https://blog.csdn.net/lovemysea/article/details/73834917
Method 1: Enter the MYSQL installation directory and open the MYSQL configuration file my.ini or my.cnf to find max_connections=100 and change it to max_connections=1000. Restart MYSQL in the service.
Method 2: The maximum number of MySQL connections is 100 by default. Client login: mysql -uusername -ppassword
Set the new maximum number of connections to 200: mysql> set GLOBAL max_connections=200
Display the currently running Query: mysql> show processlist
Display the current status: mysql> show status
Exit the client: mysql> exit
to view the current maximum number of connections : mysqladmin -uusername -ppassword variables
Method 3: Take the manually compiled version of mysql 5.0.33 under centos 4.4 as an example:
vi /usr/local/mysql/bin/mysqld_safe
Find safe_mysqld and edit it, find the two lines where mysqld starts, Add the parameter after:
-O max_connections=1500