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:
$ 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' failed
Since 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 |
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!