Why Database Connection Pools Crash Under Load

Lucas and Luna dig into a 2025 postmortem from a mid-size fintech that saw its payment API latency spike from 12 milliseconds to over 4 seconds during a routine marketing push. The culprit wasn't the database or the queries — it was the connection pool configuration. They walk through how HikariCP default settings interact with MySQL thread pooling, why max-lifetime and idle-timeout values can create a thundering-herd effect, and what the team changed to recover throughput. Along the way they touch on TCP keepalive tuning, the difference between a connection pool and a database connection, and why even experienced engineers treat pool size as a black box. If you've ever stared at a'HikariPool-1 - Thread starvation or clock leap detected' warning in your logs, this episode explains what it actually means. #DatabaseConnectionPool #HikariCP #MySQL #Fintech #API #Performance #ThunderingHerd #ConnectionPooling #Backend #DevOps #Scalability #Technology #FexingoBusiness #BusinessPodcast #Database #SQL #NoSQL #DataStorage Keep every episode free: buymeacoffee.com/fexingo