How to Monitor Your MySQL Database with Vigilmon

MySQL powers some of the world's busiest applications — WordPress, Shopify, and countless others. When MySQL goes down, your entire application stops. Setting up reliable monitoring is one of the highest-leverage investments you can make.

This guide shows you how to monitor MySQL using Vigilmon, a free uptime monitoring platform built for developers.

Common MySQL Failure Modes

MySQL doesn't just "go down" — it degrades:

• Max connections reached — new connections get Too many connections errors
• Deadlocks — transactions lock each other out and roll back
• InnoDB buffer pool pressure — disk I/O spikes as memory runs out
• Replication broken — your replica stops syncing, serving stale reads
• Slow query accumulation — one bad query brings the server to a crawl

Vigilmon catches the end result: when your app can't reach MySQL, your health endpoint returns an error and Vigilmon fires an alert within 60 seconds.

Building a MySQL Health Endpoint

PHP / Laravel

// routes/api.php
Route::get('/health/db', function () {
    try {
        DB::select('SELECT 1');
        return response()->json(['status' => 'ok', 'db' => 'mysql'], 200);
    } catch (\Exception $e) {
        return response()->json(['status' => 'error', 'db' => $e->getMessage()], 503);
    }
});

Python / Django

from django.http import JsonResponse
from django.db import connections
from django.db.utils import OperationalError

def health_mysql(request):
    try:
        conn = connections['default']
        conn.cursor().execute('SELECT 1')
        return JsonResponse({'status': 'ok', 'db': 'mysql'})
    except OperationalError as e:
        return JsonResponse({'status': 'error', 'db': str(e)}, status=503)

Node.js / Express

const mysql2 = require('mysql2/promise');

const pool = mysql2.createPool({
  host: process.env.DB_HOST,
  user: process.env.DB_USER,
  password: process.env.DB_PASS,
  database: process.env.DB_NAME,
  waitForConnections: true,
  connectionLimit: 10
});

app.get('/health/db', async (req, res) => {
  try {
    await pool.query('SELECT 1');
    res.json({ status: 'ok', db: 'mysql' });
  } catch (err) {
    res.status(503).json({ status: 'error', db: err.message });
  }
});

Setting Up Vigilmon Monitoring

1. Create a free account at vigilmon.online
2. Add an HTTP monitor pointing to /health/db
3. Set check interval: 1 minute
4. Configure alerts (email, Slack webhook, or PagerDuty)
5. Enable multi-region consensus — Vigilmon won't alert unless multiple regions confirm the failure

TCP Port Monitor (Backup)

MySQL listens on port 3306. Add a TCP monitor as a secondary check:

• Host: your MySQL server IP or hostname
• Port: 3306
• This catches cases where MySQL crashes completely

Advanced MySQL Health Checks

Check Connection Count

SHOW STATUS LIKE 'Threads_connected';
-- Alert if Threads_connected > 80% of max_connections
SHOW VARIABLES LIKE 'max_connections';

Check Replication Status

SHOW SLAVE STATUS\G
-- Look for:
-- Slave_IO_Running: Yes
-- Slave_SQL_Running: Yes
-- Seconds_Behind_Master: 0

Slow Query Detection

SHOW STATUS LIKE 'Slow_queries';

Response Time Monitoring

Vigilmon tracks not just uptime but response time. For MySQL health endpoints:

• <50ms: Healthy — simple SELECT 1 should return instantly
• 50-200ms: Degraded — MySQL is under load
• >500ms: Critical — likely lock contention or I/O pressure

Set a response time alert at 300ms to catch slowdowns before they become outages.

Alerting Strategy

Scenario	Alert Severity	Action
/health/db returns 503	Critical — page on-call	Restart MySQL or failover
Response time >300ms	Warning — Slack alert	Check slow query log
TCP 3306 not responding	Critical — page on-call	Check MySQL process
Replication lag >30s	Warning	Check replica error log

Production Checklist

• [ ] Health endpoint with SELECT 1 and timeout
• [ ] TCP monitor on port 3306
• [ ] Replication health endpoint (if using replicas)
• [ ] Response time threshold alert (300ms)
• [ ] Alert routing: critical → PagerDuty, warning → Slack
• [ ] Maintenance windows for schema migrations

Why Multi-Region Monitoring Matters

A single-location health check generates false positives from regional network blips. Vigilmon runs checks from multiple global regions and only alerts when a majority confirm the failure. This eliminates alert fatigue while keeping true MTTD under 2 minutes.

Start monitoring your MySQL database for free →

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Vigilmon is an uptime monitoring platform for developers. Free tier includes 10 monitors with 1-minute checks.