MySQL: Too many connection errors.

When user trying to connect MySQL Database, he got below error

ERROR 1040 (hy000): Too many connections
By looking the error we can see that the max_connections got exhausted. You can check the connection info by running below commands.

-- To find max_connections value run below command
SHOW VARIABLES LIKE '%max_connections%';

-- To see the all processes and connections run below command
SHOW FULL PROCESSLIST;

Note that when you get this error you will be able to login using root. Becoz My SQL by default will consider maximum allowed connections as MAX_CONNECTIONS +1 for super user.

But if you have used root to connect to any other app you will not able to connect to run the above commands. That means you should use root for only Administration purpose only.

You can run below command to change the MAX_CONNECTIONS

SET GLOBAL max_connections = 200;
But note that you need to find out is there any application issue which is creating more connections and causing this issue and fix that later.

Regards
Satishbabu Gunukula, Oracle ACE
http://oracleracexpert.com