If you are a MySQL user, you may have come across the error message "Can't open the mysql.plugin table. Please run mysql_upgrade to create it" when trying to start or upgrade your MySQL server. This error can happen for various reasons, but thankfully, it's usually easy to fix. In this guide, we'll walk you through the steps to troubleshoot this error and get your MySQL server up and running again.
What is the "Can't open the mysql.plugin table" error?
The "Can't open the mysql.plugin table" error is a common error message for MySQL users. It usually appears when trying to start or upgrade the MySQL server. The error message indicates that the MySQL server is unable to access the mysql.plugin table, which is required for the proper functioning of the server.
Why does the "Can't open the mysql.plugin table" error occur?
The "Can't open the mysql.plugin table" error can occur for various reasons. Some of the most common reasons include:
- Corrupted or missing mysql.plugin table
- Incorrect permissions on the mysql.plugin table
- Incorrect MySQL version
- Incomplete MySQL installation
How to fix the "Can't open the mysql.plugin table" error?
Here are the steps to fix the "Can't open the mysql.plugin table" error by running mysql_upgrade:
Open your terminal or command prompt.
Type the following command to stop the MySQL server:
sudo service mysql stop
Note: If you are not using Ubuntu, the command may be different. Please refer to your system's documentation for the correct command to stop the MySQL server.
Type the following command to upgrade your MySQL server:
sudo mysql_upgrade -u root -p
Note: Replace "root" with your MySQL username if you are not using the root user.
Enter your MySQL password when prompted and press Enter.
Wait for the upgrade process to complete.
Type the following command to start the MySQL server:
sudo service mysql start
Check if the error has been resolved by running the following command:
sudo systemctl status mysql
If the status indicates that the MySQL server is running, then the error has been resolved.
FAQ
Q1. What is the mysql.plugin table?
The mysql.plugin table is a system table in MySQL that stores information about plugins that are installed on the server.
Q2. Do I need to run mysql_upgrade every time I upgrade MySQL?
It is recommended to run mysql_upgrade every time you upgrade MySQL to ensure that the system tables are up to date.
Q3. What if I don't have root access to the MySQL server?
If you don't have root access to the MySQL server, you can ask your system administrator to run the mysql_upgrade command for you.
Q4. What if mysql_upgrade doesn't work?
If mysql_upgrade doesn't work, you can try the following steps:
- Make sure that you are logged in as the root user or have sufficient privileges to run mysql_upgrade.
- Check your MySQL version and make sure that it's compatible with mysql_upgrade.
- Check your MySQL installation and make sure that it's complete and not corrupted.
Q5. Can I run mysql_upgrade without stopping the MySQL server?
No, you need to stop the MySQL server before running mysql_upgrade to ensure that there are no active connections to the server during the upgrade process.