Database Connection Pooler

Overview

Configure and optimize database connection pooling using external poolers (PgBouncer, ProxySQL, Odyssey) and application-level pool settings to prevent connection exhaustion, reduce connection overhead, and improve database throughput.

Prerequisites

• psql or mysql CLI for querying connection metrics
• Access to database configuration files (postgresql.conf, my.cnf) for max_connections settings
• PgBouncer, ProxySQL, or Odyssey installed if using external pooling
• Application connection pool settings accessible (database URL, pool size parameters)
• Server CPU core count and available memory for pool sizing calculations

Instructions

1. Audit current connection usage by querying active connections:
   • PostgreSQL: SELECT count(*) AS total, state, usename FROM pg_stat_activity GROUP BY state, usename ORDER BY total DESC
   • MySQL: SHOW STATUS LIKE 'Threads_connected' and SHOW PROCESSLIST
   • Compare against max_connections setting to determine headroom