Comment 11 for bug 143657

You should not expect to see differences in the ZODB cache. The functional end result with or without the optimazation
is identical: each persistent reference is transformed into a ghost object. However, with optimized references, the ghost
can be created with information from the reference only while with unoptimized references, a storage load is necessary.

You can verify the effect of the optimazation by calling "ZODB.serialize.ObjectWriter.persistent_id". It will return "oid, cls"
for optimized persistent references and "oid" for unoptimized ones.

Alternatively, you can debug log the ZEO interaction and check the number of ZEO load operations perfomred
(I used an equivalent instrumentation of "ZEO.ServerStub.StorageServer.zeoLoad" for the verification).