Lambda isn't leaking memory, your metrics are lying to you

AWS Lambda's @maxMemoryUsed metric is a misleading high-water mark tracked across entire execution environments rather than per-invocation, causing false memory leak alerts that can trigger unnecessary and counterproductive optimization efforts. The article demonstrates how apparent memory growth is often caused by glibc arena hoarding rather than actual leaks, with practical solutions like adjusting malloc thresholds and optimizing allocator strategies. IT leaders need to recalibrate their monitoring and alerting strategies for Lambda workloads to avoid costly misdiagnosis of performance issues.