This data doesn’t arrive all at once, in reality. It arrives in a stream, and so it’s natural to run these kind of queries continuously. This is simple with Apache Spark’s Structured Streaming, and proceeds almost identically.

Of course, on the first day this streaming analysis is rolled out, it starts from nothing. Even after two quarters of data here, there’s still significant uncertainty about failure rates, because failures are rare.

An organization that’s transitioning this kind of offline data science to an online streaming context probably

doeshave plenty of historical data. This is just the kind of prior belief about failure rates that can be injected as a prior distribution on failure rates!

Bayesian approaches work really well with streaming data if you think of the streams as sampling events used to update your priors to a new posterior distribution.

Kevin Feasel

2019-02-20

Data Science, Hadoop, Python, Spark