High-Cardinality Threat Detection: Why MapReduce Breaks and Heuristics Win

The Fundamental Problem: Signal Is Infinitesimal Compared to Noise Modern cloud systems operate at a scale where traditional data processing assumptions begin to break down. In large distributed environments, telemetry pipelines routinely process tens of billions of events per minute across millions of users, accounts, and resources. At this scale, the objective of threat detection is often misunderstood.