Connection Pool Management

Connection Pool Management

Managing database connections efficiently to maximize throughput and prevent resource exhaustion.

Context

You are configuring connection pools. Size appropriately; monitor usage.

Domain Context

• Pool Size: How many concurrent connections? Too few = waits; too many = resource exhaustion
• Connection Lifetime: How long should connection live? Connections age, become stale
• Health Checks: Validate connections before reuse
• Idle Timeout: Close unused connections; free resources
• Queuing: What happens when all connections are busy?

Instructions

1. Min/Max Size: Min = base connections; Max = peak + buffer
2. Max = (Number of Cores * 2) + Extra for I/O: Rule of thumb
3. Connection Lifetime: 30 minutes common; depends on database
4. Idle Timeout: 5 minutes; reclaim unused connections
5. Health Checks: Ping connection before using; catch stale connections
6. Queue Size: What happens if all connections busy? Queue or error?
7. Monitoring: Track pool utilization, wait times

Anti-Patterns

• Pool too small; queries wait forever
• Pool too large; resource exhaustion, slow start
• No health checks; stale connections cause errors
• No idle timeout; connections accumulate, eventually exhaust
• Not monitoring; don't know if pool is too small

Further Reading

• HikariCP documentation (Java)
• Connection pool best practices (AWS)
• Database connection tuning guides