Once hitting the max-connections limit, new connections are not accepted any more and CLOSE_WAIT connections increase gradually ------------------------------------------------------------------------------------------------------------------------------- Key: WFLY-9397 URL: https://issues.jboss.org/browse/WFLY-9397 Project: WildFly Issue Type: Bug Components: Web (Undertow) Affects Versions: 11.0.0.CR1 Reporter: Masafumi Miura Assignee: David Lloyd Once hitting the {{max-connections}} limit of listener, JBoss EAP does not accept new connections any more. Even after all request processing are completed, JBoss does not accept. So, any client can not connect to JBoss EAP. In addition, when a client send a new request and close the connection from client-side due to timeout or cancellation in such situation, CLOSE_WAIT connections remain until JBoss Java process is stopped. I think this issue is related to XNIO-276 and XNIO-279, which both fixes are merged in XNIO 3.4 branch but it's not merged (or partially merged) in XNIO 3.5 branch: - XNIO-276 - If QueuedNioTcpServer hits the max connection limit it gets stuck in an infinite loop This issue is fixed by the two commits [6a5d04e|https://github.com/xnio/xnio/commit/6a5d04e3be98ee68a9fb1f9f98eb4...] and [8c0af87|https://github.com/xnio/xnio/commit/8c0af87f5dfdee96af2e3000e47e6...] which were merged in 3.4 branch. However, 8c0af87 is not included in 3.5 branch. - XNIO-279 - QueuedNioTcpServer can go into an infinite loop if accept fails This issue is fixed by the commit [86d0f6c|https://github.com/xnio/xnio/commit/86d0f6cc4bc41443b7e9442989e56...] in 3.4 branch. However, this is not included in 3.5 branch. Note: JBEAP-6397 and JBEAP-8080 were raised to track the issues for 7.1.0. I think both are marked as resolved because 7.1.0 DR came with XNIO 3.4.x at that time. However, the latest 7.1.0 CR now comes with XNIO 3.5.x, so it regresses in the latest release.