The server error log can be a useful source of information
about connection problems. See 「エラー ログ」. If
you start the server with the
option, you might find messages like this in your error log:
010301 14:38:23 Aborted connection 854 to db: 'users' user: 'josh'
Aborted connections messages appear in
the error log, the cause can be any of the following:
The client program did not call
mysql_close() before exiting.
The client had been sleeping more than
interactive_timeout seconds without
issuing any requests to the server. See
The client program ended abruptly in the middle of a data transfer.
When any of these things happen, the server increments the
Aborted_clients status variable.
The server increments the
status variable when the following things happen:
A client doesn't have privileges to connect to a database.
A client uses an incorrect password.
A connection packet doesn't contain the right information.
It takes more than
seconds to get a connect packet. See
If these kinds of things happen, it might indicate that someone is trying to break into your server!
For reasons of security and performance the advisors
provided by the MySQL Network Monitoring and Advisory
Service pay special attention to the
Aborted_connections status variable. For
more information see,
Other reasons for problems with aborted clients or aborted connections:
Use of Ethernet protocol with Linux, both half and full duplex. Many Linux Ethernet drivers have this bug. You should test for this bug by transferring a huge file via FTP between the client and server machines. If a transfer goes in burst-pause-burst-pause mode, you are experiencing a Linux duplex syndrome. The only solution is switching the duplex mode for both your network card and hub/switch to either full duplex or to half duplex and testing the results to determine the best setting.
Some problem with the thread library that causes interrupts on reads.
Badly configured TCP/IP.
Faulty Ethernets, hubs, switches, cables, and so forth. This can be diagnosed properly only by replacing hardware.
max_allowed_packet variable value
is too small or queries require more memory than you have
allocated for mysqld. See
Packet too large」.
See also 「
MySQL server has gone away」.