Now you know all about caching and how it works. But what about speeding up the server itself?
Near the end of the previous post, I mentioned that all the caching in the world didn’t really speed up the server. This is somewhat of a lie, since if, say, you’re using Varnish to cache your site, then your visitors won’t be hitting your WordPress install, speeding it up for you to do work. But it’s not the full picture.
WordPress is big and it’s getting bigger and more complex and more impressive. So is Drupal and … well pretty much everything else. In order to make your site do more, like all that super fancy layout transformations, we have to upgrade and innovate. But then you start getting into extending these apps, like using custom fields and extra meta values to store more information so you can change search results in more impressive ways! Your site scrolls and changes backgrounds! Your site dynamically changes what products are available based on check boxes, without reloading!
What did that have to do with caching? Well … how do you cache things that aren’t static?
My coworker, Mike, likes to talk about things that should be cached and things that should never be cached. Things that have to be dynamic and run without a page refresh, like ajax and javascript, can be cached to an extent, since those plugins and Varnish will just keep the code in-line, which means it’ll still run. But when you start looking at dynamic things like shopping carts, we hit a new world and a new wall. But I’m not even talking about that level of caching. I’m talking about going back a layer into the part where WordPress (or any app) has PHP query the database. If we speed that up, caching safe content, can’t we speed things up? You bet we can!
A few years ago I talked about APC and how I was using it to speed up PHP by having it cache things. Then less than a year later, I switched to Zend and memcached. I did those things because I decided that it would be better to have my server, a workhorse, do the hard work instead of asking WordPress to do it. And this was, in general, a pretty good idea.
Memcached is an add-on for your server, and acts as “an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.” In English? It remembers what you did and can retrieve results faster because of it. Of course, you have to tell your apps to play well with it, but once you do, the backend of your site starts to speed up because, hey, caching! The Illustrated Memcache’d story is kind of an awesome explanation (the images on the archive page are broken, but the links work). And yes, I do use memcached and ZendOptomizer+ on my server, because it really does make things faster, even when two of the ten domains are having a 10k pageviews in a day.
I keep telling everyone my server isn’t overkill….
The point of that, though is the other end of speed is totally separate from your application code. When you install WordPress, you know it runs SQL and PHP, so if you can make those faster, WordPress will be faster. The same applies to speeding up Apache, maybe by putting Nginx in front of it, or maybe by tuning the hard to understand settings in httpd.conf to make sure that it elegantly handles the 300 people who come running to your site at once.
But unlike plugins, this aspect of server speed is the hard stuff. When you look at WP Super Cache, you think it’s complicated until you see W3 Total Cache. Both are amazing and awesome, but they’re giving you a ton of options and asking you to make decisions. The same is true of the servers, but now you have even more options. The world is your oyster, and we haven’t even looked at hardware.
For me, it boils down to how can I make my server do it’s job fast and efficiently. If that means I hire someone to install software to cache better, or I pay for more memory, then that’s what I do. I also trim the fat and get ride of everything I’m not using and don’t need, so my server doesn’t have to do more than it needs to. And one day, one day, I’ll be looking at nginx for everything.
