TensorFlow on Spark is for learning, Vespa is for serving.
Where Vespa excels is in evaluating a learned model very quickly over lots of documents. We're working on providing support for running models learned with TensorFlow directly. For now people make the translation on their own.
I don't want to trigger any bot detection by voting all your comments up in a short amount of time. So, I will say thank you and mention that is is contributions from people like you that keep me coming back.
is it used inside Yahoo - because Vespa comes with its own tensor processing engine. I wondered who would use one over the other.