If clients encounter
Too many connections
errors when attempting to connect to the
mysqld server, all available connections
are in use by other clients.
The permitted number of connections is controlled by the
variable. The default value is 151 to improve performance when
MySQL is used with the Apache Web server. To support more
max_connections to a larger
mysqld actually permits
+ 1 client connections. The extra connection is reserved for
use by accounts that have the
CONNECTION_ADMIN privilege (or
privilege). By granting the privilege to administrators and
not to normal users (who should not need it), an administrator
can connect to the server and use
PROCESSLIST to diagnose problems even if the maximum
number of unprivileged clients are connected. See
Section 220.127.116.11, “SHOW PROCESSLIST Statement”.
The server also permits administrative connections on a dedicated interface. For more information about how the server handles client connections, see Section 18.104.22.168, “Connection Interfaces”.