The World of MySQL & MariaDB

How to Restart MySQL on Linux and Windows: Step-by-Step Guide

  • 2025-09-08
  • OS
OS
目次

1. Why Restarting MySQL Is Necessary

Restarting MySQL is often required during system operations. It is especially recommended after configuration changes to apply new settings or when performance degradation is observed. Since restarting temporarily halts database connections, careful planning is essential.

Cases When Restart Is Required

  • Applying Configuration Changes: When modifying configuration files such as my.cnf or my.ini, restarting MySQL is required to apply the changes.
  • Fixing Issues or Errors: If abnormal behavior is observed in the server, restarting can reset the system and restore normal operations.
  • Releasing Resources: On servers running for long periods, memory fragmentation or accumulated resource usage can cause performance degradation. Restarting clears these resources and improves server performance.

2. Basic MySQL Operations

Understanding the basic operations related to restarting MySQL is essential for database administrators. In particular, it is important to know how to start, stop, and restart the service.

Starting MySQL

If MySQL is stopped, you can start it with the following command:
sudo service mysqld start
Alternatively, this command can also be used:
mysql.server start
When executed successfully, a message saying “SUCCESS!” will confirm that MySQL has started correctly.

Stopping MySQL

To stop MySQL, use the following command:
sudo service mysqld stop
This command stops the server and displays a “SUCCESS!” message.

Restarting MySQL

Restarting means stopping MySQL and immediately starting it again.
sudo service mysqld restart
Alternatively, you can also use:
mysql.server restart
This command stops the MySQL server and then starts it again immediately.

3. How to Restart MySQL (Linux Environment)

Restart Procedure

In Linux environments, restarting the MySQL server is simple. Use the following command:
sudo service mysqld restart
Or alternatively:
mysql.server restart
When executed successfully, the message “SUCCESS!” will confirm that the restart was completed.

Checking Error Messages

If an error occurs during restart, check the displayed message to identify the issue. Common errors include permission issues or port conflicts.

Checking Log Files

For troubleshooting, checking MySQL’s log files is effective. Logs are usually stored in /var/log/mysqld.log. Since detailed error information is recorded, review this file if the restart fails.

4. How to Restart MySQL (Windows Environment)

Restarting with the Services Management Tool

In Windows environments, restarting MySQL can be easily done using the GUI-based Services Management Tool.
  1. Open the Windows “Services” management tool (type services.msc in “Run”).
  2. Find the “MySQL” service in the list, right-click, and select “Restart.”

Restarting with Command Prompt

You can also restart MySQL using the Command Prompt:
net stop mysql
net start mysql
This command stops the MySQL service and then restarts it immediately.

5. Case Studies Requiring Restart

Applying Configuration Changes

To apply modifications made to my.cnf or my.ini files, a restart is necessary. For example, when changing memory usage or maximum connection limits, restarting ensures the new settings are applied.

Improving Performance

If server performance declines, restarting clears memory and cache, allowing resources to be used efficiently again. Restarting can serve as a temporary solution to performance issues.

6. Troubleshooting and FAQ

What to Do If Restart Fails

If problems occur during restart, common causes include:
  • Insufficient Permissions: Restarting MySQL requires administrator privileges. If sudo is not used, errors will occur.
  • Port Conflicts: If the port used by MySQL (default: 3306) conflicts with another service, restart may fail. In this case, stop the conflicting service or change MySQL’s port.

Frequently Asked Questions (FAQ)

  • Will restarting cause data loss? Normally, data will not be lost during a restart, but unfinished transactions may be rolled back.
  • Do I always need to restart after configuration changes? Some settings apply without restarting, but most configuration changes require a restart.

7. Summary and Next Steps

Restarting MySQL is essential for applying configuration changes and improving performance. In particular, when issues occur or server load increases, restarting often provides a quick solution. By understanding basic restart procedures, administrators can incorporate this into routine management tasks. As a next step, implementing regular maintenance and backup strategies will help ensure more reliable database operations.