[jboss-jira] [JBoss JIRA] Commented: (JGRP-1309) Discovery: max_rank doesn't make any sense

Discovery: max_rank doesn't make any sense ------------------------------------------ Key: JGRP-1309 URL: https://issues.jboss.org/browse/JGRP-1309 Project: JGroups Issue Type: Task Reporter: Bela Ban Assignee: Bela Ban Fix For: 3.0 Discovery.max_rank was originally meant to reduce traffic in the discovery phase: rather than 100 members replying to a discovery request, only the coordinators (max_rank=1) would reply and this would be enough for a joiner to find the coordinator and send it a JOIN request. However, discovery responses also contain additional information, such as the logical name (if set) and the physical address of a member. This is needed by all members of a cluster, and so everyone should return this information to a new joiner. Seen under this aspect, max_rank is useless and even conter-productive ! If we have 100 members: - max_rank=0: we get 100 discovery responses - max_rank=1 (sets return_entire_cache to true): the coordinator return the entire cache to the joiner (1 unicast / cache entry: 100 unicasts) - max_rank=2: the coordinator plus the next in line return the entire cache: 200 unicasts - and so on The current problem is that ergonomics sets return_entire_cache which - in conjunction with max_rank > 0 - generates even more discovery responses than is max_rank is 0 !