MySQL ERROR 1040: Too many connections

1. About the error
2. Why do I see this error
3. Solution
4. See what's using the connections
5. Raise the limit
6. Reclaim idle connections faster
7. Fix the real cause in the app

#About the error

ERROR 1040 (HY000): Too many connections

MySQL allows a fixed number of simultaneous client connections (max_connections, default 151). Once that ceiling is reached, every new connection is rejected until an existing one closes. For a web app this surfaces as failed requests across the whole site.

#Why do I see this error

• max_connections is genuinely too low for your traffic.
• A connection leak: the application opens connections but never closes them.
• Long-running queries holding slots open, see SHOW PROCESSLIST.
• A connection pool misconfigured to exceed the server's limit.
• A real traffic spike.

#Solution

#See what's using the connections

You'll usually need an account with the SUPER privilege (MySQL reserves one extra slot for it) to get in when full:

SHOW PROCESSLIST;
SHOW STATUS WHERE Variable_name = 'Threads_connected';

If you see dozens of idle Sleep connections, that's a leak or idle sessions not being reaped, not a reason to keep raising the limit.

#Raise the limit

Temporarily, without a restart:

SET GLOBAL max_connections = 300;

Permanently, in my.cnf under [mysqld]:

[mysqld]
max_connections = 300

Then restart MySQL. Don't set this arbitrarily high, each connection consumes memory, and a too-high value can exhaust RAM and take the server down harder than the original error.

#Reclaim idle connections faster

Lower the idle timeouts so abandoned connections free their slots sooner:

wait_timeout = 120
interactive_timeout = 120

#Fix the real cause in the app

For a Laravel app, make sure you're not opening connections in a loop and that long jobs run on a queue rather than holding a web request open. A leak will exhaust any limit you set. Related: SQLSTATE[HY000] [2002] Connection refused when MySQL can't be reached at all.