Mysql - when increase 'max_connections', what other paramters to adjust accordingly?

Question

I know some memory / cache / open file related params should be adjusted accordingly.

But after searching for quite a while, didn't found a comprehensive guide.

Say, mysql 8 is in use, running on Linux, and trying to change max_connections to 400, the database is using innodb engine, could you give a list of other parameters, and their new values to adjust to, in common.

Answer 1

The main setting is innodb_buffer_pool_size. It should be set to about 70% of available RAM if you have more than 4GB of RAM.

If you need more than the default 151 for max_connections it is worth looking into whether the client(s) are allowing too many connections. It is better to reduce the load from that size.

A common problem is open_files_limit. It comes from the OS's ulimit may be at a painfully low 1024. That should be fixed in the OS.

There are no other "likely" settings to check on, especially with MySQL 8.0.

There are STATUS values that can help tuning busy systems. See this for guidance in that help: http://mysql.rjweb.org/doc.php/mysql_analysis#tuning