How to Diagnose and Fix MySQL Too Many Connections Errors in Production

When MySQL reports 'Too many connections', this guide walks you through emergency assessment, step‑by‑step diagnostics, quick mitigation scripts, root‑cause analysis of slow queries, connection leaks, short‑connection spikes, and long‑term solutions including parameter tuning, connection‑pool configuration, and Prometheus‑based monitoring to prevent future outages.

AlertmanagerConnection PoolConnection leak

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How to Diagnose and Fix MySQL Too Many Connections Errors in Production

MaGe Linux Operations

Oct 24, 2025 · Operations

Why Did TCP Connections Skyrocket from 15K to 65K? Full Diagnosis and Fix

This postmortem details a production outage caused by a sudden surge of TCP connections from 15 K to 65 K, explains how to reproduce the issue, walks through step‑by‑step diagnostics, root‑cause analysis, and permanent remediation using Linux kernel tuning, connection‑pool configuration, and monitoring alerts.

Connection leakLinuxTCP

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Why Did TCP Connections Skyrocket from 15K to 65K? Full Diagnosis and Fix

Qunar Tech Salon

Mar 8, 2018 · Backend Development

Analyzing Intermittent Timeouts and RST Packets in Apache HttpClient Calls

This article investigates an intermittent timeout issue caused by a Java Apache HttpClient implementation that leaks connections, explains why numerous RST packets appear during TLS shutdown, and presents experiments and code revisions that clarify the TCP/TLS interaction and proper resource handling.

Apache HttpClientConnection leakHTTP

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Analyzing Intermittent Timeouts and RST Packets in Apache HttpClient Calls