[Mediawiki-l] How to "activate" a new extension

[Alok Watve]

Hi

I am a total n00b to mediaWiki. I am writing a new extension to
dynamically generate an SVG file. I have written the extension and
copied the files in the right places.
But mediaWiki does not seem to pick up my extension. DO I need to
restart the apache server or something like that in order to make sure
my change in LocalSettings.php is picked up.

What I don't understand (and I do not think is documented very well )
is how does mediawiki know that the file LocalSettings.php has changed
and needs to be re-loaded.

Alok