WordPress MU

If a theme doesn't have a search.php file which file does it fall back on to display the search results. Is it page.php?

index.php

http://codex.wordpress.org/File:Template_Hierarchy.png

Ok thanks for that.

Second question:

Is there any performance impact on changing :

while (have_posts()) { the_post();

to

while (have_posts()) { the_post(); switch_to_blog($post->blog_id);

with the corresponding endwhile modified with restore_current_blog

in the index.php file?

I'm working on integrating wpsearchmu into a whole number of templates and some don't have search.php files

Not sure. Maybe try outputting this in your footer.

<!-- <?php echo get_num_queries(); ?> queries. <?php timer_stop(1); ?> seconds. -->

It's commented just so that if your site is public you will only see it by doing a view source.

Hmm

Without the switching:

<!-- 111 queries. 2.194 seconds. -->

with the switching:

<!-- 111 queries. 2.061 seconds. -->

So it makes no real difference at all

That was my guess, but real numbers are better than guessing.