Spark Executor - Parallelism Question

SANJAYKJ — Wed, 19 Mar 2025 06:06:54 GMT

I was reading the book Spark: The Definitive Guide, I came across below statement in Chapter 2 on partitions.

"If you have many partitions but only one executor, Spark will still have a parallelism of only one because there is only one computation resource."

I am little puzzled, is the above statement makes assumption that executor is having only one core ?

Re: Spark Executor - Parallelism Question

Isi — Wed, 19 Mar 2025 09:21:09 GMT

Hey @SANJAYKJ

It is correct in the sense that a single executor is a limiting factor, but the actual parallelism within that executor depends on the number of cores assigned to it. If you want to leverage multiple partitions effectively, you either need more executors or executors with more cores.

If the single executor has multiple cores, then it can process multiple partitions at the same time, up to the number of available cores.

🙂

Isi

topic Spark Executor - Parallelism Question in Administration & Architecture

Spark Executor - Parallelism Question

Re: Spark Executor - Parallelism Question