Connection Exhaustion from Misconfigured Max Connections
criticalWhen active connections approach or exceed max_connections, new client connection attempts are rejected with 'Too many connections' errors. This blocks application access to the database and can cascade into application failures and user-visible downtime.
Monitor DatabaseConnections (CloudWatch) or Threads_connected (MySQL status variable) against max_connections setting. Alert when Threads_connected exceeds 80–90% of max_connections. Check Aborted_connects for rejected connection attempts. High Threads_running with stalled queries can indicate connection pool leaks or long-running transactions holding connections.
Increase max_connections in the DB parameter group if legitimate load exceeds current limit. Investigate application connection pooling—ensure pools release connections promptly and use appropriate pool sizes. Identify and terminate long-running or idle connections. Optimize queries to reduce execution time and free connections faster. Monitor for connection leaks in application code.