Object cache on Spark executors

Question

A good question for Spark experts.

I am processing data in a map operation (RDD). Within the mapper function, I need to lookup objects of class A

Answer 1

In case serialisation turns out to be impossible, how about storing the lookup objects in a database? It's not the easiest solution, granted, but should work just fine. I could recommend checking e.g. spark-redis, but I am sure there are better solution out there.