MySQL Error 1040: Too Many Connections

Symptom

ERROR 1040 (HY000): Too many connections.

Root cause

Connection count hit max_connections; usually a leak or a traffic spike.

Fix, in order

1. Inspect current connection sourcesSELECT SUBSTRING_INDEX(host,':',1) AS ip, COUNT(*) FROM information_schema.processlist GROUP BY ip ORDER BY 2 DESC;

2. Check wait_timeout is not absurdly highSHOW VARIABLES LIKE 'wait_timeout';

3. Raise the cap only with RAM headroom in mindSET GLOBAL max_connections = 300;

Prevent it coming back

Use a pooler and alert at 70% of max_connections.

Run it on clean infra

Spinning up a fresh box to reproduce or escape this error?

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Last reviewed 2026-10-02 · NinjaOps SEO grid · DevOps blog