Akka actor memory leak using Akka Http - scala

Question

I am using Akka-http with scala. I've a class MainApp which is initialized at the startup and has a ActorRef.
abstract class MainApp{
def actorSystem: ActorSystem
def myService: ActorRef
def stop(): Unit = {
actorSystem.terminate()
}
}
object MyMain {
def main(args: Array[String]): Unit = {
implicit val system = ActorSystem("my-actor-system")
implicit val executionContext: ExecutionContextExecutor = system.dispatcher
val app = new MainApp {
override def actorSystem: ActorSystem = system
val dbPool: MyDbManagement = new MyDbManagement(someConfig)
override def preProcessorService: ActorRef =
actorSystem.actorOf(
Props(new MyService(actorSystem, dbPool))
.withDispatcher("processing-dispatcher")
)
}
val httpBindingFuture = Http().newServerAt("0.0.0.0",httpPort).bind(app.http.route)
....//start server and add shutDown hooks
The actor class receives a message and looks like the following
class MyService(actorSystem, dbPool){
override def receive: Receive = {
case SendMessage(request) => {
val actorSender = sender()
implicit val executionContext = actorSystem.dispatchers.lookup("db-blocking-dispatcher")
try {
val encryptedReq = dbPool.encrypt(request)
val responseFuture = dbPool.sendToDb(request)
responseFuture.onComplete { //handle error codes and return something like
actorSender ! MyResponse(202, "Accepted")
}
}
}
I've one http route, which asks the message
path("send") {
post {
entity(as[MyPojo]) { request =>
onSuccess(app.MyService ? SendMessage(request)) {
case response: MyResponse => {
complete(response.statusCode, response)
}
}
}
}
}
Problem-Statement: I've created only 1 actor in the application but there are multiple dispatchers(fork-join-executor) which performs multiple tasks and to free the default-dispatcher so that it can accept non-blocking incoming requests. Number of incoming requests are very high.
This application has a memory leak and degrades over time(heap size increases and full GC occurs which takes time and CPU)
I've taken a heap dump when it was in the degraded state.
During the investigation on MAT tool,
the major leak suspect was LocalActorRef
One instance of "akka.actor.LocalActorRef" loaded by "jdk.internal.loader.ClassLoaders$AppClassLoader # 0x609c0ee58" occupies ~7GB (95.80%) bytes.
Class Name | Shallow Heap | Retained Heap
akka.actor.LocalActorRef| 24 | ~ 7 GB
I would like to know what is causing this memory leak?
If there are any more design related questions or suggestions, let me know.
I've gone through the following but none helped:
https://discuss.lightbend.com/t/localactorref-memory-leak-and-full-gc-allocation-failure-causing-gc-to-take-too-long/7216/6
Akka Actor Memory Leak or Management
I've also thought of using Futures but with Futures the application has higher latencies