Total Thread Connections

show status where variable_name = 'threads_connected';

Max Connections

The connected threads are limited by max_connections:

show variables like 'max_connections';  
SET GLOBAL max_connections = 350;

Connection Timeout

The connected threads timeout and are closed if they are inactive for too long.

show variables like 'wait_timeout';

-- applies to new connection sessions only - 20 minutes (default 28800 is 8 hours)
SET GLOBAL wait_timeout = 1200;  -- seconds

Running Threads

show status where variable_name = 'threads_running';

Top Hosts

If you want to know which hosts and users are taking up the most open connections quickly and easily:

-- display the number of connections by host for all users (ignores client port)
select SUBSTRING_INDEX(`host`, ':', 1) jHost,
       count(distinct `user`) 'user cnt' ,
       count(SUBSTRING_INDEX(`host`, ':', 1)) 'host cnt',
       SUM(`time`)
from information_schema.processlist
group by `jHost`
 order by 3 DESC,  3 desc;

Top Hosts By User

-- display the number of connections by host and user (ignores client port)
select SUBSTRING_INDEX(`host`, ':', 1) jHost,
		`user`,
       count(distinct `user`),
       count(SUBSTRING_INDEX(`host`, ':', 1)),
       SUM(`time`)
from information_schema.processlist
group by `jHost`, `user`
 order by 4 DESC,  5 desc;

Support