
4.) visvual vm screen shot

demomemory.zip
heapdump-1600197736545.zip
heapdump-1600197736545_Leak_Suspects.zip

[bclozel]

Are you sure this is the right application?

The application you've sent doesn't build because the POM is broken (it's importing spring-boot-starter-parent instead of spring-boot-parent) and it's also using 1.5.18.RELEASE, which is not maintained anymore.

I've fixed the POM and changed the version to 2.3.1 RELEASE (the version noted in your original report) and I can't reproduce the behavior here. I'm running a lot of requests on that endpoint, as explained in your report and yourkit doesn't show the cached entries in the object explorer as leak suspects.

Could you check again your sample app and make sure that you're running Yourkit against the actual sample and not some other deployed application?

[rahulsingh336]

Sorry in original question version marked seems incorrect . Issue is on version "1.5.18.RELEASE".
Please try with version "1.5.18.RELEASE".
And what do you mean by POM is broken? The sample app was generated from "https://start.spring.io/" and version was changed.
AFAIK spring-boot-starter-parent provides default configurations for our application and a complete dependency tree to quickly build our Spring Boot project.
Please help me in understanding if I am missing some thing.

[rahulsingh336]

attached your kit memory snapshot
DemoApplication-2020-09-16.zip

[bclozel]

Sorry about the spring-boot-starter-parent note, you're right.

Unfortunately 1.5.18.RELEASE is not maintained anymore, so I'm closing this issue - if you can reproduce this on a supported version we'd be happy to take a look. For what it's worth, those objects should not leak as they have a TTL associated with them and they should be collected by the GC.

Thanks!