After applying the RU6 release for Management Platform 8.1, during replication cycles the parent began slowing down significantly to the point that all four child servers had differential cycles that had not completed in over 24 hours. Before RU6 the differential replication cycles took less than one hour.
The SMP logs on the parent contained deadlock warnings on user accounts.
During replication the Primary User data class (Inv AeX AC Primary User) is sent, but recent changes assume that the actual user account should be replicated with the computers being replicated. This can cause a lot of merging and synch events to be generated on the Parent's.
Generally the user accounts do not need to be replicated. If so they should be replicated in a rule by themselves.
The next time the child SMP replicates computers it will ignore sending/replicating the user accounts. It will only send the Primary User information related to each computer.