How to Resolve the “MySQL – Too Many Connections” Error

This error occurs when the number of active MySQL connections reaches the maximum limit defined in the MySQL configuration.

1. Check the Current Connection Limit

Run the following SQL command:

SHOW VARIABLES LIKE 'max_connections';

2. Check Current Active Connections

SHOW STATUS LIKE 'Threads_connected';

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3. Increase the MySQL Connection Limit

Option A: Temporary Increase (Immediate Effect, but Resets After Restart)

SET GLOBAL max_connections = 500;

(You can set any number as needed.)

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Option B: Permanent Increase (Recommended)

Edit the MySQL configuration file:

• Linux: /etc/my.cnf or /etc/mysql/my.cnf

• Windows: my.ini

Add or update:

[mysqld]
max_connections = 500

Then restart MySQL:

• Linux:

  sudo systemctl restart mysql

• Windows: Restart MySQL service from Services.

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4. Identify Scripts That Keep Connections Open

Sometimes the real issue is:

• Unoptimized PHP scripts

• Long-running queries

• Missing mysqli_close()

• Too many concurrent requests

Check the process list:

SHOW FULL PROCESSLIST;