too many session variables.

[bleak26]

what would happen if i created session variables in php 5 and did not destroy them and then many sessions were used in a short period, leaving many varables undestroyed.

what is the recomended methord for destroying a single session.

is there a good methord to release all session variables universally.

[coopster]

Out of the box sessions are text files that are stored on the server's filesystem in the directory specified in your php.ini session directive. So, each time you add a session variable, more text gets added to that related file on your server. When a user logs out of a session it is a good practice to clear it out and destroy.

$_SESSION = array(); 
session_destroy();

[bleak26]

Please can you tell me will this kill the session value called expanded?
Will it do more or will it do something else?

$_SESSION['expanded'] = array();

[coopster]

That will set the 'expanded' index of the $_SESSION superglobal array to a blank array. In effect, you haven't really *killed* it but initialized it to a blank value. To get rid of it you can unset() [php.net] it. I would not unset() the $_SESSION superglobal though, to initialize the entire superglobal array use the method I have demonstrated.