How to check time spent by mod_rewrite when rewrite urls? - apache

Question

My question is simple:
Is it possible to know the time elapsed when apache mod_rewrite rewrite urls ?
My site has about 20 million requests/month.
In this case, I want to know the time spent in these rules.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
# Remove Multiple slashes in betweeen
RewriteCond %{REQUEST_URI} ^(.*)//(.*)$
RewriteRule . %1/%2 [R=301,L]
# Send everything to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ some_path/index.php/$1 [L]
</IfModule>
Thanks in advance

Answer 1

Move rewriting to VirtualHost configuration if possible, so regular expressions are not compiled for each request in .htaccess.
For example, for Apache, in httpd.conf place your content of .htaccess like this:
<Directory /www/htdocs/example>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
# Remove Multiple slashes in betweeen
RewriteCond %{REQUEST_URI} ^(.*)//(.*)$
RewriteRule . %1/%2 [R=301,L]
# Send everything to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ some_path/index.php/$1 [L]
</IfModule>
</Directory>

Answer 2

You could check the "waiting" time in Firebug or other Browser tools to check how much time is spent between the request and your browser actually receives data.
Redirecting to static ressources would of course be better to avoid evaluating the time PHP takes to process the request.
Of coure it will still include the time Apache normally spends treating the request and you probably want to test both scenarios: with redirect and without.
BTW, if you're looking to optimize these, you could try replacing this :
RewriteCond %{REQUEST_URI} ^(.*)//(.*)$
RewriteRule . %1/%2 [R=301,L]
With this :
RewriteRule ^(.*)//(.*)$ $1/$2 [R=301,L]
There's no real need to use this kind of rewritecond alone, a more complex rewrite rule is enough.
Also,
RewriteRule ^(.*)$ some_path/index.php/$1 [L]
Can be replaced with
RewriteRule (.*) some_path/index.php/$1 [L]
Starting and ending character won't be sent in $1 so it can be included in the rule, hence simplifying it.