When a client or application unable to connect to mysql, the mysql server increments the Aborted_connects status variable. Unsuccessful connection attempts can occur for the following reasons:
- ASL is attempting to connect to the tortix database, but has no privileges to access the database
- ASL is configured to use the wrong password to log into its database
- It takes more than connect_timeout seconds to obtain a connect packet. (This is the most common cause)
This can also occur if the mysql connection is improperly disconnect or is terminated, in which case the mysql server increments the Aborted_clients status variable, and logs an Aborted connection message to the error log. The cause can be any of the following:
- The client connection to the mysql server has been sleeping more than wait_timeout or interactive_timeout seconds without issuing any requests to the server.
- A component in ASL that writes to the database was abruptly terminated in the middle of a data transfer.
- The max_allowed_packet variable value is too small or queries require more memory than you have allocated for mysqld.
- Some Linux Ethernet drivers have a bug that can cause connections to abruptly close. You should test for this bug by transferring a huge file using FTP between the client and server machines. If a transfer goes in burst-pause-burst-pause mode, you are experiencing a Linux duplex syndrome. Switch the duplex mode for both your network card and hub/switch to either full duplex or to half duplex and test the results to determine the best setting.
- A problem with the thread library that causes interrupts on reads.
- Badly configured TCP/IP.
- For remote mysql servers, this can also occur does to network problems, and bad hardware include but not limited to hubs, switches, cables, and so forth. This can be diagnosed properly only by replacing hardware.