Turning run_combiner() performance for Hail local mode

[tpoterba]

Spark requires a special environment variable to configure JVM method. See this post:

How do I increase the memory or RAM available to the JVM when I start Hail through Python?

You can set the memory using an environment variable: PYSPARK_SUBMIT_ARGS="--driver-memory 8g --executor-memory 8g pyspark-shell" ipython This will start an ipython notebook with 8 GB of memory. If you want ipython to always start with 8 GB of memory, you can add this to your .bashrc (or the equivalent file for your shell): export PYSPARK_SUBMIT_ARGS="--driver-memory 8g --executor-memory 8g pyspark-shell"

I hope this helps! The executor summary certainly indicates there might be some GC thrashing happening.