>How does one JOIN across not just tables but opaque services One solution we use is to have an event queue from service A to which service B is subscribed. In

>How does one JOIN across not just tables but opaque services One solution we use is to have an event queue from service A to which service B is subscribed. In the event handler, service B fills its own view table with data from service A. And then it can do joins on data from multiple services because everything is in the same DB. We require services to always emit "created" and "updated" events for its objects.