Question

I have a form with several fields that will be a fairly active. With that said there is a validation piece.

A user POST’s and the values are stored in $_SESSION variables.

On fail, the $_SESSION variables are cleared that are incorrect. I do this because the form echo’s back the previous values that are still correct, out of convience to the user.

Which is faster:

$_SESSION['variable']="";

PRO–>Less operations for each form POST
CON–>Server stores more $_SESSION variables at any given point.

unset($_SESSION['variable']);

PRO–>More operations for each form POST
CON–>Server stores less $_SESSION variables at any given point.

Thoughts?

Answer 1

You should unset() as setting it to an empty string means the session variable still exists and is pointing to a location in memory.

You shouldn’t worry at this stage which is faster, just think of what best communicates your code’s intentions.