Find mysql open connections
The MySQL show status command
You can show MySQL open database connections (and other MySQL
database parameters) using the MySQL show status command, like this:
mysql> show status like 'Conn%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Connections | 8 |
+---------------+-------+
1 row in set (0.00 sec)
mysql> show status like '%onn%';
+--------------------------+-------+
| Variable_name | Value |
+--------------------------+-------+
| Aborted_connects | 0 |
| Connections | 8 |
| Max_used_connections | 4 |
| Ssl_client_connects | 0 |
| Ssl_connect_renegotiates | 0 |
| Ssl_finished_connects | 0 |
| Threads_connected | 4 |
+--------------------------+-------+
7 rows in set (0.00 sec)
All those rows and values that are printed out correspond to MySQL variables that you can look at. Notice that I use
like 'Conn%'in
the first example to show variables that look like "Connection", then
got a little wiser in my second MySQL show status query.
MySQL show processlist
Here's what my MySQL processlist looks like when I had my Java application actively running under Tomcat:
mysql> show processlist;
+----+------+-----------------+--------+---------+------+-------+------------------+
| Id | User | Host | db | Command | Time | State | Info |
+----+------+-----------------+--------+---------+------+-------+------------------+
| 3 | root | localhost | webapp | Query | 0 | NULL | show processlist |
| 5 | root | localhost:61704 | webapp | Sleep | 208 | | NULL |
| 6 | root | localhost:61705 | webapp | Sleep | 208 | | NULL |
| 7 | root | localhost:61706 | webapp | Sleep | 208 | | NULL |
+----+------+-----------------+--------+---------+------+-------+------------------+
4 rows in set (0.00 sec)
