To specify logical membership for the coordinator in a user-defined logical server, use the FOR LOGICAL COORDINATOR clause instead of the name of the current coordinator.
The logical membership of the coordinator means the coordinator is always available to the logical server as its member, regardless of which multiplex node plays the coordinator role.
The current coordinator node is available only to those logical servers that have the coordinator as its logical member, and not to those logical servers that have membership to the current coordinator node using the multiplex node name. If the current coordinator is both a logical member and a named member of a logical server, then it is available to the logical server, but only by virtue of its logical membership. The named membership is still considered ineffective.
The coordinator node membership rules ensure predictability of the workload on the coordinator. The coordinator is available to a known set of logical servers and that does not change as the coordinator fails over from one multiplex node to another.