Question

I’m running a standard configuration of Apache with PHP.
I’m wondering what happens when a client requests a page that causes a PHP script to execute, then the client kills the request from the server, before the script finishes.
Does Apache kill the script in some way, or is it allowed to complete nonetheless?

Answer 1

The documentation answers this:

When a PHP script is running normally
the NORMAL state, is active. If the
remote client disconnects the ABORTED
state flag is turned on. A remote
client disconnect is usually caused by
the user hitting his STOP button. If
the PHP-imposed time limit (see
set_time_limit()) is hit, the TIMEOUT
state flag is turned on.

You can decide whether or not you want
a client disconnect to cause your
script to be aborted. Sometimes it is
handy to always have your scripts run
to completion even if there is no
remote browser receiving the output.
The default behaviour is however for
your script to be aborted when the
remote client disconnects. This
behaviour can be set via the
ignore_user_abort php.ini directive as
well as through the corresponding
php_value ignore_user_abort Apache
httpd.conf directive or with the
ignore_user_abort() function. If you
do not tell PHP to ignore a user abort
and the user aborts, your script will
terminate.

If you want to tell the remote client that the script is complete, but continue post-request processing nonetheless, look at this question/answer.