On our servers the default max simultaneaous connections for MySQL is set to 20. This typically, is not an issue since most MYSQL connections only last a fraction of a second and having 20 in the same fraction of a second is rare. However, there are other situations that may cause this:
- Your programming code which is opening the database connection is not closing the connection. To learn more about closing a database connection please read the article.
- Your third party software is set to use persistent connections. If this is the case, you will need to consult your software’s documentation to learn how to disable pconnect.
More often than not, the second explanation (persistent connections) is the likely cause of the issue. Your software’s doumentation should address the issue and show you how to prevent the max_user_connections error.