How to Size Java Database Connection Pools in Kubernetes

This article explains how to properly size Java JDBC database connection pools in Kubernetes environments. It covers the importance of connection pool configuration, the impact of multiple pods on database connections, and practical guidance for setting maximumPoolSize, minimumIdle, and idleTimeout. Using Spring Boot with HikariCP as the primary example, the author discusses how connection pools work as caches and limiters, and emphasizes using the smallest pool size that meets performance SLAs. The article includes real-world scenarios like rolling deployments and canary versions, and references HikariCP's official pool-sizing formula.