Group-based eviction

Currently, Infinispan only supports size-based eviction. We can configure a cache with a specific max-entries, so if the size exceeds this value infinispan will evict any surplus entries.

However, if the cache has grouping enabled, it is perhaps more useful to use group-based eviction. In this scenario, max-entries would be interpreted as "max-groups", and infinispan would evict entire groups of cache entries if the number of groups exceeds this value.

In WildFly, web sessions make use of grouping. A single web session will map to a single group of multiple cache entries, where the number of entries is not necessarily the same for a given session. In this case, evicting per cache entry does not make sense - all entries of a session should be evicted or not at all. Also, users can specify the max number of sessions they want to remain in memory. Until infinispan supports group-based eviction, translating this value to an appropriate max-entries is cumbersome and imprecise.