[infinispan-issues] [JBoss JIRA] (ISPN-8962) PreferAvailabilityStrategy: Rely less on the stable topology

PreferAvailabilityStrategy: Rely less on the stable topology ------------------------------------------------------------ Key: ISPN-8962 URL: https://issues.jboss.org/browse/ISPN-8962 Project: Infinispan Issue Type: Bug Components: Core Affects Versions: 9.2.0.Final Reporter: Dan Berindei Assignee: Dan Berindei Fix For: 9.2.2.Final, 9.3.0.Alpha1 {{PreferAvailabilityStrategy}} checks the size of the stable topology, and only considers cache topologies that are derived from the biggest topology (in size) when picking a post-merge topology. Unfortunately, in some situations this algorithm fails pretty badly. If a node has a very long GC pause, when it comes back it will report the old topology *and* the old stable topology. If the rest of the cluster rebalanced, it now has both a smaller current topology and a smaller stable topology. Furthermore, the stable topology is updated asynchronously, independent from the current topology. So even if there's a split and the minority partition installs a current topology with fewer members, it may take some time for its stable topology to be updated with fewer members. In fact, it appears that when a rebalance is not needed (e.g. because the partition has a single node), the stable topology is never updated!