seniorApache Spark
Advanced Memory Tuning: Unified Memory vs Off-Heap.
Updated May 5, 2026
Short answer
Senior tuning involves balancing the JVM heap with Off-Heap (Tungsten) memory to minimize GC pressure.
Deep explanation
Large heaps (e.g., 64GB+) cause long Stop-The-World GC pauses. By moving data to Off-Heap (spark.memory.offHeap.enabled), we bypass the JVM GC for raw data storage and shuffle buffers.
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