Why Does Your Flink Job OOM? Uncovering JVM Non‑Heap, Direct Memory and NMT Secrets
This article explains the meaning of JVM Non‑Heap metrics, clarifies why Direct/Mapped memory is not part of Non‑Heap, analyzes a Flink taskmanager OOM case, and demonstrates how Native Memory Tracking (NMT) can reveal hidden memory gaps caused by allocator strategies such as TCMalloc and PTMalloc.