MySQL 8 Administrator???s Guide

Too many connections

This error indicates that all available connection are in use for other client connections. The max_connections is the system variable that controls the number of connections to the server. The default value for the maximum number of connections is 151. We can set a larger value than 151 for the max_connections system variable to support more connections than 151.

The mysqld server process actually allows one more than max_connections (max_connections + 1) value clients to connect. The additional one connection is kept reserved for accounts with CONNECTION_ADMIN or the SUPER privilege. The privilege can be granted to the administrators with access to the PROCESS privilege. With this access, the administrator can connect ...