The previous version of SimplePush only supported an in-memory datastore and these operation where called directly from the Netty handler. These operations will are performed using the event loop which is not good as now that we've added other types of datastore, mainly database, these operation are quite long lived can cause performance issues.

This task should look into how we can make sure that these operations are not done in the event loop. As we are now using SockJS this might have to be looked into from that end. Perhaps there should be a way to configure an executor for the SockJSServices in Netty.