A qdstat -m shows
The router-internal memory pool numbers support the 5.57 MiB memory consumption.
From the process side, however, memory usage is much greater:
The huge 4.0g RES usage is (probably) an outgoing session buffer in proton that supports an interrouter link for which Q2 flow control is not in effect.
PROTON-2144 delivers instrumented proton memory usage. Stats available from that effort should be available in qpid-dispatch debug builds.