How to Increase MySQL Max Connections and Resolve Connection Limit Errors

When a Jira error indicated “too many database connections”, the issue was traced to MySQL’s max_connections setting.

By logging into MySQL and running show variables like '%max_connections%'; you can see the current limit (default 151 for MySQL 5.5‑5.7, 100 for 5.0, etc.).

To raise the limit, edit /etc/my.cnf (or the appropriate MySQL configuration file) and add max_connections=1000 under the [mysqld] section, then restart the MySQL service.

Alternative methods include:

Setting the global variable at runtime: set global max_connections = 200; and verifying with show variables like '%max_connections%';

Recompiling MySQL after modifying the source constant in mysqld.cc (change the default value and rebuild).

Adjusting the mysqld_safe startup script to pass -O max_connections=1500 .

Different MySQL versions have different default limits and maximum caps (e.g., 151 default with a hard limit of 100 000 for 5.5‑5.7, 100 default with a limit of 16 384 for 5.0, etc.).