Redis Object Cache for WordPress, the Accidental Effect of PHP 5.5

Last week, I went a little upgrade-crazy with the VPS that hosts this site. With SPDY 3.1 support in nginx 1.5, I upgraded. I also bumped PHP from 5.4 to 5.5.

The latter change is significant because PHP 5.5 drops support for APC, and I was using APC for both opcode caching at the PHP level and object caching at the WordPress level (thanks to Jaquith’s plugin). Since I’d lost my object cache, I’d also lost my page cache because I was using Batcache. Nice job, Erick.

Almost a year ago, I contributed two small changes to Eric Mann’s WordPress Redis Backend plugin. With Redis already running on my VPS for reasons unrelated to WordPress, it seemed an obvious choice over competing persistent caching options.

I spent some time updating Eric’s plugin (see https://github.com/ethitter/wordpress-redis-backend/commits/master for the fun I’ve had) and sent a massive pull request back with my changes. I’ve been using the plugin for a few days now without incident, though I wouldn’t rush to switch over just yet unless you’re adventurous. I’d watch Eric’s repo if you’re interested in what comes of my efforts.