The plugin implements object level persistent caching and can be used instead of the built in WordPress
Unlike WP Super Cache, Hyper Cache and other plugins, EM Object Cache does not cache the entire page; instead, it caches the data WordPress explicitly asks it to cache (using
wp_cache_xxx() API functions).
Although this means that the performance will be less than with, say, WP Super Cache, all your pages remain dynamic.
EM Object Cache won’t help you much if the plugins or theme you are using do not use WordPress Cache API.
This is by design, since the plugin tries to play nice. However, for most WordPress installations this will not be critical.
EM Object Cache significantly reduces the load from your database. Say, my blog’s home page without the plugin
executes 24 queries (0.02403 sec); with the plugin enabled, only 4 queries (0.00188 sec).
Unlike DB Cache/DB Cache Reloaded, the plugin will work in the Admin Panel and supports all plugins that use WordPress Cache API.
* if you want to use FileCache caching engine, chances are that the plugin will not work when PHP safe mode is enabled and web server is operated by a different user than owns the files.
- Please make sure that
wp-contentdirectory is writable by the web server: the plugin will need to delete
- Deactivate/uninstall the plugin in the ‘Plugins’ menu in WordPress.
- Please verify that
wp-content/object-cache.phpfile was removed.
- The plugin does not work with Custom Field Template plugin.
This is because Custom Field Template maintains its own cache for the post meta data which gets out of sync with WordPress cache. Please add
cft_post_metato the list of the non-persistent groups (EM Object Cache > Generic Options)
- After activation of FileCache engine, I see an error: “Warning: file_exists(): open_basedir restriction in effect. File(`filename`) is not within the allowed path(s)”. What to do?
A1: Try to get rid of
open_basedirform your php.ini/Apache config.
open_basediris considered a “broken” security measure anyway and only slows down file operations.
A2: If disabling
open_basediris not an option, set the
Cache locationunder the EM Object Cache > FileCache to the directory that satisfies the
Improving many blogs for years.
With recent APCu-deployments compatibility breaks on default settings this engine and requires
apcu-bc additions. But as the engine is optional this is no serious concern.
incredible speed up!
1. Original without plugin: 0,395 sec
2. With plugin: 5,458 sec
EMOC 2.1 (Jul 08, 2013)
- Changed all paths from
em-object-cachedue to WP requirements (“an underscore character is not valid in a path, therefore you can’t have em_object_cache as the plugin’s slug. Only alphanumeric characters and the dash are valid.”).
EMOC 2.0 (Jun 08, 2013)
- First public release of EM Object Cache
- Work around a weird bug when $_wp_using_ext_object_cache somehow resets to true (0a41da8)
- Major refactoring of SJOC codebase
- igbinary support (bbf61ad)
- Compatibility with WP 3.6
- Added guards to fix path disclosure vulnerability (d595b19)
WPFC 188.8.131.52 (Dec 16, 2010)
- Fixed stupid bug
WPFC 1.2.9 (Dec 15, 2010)
- Ability to disable caching when memory is low
SJOC 1.3 (Oct 31, 2010)
- Bug fix with Memcached engine registration
- Removed FileGroupCache
- Get rid of
SJOC 1.2 (Oct 14, 2010)
- Added Memcache/Memcached support
WPFC 184.108.40.206 (Apr 8, 2010)
- Suppress ‘stat failed’ warning for
WPFC 220.127.116.11 (Apr 7, 2010)
- Save options bug fix
WPFC 1.2.8 (Mar 27, 2010)
- Added Ukrainian translation (props Andrey K.)
- Fixed typos in readme.txt
WPFC 1.2.7 (Mar 12, 2010)
- Option to always use fresh data in the Admin Panel
- Added Belarussian translation (props Antsar)
SJOC 1.1 (Mar 25, 2010)
- Experimental WPMU support
SJOC 1.0 (Mar 8, 2010)
- Declared RC3 stable
WPFC 1.2.6 (Mar 6, 2010)
- Updated FAQ
- Added an experimental option to partially disable the cache in the Admin panel
WPFC 1.2.5 (Feb 15, 2010)
- Data to be cached are not passed by reference anymore to ensure there are no side effects
- Objects are cloned before caching to avoid any side effects
WPFC 1.2.4 (Feb 14, 2010)
- Fixed wrong directory name
WPFC 1.2.3 (Feb 12, 2010)
- readme.txt bug fix
WPFC 1.2.2 (Feb 12, 2010)
- Compatibility with WP 3.0
WPFC 1.2.1 (Jan 14, 2010)
- optimized the code, speeded up
FileCacheclass methods by moving all sanity checks to
- file lock on write
- less system calls are used
- compatibility with WordPress 2.6
- plugin won’t cause WSoD if the plugin is deleted but wp-content/object-cache.php file is not
SJOC 1.0rc3 (Jan 4, 2010)
$__sjfc_optionsis forcefully global variable
- admin_menu and admin_init hooks are set up only when is_admin() is true
- unset all internally used variables in object-cache.php
- added wp_cache_reset() support
- cache is not persistent when
$_SERVER['HTTP_HOST']is not set (CLI mode)
- moved sanity checks from BaseCache to wp_cache_add_global_groups() and wp_cache_add_non_persistent_groups()
- removed eAcceleratorGroupCache and xGroupCache
- FileCache: use
- Minor PHP code optimizations
SJOC 1.0rc2 (Jan 3, 2010)
- Renamed SjObjectCache to SJ Object Cache
- load_plugin_textdomain() is called only if is_admin() is true (translations are not used in user mode)
SJOC 1.0rc1 (Dec 20, 2009)
- Added eAcceleratorGroupCache
- Moved several checks from BaseCache to wp_cache_XXX() functions to speed up internally used functions
- Minor PHP code optimizations
- Better wp_cache_flush() implementation for APC, eAccelerator and XCache
WPFC 1.1 (Dec 19, 2009)
- Fixed serious floating bug in
SJOC 0.01 (Sep 22, 2009)
- The first version of SJ Object Cache (proof of concept). Supported engines: APC, XCache, eAccelerator, FileCache, FileGroupCache, Zend Disk Cache, Zend Shared Memory Cache, XGroupCache
WPFC 1.0 (Dec 2, 2008)
- Really do not remember
WPFC 0.2.1 (Jun 12, 2008)
- First public release