Issue4810

[jbescos]

This refers to the issue #4810

When there are many requests, some threads are blocked forever waiting for a CompletableFuture that is never completed. This is reproducible in the test. Usually this means one of these 2 possibilities:

1. There is an unexpected workflow that is not completing the requests.
2. There is one issue with concurrence.

In the original issue there are some errors related to:

Exception in thread "jdk-connector-9566" java.lang.IllegalStateException: Request not found
        at org.glassfish.jersey.jdk.connector.internal.DestinationConnectionPool.getRequest

Right after that method, the request should be completed, but this does not happen when there is that error.

With the test I saw that when the thread blocks forever, it is possible to see some leftovers in 'requestsInProgress':

idleConnections: []
connections: []
pendingRequests: []
requestsInProgress: {org.glassfish.jersey.jdk.connector.internal.HttpConnection@24063407=org.glassfish.jersey.jdk.connector.internal.DestinationConnectionPool$RequestRecord@71cf2f80, org.glassfish.jersey.jdk.connector.internal.HttpConnection@739f3f9b=org.glassfish.jersey.jdk.connector.internal.DestinationConnectionPool$RequestRecord@3ca2389c, org.glassfish.jersey.jdk.connector.internal.HttpConnection@5788db8d=org.glassfish.jersey.jdk.connector.internal.DestinationConnectionPool$RequestRecord@759c7d70, org.glassfish.jersey.jdk.connector.internal.HttpConnection@4ba397a6=org.glassfish.jersey.jdk.connector.internal.DestinationConnectionPool$RequestRecord@5b983bdf, org.glassfish.jersey.jdk.connector.internal.HttpConnection@50dc70da=org.glassfish.jersey.jdk.connector.internal.DestinationConnectionPool$RequestRecord@5b339b0, ...

These requestsInProgress are stored in a HashMap, and multiple threads can access it (for example in DestinationConnectionPool#getRequest and DestinationConnectionPool#processPendingRequests). I just changed it by a ConcurrentHashMap and I am not able to get the issue anymore.

[jbescos]

I set this as a draft because I am still investigating more.

[jbescos]

I am not able to reproduce any issue more but it is possible that there are more.

[senivam]

LGTM