MERGE3: a dead member as merge leader will never trigger a merge ---------------------------------------------------------------- Key: JGRP-2276 URL: https://issues.jboss.org/browse/JGRP-2276 Project: JGroups Issue Type: Bug Reporter: Bela Ban Assignee: Bela Ban Fix For: 4.0.12 When we have member(s) which have a view with a dead member as coordinator, when the dead member becomes part of the subgroup coordinators and _happens to be chosen as merge leader_, then a merge will never ensue. Example: * Member 2 (with view 2|5) was the previous coordinator and left the cluster, installing view 3|6 before stopping ** View 2|5=\{2,3,4,5,6,7\}; view 3|6=\{3,4,5,6,7\} * Member 7 didn't get view 3|6 and still has view 2|5 * Everybody else has view 3|6 * MERGE3 gets the following views: ** 2|5: 7 // member 7 has this view ** 3|6: 3,4,5,6 // members 3,4,5 and 6 have this view * 2 and 3 are added to a _sorted set_ and the first member of the set (2) is chose as merge leader. 3 doesn't take any action, as it notices it won't be the merge leader ** The reason 2 was first in the sorted set is that (possibly by coincidence) its UUID is *lower* than that of 3. If this wasn't the case, 3 would be merge leader and start (and successfully complete) a merge. However, with dead member 2 being picked as merge leader, a merge will never be triggered!