Hi Peter,
I have fixed the issue with the unPublish.
I have did another commit in the code : changed the sql query at delete in active_watchers to use the callid,to_tag,from_tag unique key.
I also realised that for DB_ONLY mode an index on presentity_uri column is need, so I updated the database schema.
Let us know the results of the performance tests.
Regards, Anca