How to Properly Configure and Tune Spring Boot's HikariCP Connection Pool - Why the Default of 10 Isn't Enough
Tuning steps to eliminate 'Connection is not available' errors in Spring Boot's HikariCP. Covers the default maximumPoolSize of 10 and the official formula (cores × 2 + 1), revising connectionTimeout from 30s to 3s, the relationship between maxLifetime and wait_timeout, and leak detection with leakDetectionThreshold, all with implementation examples. Includes comparison data showing timeout error rates reduced from 40% to 3% through configuration changes.