Spark Memory Management Unveiled: “The Hidden Cheese in Your Data Fondue 🧀”

Vivek Murali
5 min readSep 22, 2023
Photo by Gavin Barnett on Unsplash

Hello there, data enthusiasts! 🙌 Ever felt like you’re trying to catch a greased pig when dealing with Apache Spark’s memory management? Well, you’re not alone! Let’s embark on this journey together, and who knows, by the end of it, we might just become the ‘Pied Pipers’ of Spark memory management! 😄

Spark Architecture

Spark Memory Management: The Building Blocks 🧐

Apache Spark, our beloved distributed computing system, is like a master chef in the world of data processing. It knows precisely how much of each ingredient to use to whip up the perfect dish. In Spark’s case, these ingredients are executor memory, driver memory, and overhead memory.

Apache Spark Unified Memory Manager

Executor Memory: The Mixing Bowl 🍲

Executor memory is the heap size of the executor. Think of it as the size of our chef’s mixing bowl. The bigger it is, the more tasks can run concurrently. However, just like in cooking, too large a bowl can lead to wastage, while too small can result in your application running out of memory.

Driver Memory: The Workspace 🧑‍🍳

Driver memory refers to the heap size of the driver program. It’s like the chef’s workspace — more space allows for better multitasking. But, just as in a real kitchen, too much space can lead to inefficiencies. Therefore, allocating the right amount of memory to your driver program is crucial.

Overhead Memory: The Chef’s Tools 🍴

Overhead memory is used by non-execution components like the JVM itself. It’s akin to the chef’s tools — knives, spoons, whisks. They don’t directly contribute to the dish, but they are essential for cooking. In Spark, overhead memory assists in tasks like network communication and maintaining internal data structures.

spark-yarn-memory-usage.

Resource Allocation: The Secret Recipe 📜

Different organizations have diverse needs for cluster memory management, just as some prefer spicy over sweet in their meals. There’s no one-size-fits-all recommendation for resource allocation. Instead, it can be calculated based on the available cluster resources.

Let’s dive into a hypothetical calculation:

Scenario: Processing 1TB of Data 🔍

Imagine you have a Spark cluster with the following specifications:

  • Total nodes in the cluster: 10
  • Cores per node: 16
  • Memory per node: 120GB
  1. Number of Executors: Calculate num-executors as total-cores-in-cluster = num-cores-per-node * total-nodes-in-cluster = 16 * 10 = 160.
  2. Executor Cores: Set executor-cores to 1, meaning one executor per core.
  3. Executor Memory: Calculate executor-memory as mem-per-node/num-executors-per-node = 120GB/16 = 7.5GB.

With these settings, your Spark application will have 160 executors, each with 1 core and 7.5GB of memory.

Please note that these calculations are hypothetical and should be adjusted based on your specific use case and environment. Monitoring your application’s memory usage using Spark’s web UI is crucial.

Executor, Core, and Memory Distribution: The Perfect Mix 🥗

Finding the optimum distribution of Memory, Executors, and Cores for a Spark Application within available resources is crucial. It’s akin to finding the perfect mix of ingredients for your dish.

Imagine you have the same cluster as before (10 nodes, 16 cores, 64GB memory per node). You could distribute your resources in several ways:

  • Scenario 1: Allocate 4 cores and 16GB of memory to each executor, resulting in 40 executors.
  • Scenario 2: Allocate 2 cores and 32GB of memory to each executor, resulting in 80 executors.
  • Scenario 3: Allocate 8 cores and 8GB of memory to each executor, resulting in 20 executors.

Each scenario has its pros and cons, and the best choice depends on your specific use case.

Memory Management in Spark: The Secret Sauce 🥫

Understanding how Spark manages its resources is like uncovering the secret sauce of a recipe. It’s what gives Spark its unique flavor and sets it apart from other distributed computing systems.

In Spark, memory management is divided into two regions: execution and storage. Execution memory is used for computation in shuffles, joins, sorts, and aggregations, while storage memory is used for caching and propagating internal data across the cluster.

What’s intriguing is that Spark has a unified memory manager that seamlessly shares memory between execution and storage. This allows cached data to be evicted to make room for computation and vice versa. It’s like a chef effortlessly switching between chopping vegetables and stirring the pot to ensure nothing gets burnt!

Spark Configurations: The Cooking Instructions 📝

Just like a recipe has cooking instructions, Spark has configurations. These settings control how Spark behaves and uses resources. Some critical configurations include spark.executor.cores, spark.executor.instances, spark.executor.memory, spark.driver.memory, spark.driver.cores, and more.

For example, spark.executor.memory controls the memory per executor, while spark.executor.cores determines the number of cores per executor.

Conclusion: The Perfect Dish! 🎉

And voila! We’ve cooked up a storm understanding Apache Spark’s memory management! Remember, these are just guidelines. Always taste and adjust based on your specific use case and environment. Start with a small amount of memory and gradually increase it until you find the optimal amount.

So, the next time you’re dealing with Apache Spark’s memory management, remember — you’re not just a data enthusiast; you’re a master chef in the making! Now go forth and cook up some data magic! 🎩✨

And remember folks — too many cooks may spoil the broth, but too many cores… well, that just spoils your cluster! 😂 Until next time!

In this comprehensive guide, we’ve explored the fundamentals of Apache Spark’s memory management, delved into resource allocation scenarios, uncovered the secret sauce of Spark’s memory management, and provided you with the cooking instructions through Spark configurations. Armed with this knowledge, you’re now ready to conquer Spark’s memory challenges like a seasoned chef!

This blog post was cooked up using information from various sources, including Hitachi Vantara, LinkedIn Article, Medium Article, Perficient Blogs, Spark Notes, and Saturn Cloud Blog.

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Vivek Murali

Data Engineer @iVoyant | Machine Learning, Data Engineering & Data Enthusiast| Travel and Data insights only things amuses me.