Concurrent mediations
Several messages might be mediated concurrently, to achieve maximum throughput for a selected mediated destination.
The maximum number of messages that can be mediated
concurrently at a selected destination is capped for each messaging
engine by the maximum size of the mediation thread pool.
The number of mediations that can be run concurrently
against any single destination is limited by the server workload profile.
You can specify that a mediation operates concurrently by setting the Allow Concurrent mediation property to True, by using the administrative console. If message ordering is important, do not allow concurrent mediations. By default (Allow Concurrent mediation is set to False), a single message is mediated at a time.