MERGE3 not working with TCP using ForkJoinPool ---------------------------------------------- Key: JGRP-2406 URL: https://issues.redhat.com/browse/JGRP-2406 Project: JGroups Issue Type: Bug Affects Versions: 4.1.8 Reporter: Olivier Peyrusse Assignee: Bela Ban Priority: Minor Fix For: 4.2.0 Attachments: logs.tgz, project.zip, timeline.txt With JDK11, using the TCP protocol with the ForkJoinPool is causing constant failures of MERGE3. I consistently observed the following, from the point of view of a member M - M asks for other coordinator views. It contacts A and B - A and B send their views - M waits and timeouts for receiving views and abort the merge - immediately after aborting the merge, M process messages containing the views of A and B. In [^timeline.txt], you will see the extracts for logs from the various members at play. After many experiments, the one parameter causing this issue is in the TCP protocol. {code:xml} <TCP ... thread_pool.use_fork_join_pool="true" /> {code} Setting {{thread_pool.use_fork_join_pool}} to true repeatedly produces the problem, while using {{thread_pool.use_fork_join_pool}} with false works fine. Project details: - as tested within Kubernetes, this project uses KUBE_PING as its discovery protocol - to understand the reason for the failed merges, I created the protocol MERGE4, that is MERGE3 with additional logs. - [^logs.tgz] contains all logs from the various members involved in the test.