Hydronitrogen Tech Blog

If you've dug around into the Spark SQL code, whether it's in catalyst, or the core code, you've probably seen tons of references to Logical and Physical plans. These are the core units of query planning, a common concept in database programming. In this post we're going to go over what these are at a high level and then how they're represented and used in Spark. The query planning code is especially important because it …

Note: This is being written as of early December of 2015 and currently assumes Spark 1.5.2 API. The data sources API has been out for a few versions now but it's still stabilizing so some of this might change to be out of date.

I'm writing this guide as part of my own exploration on how to write a data source using the Spark SQL Data Sources API. We'll start with exploration of …