User perf_inventory already has more than 'max _ user_connections 'active connections

Caused by: COM. MySQL. JDBC. Exceptions. jdbc4.mysqlsyntaxerrorexception: User perf_inventory already has more than 'max _ user_connections'
Active connections indicates that the user has reached the maximum number of connections and cannot connect to more connections.
Max_connections
The maximum number of connections is provided for an instance. What if there are more connections?

mysql> show variables like "%connections";          +----------------------+-------+| Variable_name        | Value |+----------------------+-------+| max_connections      | 3000  || max_user_connections | 0     |+----------------------+-------+

mysql> select @@max_user_connections;+------------------------+| @@max_user_connections |+------------------------+|                      0 |+------------------------+

How can I check how many connections a user has used?

Mysql> show full processlist; # view User + ---- + ------ + ----------------- + ------ + --------- + ------ + ------- + ----------------------- + | ID | user | host | dB | command | time | state | info | + ---- + ------ + ----------------- + ------ + --------- + ------ + ------- + --------------------- + | 4 | root | localhost: 65325 | null | query | 1 | null | show full processlist | + ---- + ------ + ----------------- + ------ + --------- + ------ + ------- + ----------------------- + 1 row in SET (0.06 Sec) mysql> show processlist; + ---- + ------ + --------------- + ------ + --------- + ------ + ------- + ------------------- + | ID | user | host | dB | command | time | state | info | + ---- + ------ + ----------------- + ------ + --------- + ------ + ------- + ----------------- + | 4 | root | localhost: 65325 | null | query | 0 | null | show processlist | + ---- + ------ + ----------------- + ------ + --------- + ------ + ------- + --------------------- +