mysql数据库连接过多

Question

I have a shell script to execute some query in mysql database and process the results and send mail accordingly. The script runs 24X7 in each 15 minutes. Inside the shell script I am simply connecting to the db using the command 'mysql -uusername -ppassword database -s -N -e "Some query goes here"

All I want to know is that, does this script have to do something with the db connection leak, since I am executing this script forever. When I execute the following query I can see that each time the Connections value goes up by one in each 15 minutes. show status like '%Con%';

+----------------------------------------+-------+
| Variable_name                          | Value |
+----------------------------------------+-------+
| Aborted_connects                       | 4     |
| Com_show_contributors                  | 0     |
| Connections                            | 804   |
| Max_used_connections                   | 152   |
| Performance_schema_cond_classes_lost   | 0     |
| Performance_schema_cond_instances_lost | 0     |
| Ssl_client_connects                    | 0     |
| Ssl_connect_renegotiates               | 0     |
| Ssl_finished_connects                  | 0     |
| Threads_connected                      | 14    |
+----------------------------------------+-------+

Does it crash at some point of time?. Because the value never comes down. I know the value indicates the total number of connections present to the db. However Max_used_connections remains same. Or is there a way to close the db connection from shell script?

Answer 1

As MySQL documentation on the connections server status variable says:

The number of connection attempts (successful or not) to the MySQL server.

So, this is a statistical number showing the number of connection attempts since the last restart of the MySQL server.

The threads_connected status variable shows the number of currently open connections (14 in your case). If this status variable equals to the max_connections server SYSTEM variable , then you will start receiving too many connections error message.