Based on http://lists.jboss.org/pipermail/aerogear-dev/2014-December/010125.html

• POSTGRES
  With Postgres I got reasonalbe/good results:
  16 threads/1000 loops -> unit test took 50 seconds. (16k devices)
  32 threads/1000 loops -> unit test took 120 seconds. (32k devices)

Would be nice if we could improve this (e.g. with better JPQL or something like that)