Chuck Blake gives an example of joining two streams of data together in Wallaroo:
The joining event streams pattern takes multiple data pipelines and joins them to produce a new signal message that can be acted upon by a later process.
This pattern can is used in a variety of use cases. Here are a few examples:
Merging data for an individual across a variety of social media accounts.
Merging click data from a variety of devices (e.g. mobile and desktop) for an individual user.
Tracking locations of delivery vehicles and assets that need to be delivered.
Monitoring electronic trading activity for clients on a variety of trading venues.
Conceptually, it’s very similar to normal join operations, but there is a time element which complicates things.