Prometheus Time Series

Prometheus Time Series is the study of how time-series databases work at a deep level: data structures, compression, indexing, query planning, and optimization. Unlike end-user Prometheus usage (configuring Prometheus to monitor systems), this skill focuses on the architecture and internals, how Prometheus stores millions of metrics, compresses them, and answers queries efficiently. Key concepts: label indexing, gorilla compression, cardinality explosion, memory-mapped storage, query planning, and time-series specific optimizations.