Underneath the Dashboard URL, there is this query invoked:

https://github.com/aerogear/aerogear-unifiedpush-server/blob/master/model/jpa/src/main/java/org/jboss/aerogear/unifiedpush/jpa/dao/impl/JPAInstallationDao.java#L198

It uses sub-selects, which are not good, and can be (very) slow.

The overall idea is to replace it with a proper join, like:

select
    count(installation)
from
    Installation installation, Variant t
where
    installation.variant = t.variantID
    and t.developer = :developer