Spark 3.4.1 - implementing Join Operation on Large DataFrames Resulting in Memory Overflow
I'm collaborating on a project where I'm confused about This might be a silly question, but I'm working with a memory overflow scenario when performing a join operation on two large DataFrames in Spark 3.4.1. The DataFrames I'm working with have around 10 million rows each, and the join condition is based on a common key. I've tried using broadcast joins to optimize performance, but it seems like the memory usage spikes significantly, leading to the following behavior: ``` 21/10/12 12:00:00 behavior Executor: Exception in task 0.0 in stage 1.0 (TID 1) java.lang.OutOfMemoryError: Java heap space ``` Here's a simplified version of my code: ```python from pyspark.sql import SparkSession from pyspark.sql.functions import broadcast spark = SparkSession.builder.appName('JoinExample').getOrCreate() # Load the DataFrames large_df1 = spark.read.parquet('/path/to/large_df1.parquet') large_df2 = spark.read.parquet('/path/to/large_df2.parquet') # Attempting a broadcast join joined_df = large_df1.join(broadcast(large_df2), 'join_key') ``` I've also increased the executor memory settings in my Spark configuration: ```bash --executor-memory 4g --driver-memory 2g ``` Despite these efforts, I still run into memory issues. I've considered partitioning the DataFrames before the join, but I'm not sure if that's the best approach in this scenario. Are there any recommendations or best practices to handle such large join operations without hitting memory limits? Any insights on how to optimize this further would be greatly appreciated! I'm working on a API that needs to handle this. The stack includes Python and several other technologies. I'd really appreciate any guidance on this. This is part of a larger mobile app I'm building. Cheers for any assistance! This is happening in both development and production on Ubuntu 20.04. I'm working with Python in a Docker container on Ubuntu 22.04. Any advice would be much appreciated. I'm working on a microservice that needs to handle this. Any suggestions would be helpful.