What will spark do if I don't have enough memory?

Question

I'm new to Spark, and I found the Documentation says Spark will will load data into memory to make the iteration algorithms faster.

But what if I have a log file of 10GB and only have 2GB memory ? Will Spark load the log file into memory as always ?

Answer 1

I think this question has been well answered in the FAQ panel of Spark website (https://spark.apache.org/faq.html):

• What happens if my dataset does not fit in memory? Often each partition of data is small and does fit in memory, and these partitions are processed a few at a time. For very large partitions that do not fit in memory, Spark's built-in operators perform external operations on datasets.
• What happens when a cached dataset does not fit in memory? Spark can either spill it to disk or recompute the partitions that don't fit in RAM each time they are requested. By default, it uses recomputation, but you can set a dataset's storage level to MEMORY_AND_DISK to avoid this.