Bug #57079 doc bug: net_write_timeout applies to more than TCP connections
Submitted: 28 Sep 2010 19:26 Modified: 28 Oct 2012 8:50
Reporter: Andrew Pimlott Email Updates:
Status: No Feedback Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.1 OS:Any
Assigned to: CPU Architecture:Any

[28 Sep 2010 19:26] Andrew Pimlott 
Description:
The documentation at http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_net_write_timeo... says that net_write_timeout "applies only to TCP/IP connections, not to connections made using Unix socket files, named pipes, or shared memory".  But that doesn't seem to be true, because I am using Unix sockets and changing this parameter obviously affects the timeout.

How to repeat:
(Using DBD::mysql): open a connection, setting mysql_use_result; open a statement handle with a query that will return a lot of data; retrieve the first row; go to sleep for 61 seconds; try to retrieve another row.  It fails with "Lost connection to MySQL server during query".  Change the script to run "set session net_write_timeout = 120" at the beginning.  Now, it succeeds.
[28 Sep 2010 19:28] Andrew Pimlott 
I forgot to say, may sure the connection uses a unix socket, obviously.  This is the default if the host parameter is left off the connection string.
[28 Sep 2010 19:35] Paul DuBois 
Sample code, please.
[28 Oct 2010 23:00] Bugs System 
No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".
[27 Sep 2012 18:41] Edward Smith 
This bug should get reactivated.... if you'll notice, someone has changed the 5.5 and 5.6 docs already.  They didn't exactly spell out what the net_write_timeout DOES apply too, but at least they took away the misleading "applies only to TCP/IP" text.
[28 Sep 2012 8:50] Stefan Hinz 
Again, could someone please provide sample code?
[29 Oct 2012 1:00] Bugs System 
No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".