[jboss-jira] [JBoss JIRA] Resolved: (JGRP-205) Out-of-band messages

Out-of-band messages -------------------- Key: JGRP-205 URL: http://jira.jboss.com/jira/browse/JGRP-205 Project: JGroups Issue Type: Feature Request Affects Versions: 2.2.8, 2.2.9, 2.3, 2.2.9.1 Reporter: Bela Ban Assigned To: Bela Ban Fix For: 2.5 We need to be able to tag individual messages with a quality-of-service bit: ASYNC. This means that, when such a message is received, it can be delivered asynchronously, e.g. by a thread from a separate threadpool (compared this to http://jira.jboss.com/jira/browse/JGRP-181). Examples for OOB messages: - ACKs (unicast) - XMIT requests (NAKACK) - Credit replenishment messages (FC) - Failure detection: heartbeats and are-you-alive messages, plus acks We might even introduce priority based message delivery One example for FC: - We have members A and B - A and B continuously invoke put()s on the TreeCache in *synchronous* mode - When B receives a put() request, it applies it and wants to send the response. However, assume that the response is blocked in FC.down() because we don't have enough credits available to send the response to A - Now A sent a REPLENISH message to B, but B is still stuck in the FC.down() method, which blocks the *up thread* ! - Therefore B cannot handle the replenishment message from A and therefore won't unblock: deadlock ! - If we could deliver the REPLENISH message from A to B *on a separate thread*, B would receive the REPLENISH message and unblock the FC.down() method