...

AEP Engine Statistics are most useful as a relatively light-weight means of benchmarking applications built on the X Platform during development. They include details about inbound and outbout outbound message throughput (raw counters and rates), transaction performance stats, per-event/message type latencies, store stats/latencies and more.

...

Developers building applications on top of X will often want to record their own application-specific statistics. In X parlance, these are "User Defined App Stats".

...

Where AEP Engine Statistics capture the statistics associated with a single AEP engine, Server Statistics pertain to the server itself (e.g. load average, memory usage, per-thread CPU utilization, object pools) and all applications/engines therein. Server stats are periodically collected and emitted packaged as Server Hearbeats Heartbeats that are modeled as ADM Messages. The server can:

...