Do you already have another mysqld server running on port: 33306?

Introduction

MySQL is one of the most popular open-source relational database management systems. It is widely used for storing, managing, and retrieving data in various applications. Sometimes, when working with MySQL, you may encounter an error message like "Do you already have another mysqld server running on port: 33306?" This error usually occurs when there is already an instance of the MySQL server running on the specified port, and you're trying to start another instance.

In this article, we will explore the reasons behind this error and provide solutions to resolve it.

Understanding the Error

Before we dive into the solutions, let's understand the error message and its implications. The error message states that another mysqld server is already running on port 33306. The mysqld process is responsible for running the MySQL server. Each process requires a unique port number to listen for incoming connections. If there is already a process listening on the specified port, the new instance cannot start.

Reason for the Error

There could be several reasons why another mysqld server is already running on the specified port:

  1. Multiple instances: You might have accidentally started multiple instances of MySQL server, and they are conflicting with each other.
  2. Improper shutdown: If MySQL server was not properly stopped or terminated, it might still be running in the background.
  3. System restart: After a system restart, the MySQL server might automatically start if it is configured to do so.

Now, let's move on to the solutions to resolve this error.

Solution 1: Stop the Existing MySQL Server

The first solution is to stop the existing MySQL server that is running on the specified port. This can be done through the command line or using the MySQL Workbench.

Here's an example of how to stop the MySQL server using the command line:

sudo systemctl stop mysql

After stopping the server, you can start a new instance of MySQL server on the desired port without encountering the error.

Solution 2: Change the Port Number

If stopping the existing MySQL server is not an option, you can try changing the port number for the new instance. By default, MySQL server listens on port 3306. However, you can specify a different port number in the MySQL configuration file.

Here's an example of how to change the port number in the MySQL configuration file (my.cnf):

nano /etc/mysql/my.cnf

Locate the port parameter under the [mysqld] section and modify it with the desired port number, such as 33306. Save the changes and restart the MySQL server.

sudo systemctl restart mysql

Now, you should be able to start the new instance of MySQL server without any conflicts.

Conclusion

The error message "Do you already have another mysqld server running on port: 33306?" occurs when there is already a running instance of MySQL server on the specified port. This article provided two solutions to resolve the error: stopping the existing MySQL server or changing the port number for the new instance. By following these solutions, you can successfully start a new instance of MySQL server without encountering any conflicts.

Remember to ensure that there is only one MySQL server running on a given port to avoid unnecessary errors and conflicts.

stateDiagram
    [*] --> Existing Server
    Existing Server --> Stop Existing Server
    Stop Existing Server --> [*]
    Existing Server --> Change Port Number
    Change Port Number --> [*]

gantt
    title MySQL Server Startup Process
    dateFormat  YYYY-MM-DD
    section Start the Existing MySQL Server
    Stop Existing Server        : 2022-01-01, 2d
    section Start the New MySQL Server
    Change Port Number          : 2022-01-03, 1d

I hope this article helped you understand why the error occurs and how to resolve it. Happy coding with MySQL!