Persistent Object Cache

One of the big recent additions is the Persistent Object Cache. Objects such as pages, categories, options, and users are saved locally to disk so that WP doesn’t have to make a trip to the database. The object cache is completely pluggable, allowing hosts to tailor the cache to their particular usage and needs. Folks on the hackers and testers lists have been shaking out the bugs. The cache is looking pretty stable as of now.

18 thoughts on “Persistent Object Cache

  1. I get modest improvements of a few percent in my Apache bench benchmarks. I think the persistent cache will be of most use to WPMU. Regardless, the resulting code cleanups from having a clearly defined cache API and the ability to replace the cache implementation wholesale are worthwhile improvements. I’d like to see backends for memcached and other caching deamons so that we can compare numbers.


  2. Is there an easy way to clear this cache? I did an upgrade (to some of the latest SVN) and had to turn off the caching because it is storing the db_version as nothing/blank somewhere, so it’s not matching the version in version.php and then WP doesn’t display anything.


  3. I’ve been hearing of and seeing some problems with mod_rewrite
    permalinks and the new object caching code. I haven’t gotten a chance
    to look too far into where this might be coming from yet, but its
    something to keep your eyes open for.


  4. Seems like life is gonna be easier (at least for some people :)) )
    …. er… hopefully…. in the nearest future. But are you sure that all the OS will be able to make it pluggable?


  5. […] I could not for the life of my figure out why until I looked at the source code for wpgetsettings() and saw something about caching. Turns out one of WordPress 2.0’s great new features is Persistent Object Caching which means pages and options can be cached on disk, so when they are served up the server doesn’t have to check their value in the database. This is all great if the cache is correctly updated when these options are changed, but for some reason, it wasn’t in this case. […]


  6. […] New features in WordPress 2.0? A lot of people are still asking what the differences are between WordPress version 1.5.2 and version 2.0. I did mention that a lot of the differences are under the surface, and I mentioned the WYSIWYG editor and the new user permissions scheme. Rather than list the changes here, I’ll point you to those who have already written about it. One of the best articles is probably What’s New in WordPress 2.0? over on Owen Winkler’s site. There are also several articles over on Ryan’s site which detail some of the new changes. Christmas Lights One of the things that I only recently discovered myself is the fact that images uploaded to a post become “attachments” which become sub-pages themselves. In other words, each uploaded image becomes a WordPress page, with its own comments. This gives you the basic functionality of a photo gallery without the need for any external software. Click on the image in this post for an example. […]


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