How do I change MySQL wait_timeout in production environment at runtime?

Question

I'm running Windows, IIS, MySQL, PHP.

In my.ini under [mysqld] the value for wait_timeout is set to 60.

wait_timeout = 60 

But when I execute the following:

show variables like 'wait_timeout'; 

It shows me that the value is 28800, which I know is the default.

So I tried to set the value by executing the following:

SET GLOBAL wait_timeout = 60; 

But this doesn't seem to work. MySql Workbench tells me "0 rows(s) affected" and when I execute show variables like 'wait_timeout' it still tells me that the value is 28800.

I've also checked interactive_timeout and the story is the same. The value is 28800 and I can't change it.

What am I missing here?

Answer 1

The answer is to set the value without the GLOBAL keyword.

SET wait_timeout = 60; 

Answer 2

GLOBAL setting are copied into your SESSION settings when you connect. Use either of these syntaxes:

SET @@... = ...; SET SESSION ... = ...; 

wait_timeout refers to how soon before you will be disconnected. Is that what you want?

Furthermore, there is some confusion over "batch" versus "interactive" timeout. Good look.