Question

Recently I’ve discovered that I have too many connections in my MySQL database:

mysql> show status like 'Conn%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Connections   | 39    |
+---------------+-------+
1 row in set (0.00 sec)

mysql> show full processlist;
+----+-------+-----------+--------+---------+------+-------+-----------------------+
| Id | User  | Host      | db     | Command | Time | State | Info                  |
+----+-------+-----------+--------+---------+------+-------+-----------------------+
| 38 | enrmr | localhost | cakedb | Query   |    0 | NULL  | show full processlist |
+----+-------+-----------+--------+---------+------+-------+-----------------------+

I’ve recently installed CakePHP and every time I refresh the main page (F5) the number of connections is incremented in one.
Also if I restart again mysql the number of connections al still 39.

My netstat output

netstat -n -a | grep 3306
tcp        0      0 127.0.0.1:3306          0.0.0.0:*               ESCUCHAR   

I suppose that I have something like ‘mysql zombies connections’. How can I kill them? And how I can stop the creations of new connections every time the web page is refreshed? (Can I only have one connection ?)
Thanks.

Answer 1

First, Connections is an incremental counter, it’s not current connections. It’s total number of connections that were established and/or closed to MySQL instance.

If you want current connections look at Threads_connected, rather than Connections.

Secondly, 39 connections is not much, even if it’s a total number of connected threads. It all depends on the application, although just one CakePHP instance will probably utilize just one thread.