Submitted by Guaka on January 25, 2010 - 01:50
Sites that show up quickly on a user's screen tend to keep the user's attention for longer and also rank better in Google. So when listening to the excellent Lullabot Podcast 80: Top 40 Drupal Modules Revisited I was caught by Drupal experts stating that Memcache would even speed up your site if it's not a high traffic site. It could off-load the database. I decided to give it a try on a relatively low traffic site of one of my clients. The site is already being served by nginx so the load times are already pretty good.
When setting up the experimentation I was a bit confused by the thorough but chaotic instruction to set up memcache. I ran into a problem setting up PECL memcache:
It could be that I'd have to tweak some memcache settings, or run longer tests, but I think these numbers are clear enough: memcache made my site slower instead of faster!
$ sudo pecl install memcache downloading memcache-2.2.5.tgz ... Starting to download memcache-2.2.5.tgz (35,981 bytes) ..........done: 35,981 bytes 11 source files, building running: phpize Configuring for: PHP Api Version: 20041225 Zend Module Api No: 20060613 Zend Extension Api No: 220060519 shtool at '/tmp/pear/temp/memcache/build/shtool' does not exist or is not executable. Make sure that the file exists and is executable and then rerun this script. ERROR: `phpize' failedSince I run Debian I solved this by running
apt-get install php5-memcache
instead.
I restarted php-fastcgi (needed for nginx) and added $conf['cache_inc'] ='sites/all/modules/memcache/memcache.db.inc';
to settings.php.
Then I ran some tests in Hammerhead. Not on the front page since there is an embedded Youtube video. I chose a page without any external elements. I was a bit confused at first, and ran several short tests. I forgot to log out and the memcache module was adding a lot of extra information in the bottom. I thought that was the reason that my site was a lot slower with memcache than without it. So I logged out and tried again:
count | latest | median | avg | |
---|---|---|---|---|
empty cache with memcache | 4 | 1449 | 1449 | 1759 |
primed cache with memcache | 4 | 1277 | 1186 | 1184 |
empty cache without memcache | 4 | 1239 | 1283 | 1483 |
primed cache without memcache | 4 | 1014 | 900 | 950 |