The Semiologic Cache plugin for WordPress is a high performance cache for sites built using WP.
It requires PHP 5.0 to work; some features (the query cache) require as much as PHP 5.1. The niftier functionality is only available on servers with memcached installed. This is not available on shared hosts; but if you're on a VPS host, such as Hub.org, you can take full advantage of it.
Activate the Semiologic Cache plugin, and browse Settings / Cache to use it. It implements the following:
- A filesystem-based static cache of key pages, for ultimate caching when you experience massive amounts of requests on individual pages.
- The semi-static cache, which can optionally be handled by memcache (allowing sites who live on multiple servers to avoid lags related to the filesystem).
- A query-level cache for sites that use memcache; this significantly speeds things up for logged in users, provided they haven't authored private posts.
- A persistent object-level cache, again using memcache. This speeds things up for much about everyone, by avoiding round trips to the database when none are needed.
- A gzip-level cache at the apache level, for servers that support mod_deflate. This significantly reduces the size of the files sent to end-users whose browser support it.
This package is part of Semiologic Pro, and is access-restricted.
Bleeding Edge Zip
Frequently Asked Questions
The Semiologic forum is the best place to report issues.
- Further optimization of css compression code.
- Css script could be moved to footer area impacting site presentation.
- Fix bug in handling of external css files only starting with url of /example.com/file/..... (no http: or https:)
- Initial support for css compression. Seeing 10-25% file size improvements.
- Caches flushed on WP upgrade
- Code refactoring
- Silence 'Directory not empty' warning message in the cache-fs.php file
- Further tweaking to fix invalid operation warning message in the cache-fs.php file
- WP 3.9 compat
- Added ability to manually disable caching for a page.
- Pages that include the Semiologic Contact Form widget are no longer cached. Caching conflicted with spam prevention techniques and was resulting in occasional false positives.
- Fix invalid operation warning message in the cache-fs.php file
- Updated htaccess caching rules
- Some Static Cache rules written to htaccess even if cached was turn off.
- Fixed undefined variable in query_cache module
- WP 3.8 compat
- Fix Undefined variable: wpdb in /wp-content/plugins/sem-cache/query-cache.php on line 526 warning
- Updated htaccess caching rules
- www -> non-www or non-www -> www redirect rules added to htaccess is caching is turned on.
- WP 3.6 compat
- PHP 5.4 compat Important: Turn the cache off (Settings->Cache) then back on to force new server rules to be written
- Add Blackberry 10 User Agent detection
- Turn off auto enabling of cache
- Resolved unknown index warnings
- Fix: 3rd time the charm? wpdb::escape_by_ref() expected to be a reference message in query-cache.php
- Fix: wpdb::escape_by_ref() expected to be a reference message in query-cache.php
- Silence warning message attempting to delete non-existant file
- Fix misc. coding errors spotted by phpstorm
- Fix: Detection of mobile user agents that used mixed case failed
- Updated mobile agent detection Opera and Android Tablets
- Asset cache is now cleared when Scripts & Meta is updated, theme is switched or plugins are activated/deactivated
- Flush cache on Profile update due to Google+ Authorship
- Fix warning message deleting non-existent file. Seems to be PHP 5.3 issue
- Fix static caching as WP_CACHE was not being written to wp-config.php
- Add mod_expires and mod_mime sections.
- Added more mod_deflate filters
- Add cache control headers
- Added auto-enable logic and source code switch to enable
- Updated mobile User Agents
- WP 3.0.1 compat
- WP 3.0 compat
- Fix Apache 1.3 quirks
- Improve safe_mode and open_basedir handling
- Complete rewrite
- Add query cache, object cache, asset cache and gzip cache
- Improve handling of custom wp-content and plugin folders
- Don't super cache requests with a cookie or GET parameter