Database Connection Pool Sizing & Queuing Latency Calculator
Calculate optimal database connection pool size using PostgreSQL & HikariCP research (Core × 2 + Spindle), Little’s Law query concurrency, and queue wait latency to prevent CPU thrashing.
Database Server & Workload Parameters
cores
Physical or vCPU cores dedicated to DB engine.
Effective I/O spindle channel factor.
QPS
ms
Average active query duration at database engine.
nodes
MB
Memory allocated for sorting & joins per backend.
Pool Sizing Recommendation
OPTIMAL POOL HEALTH
Optimal DB Max Connections
17
Formula: 8 × 2 + 1 = 17
Per-App Instance Pool Size
4
Across 4 client instances
Little's Law Active Concurrency
7.5 connections
In-flight active queries (L = λ × W)
Dedicated Connection RAM
272 MB
17 conns × 16 MB work_mem
Performance & Queuing Analysis
Pool Utilization Rate:
44.1% (Healthy)
Average Queue Wait Time:
< 0.2 ms
PgBouncer / Proxy Requirement:
Direct Pool Suitable
HikariCP Configuration Snippet
dataSource.maximumPoolSize = 4
dataSource.minimumIdle = 4
dataSource.connectionTimeout = 10000
dataSource.idleTimeout = 600000
dataSource.maxLifetime = 1800000
dataSource.minimumIdle = 4
dataSource.connectionTimeout = 10000
dataSource.idleTimeout = 600000
dataSource.maxLifetime = 1800000