Oracle 5.0 Reference Manual page 2975

You can also get strange problems with large packets if you are using large
given
mysqld
ulimit -d 256000
C.5.2.11. Communication Errors and Aborted Connections
If connection problems occur such as communication errors or aborted connections, use these sources
of information to diagnose problems:
• The error log. See
• The general query log. See
• The
Aborted_xxx
If you start the server with the
your error log:
010301 14:38:23
'users' user: 'josh'
If a client successfully connects but later disconnects improperly or is terminated, the server increments
the
Aborted_clients
error log. The cause can be any of the following:
• The client program did not call
• The client had been sleeping more than
seconds without issuing any requests to the server. See
• The client program ended abruptly in the middle of a data transfer.
If a client is unable even to connect, the server increments the
variable. Unsuccessful connection attempts can occur for the following reasons:
• A client does not have privileges to connect to a database.
• A client uses an incorrect password.
• A connection packet does not contain the right information.
• It takes more than
"Server System
If these kinds of things happen, it might indicate that someone is trying to break into your server!
Messages for these types of problems are logged to the general query log if it is enabled.
Other reasons for problems with aborted clients or aborted connections:
• The
max_allowed_packet
you have allocated for mysqld. See
• 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 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.
• Faulty Ethernets, hubs, switches, cables, and so forth. This can be diagnosed properly only by
replacing hardware.
Common Errors When Using MySQL Programs
access to enough memory to handle the query. If you suspect this is the case, try adding
to the beginning of the
Section 5.2.1, "The Error
Section 5.2.2, "The General Query
status variables. See
--log-warnings
Aborted connection 854 to db:
[523] status variable, and logs an
mysql_close()
connect_timeout
Variables".
[466] variable value is too small or queries require more memory than
script and restarting mysqld.
mysqld_safe
Log".
Section 5.1.6, "Server Status
[414] option, you might find messages like this in
Aborted connection
before exiting.
[506]
wait_timeout
Section 5.1.4, "Server System
[445] seconds to get a connect packet. See
Section C.5.2.10, "Packet Too
2955
values but have not
BLOB
Log".
Variables".
message to the
or
interactive_timeout
[523]
Aborted_connects
Large".
[457]
Variables".
status
Section 5.1.4,