Default maximum concurrent connections a mysql database server can handle is set as 100. If you require your mysql database server to serve higher number of concurrent connects than 100, you can set this on the fly as bellow without restarting the mysqld service. Make sure you have enough hardware resources (Generally RAM) to accommodate more connections.
To check current maximum concurrent connections,
mysql> show variables like “max_connections”;
+—————--+——-+
| Variable_name | Value |
+—————--+——-+
| max_connections | 100 |
+—————--+——-+
1 row in set (0.01 sec)