Title: [Plugin: APC Object Cache Backend] Cache does sometimes not refresh
Last modified: August 20, 2016

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# [Plugin: APC Object Cache Backend] Cache does sometimes not refresh

 *  Resolved [Bernhard Riedl](https://wordpress.org/support/users/neoxx/)
 * (@neoxx)
 * [14 years, 7 months ago](https://wordpress.org/support/topic/plugin-apc-object-cache-backend-cache-does-sometimes-not-refresh/)
 * Hi Mark,
 * Maybe you could shed some light on the following strange issue:
 * I have a bunch of WordPress installations (3.1 and 3.2) running on a Debian Squeeze
   with PHP 5.3.3-7, APC 3.1.3p1 and the development version of your APC plugin.
   If I update a setting (e.g. timezone) on one of my WordPress instances (single
   as well as multi-user network), the previous setting will not changed until I
   empty the APC user cache entries.
 * The default user_ttl is set to 0 and the apc-monitoring-tool apc.php shows no
   ttl, too:
 * for example:
    _wp:4299c432235aea4625c72c0c01d09d89:1:options:alloptions Ttl 0_
 * Any help is appreciated.
 * cheers,
    Berny
 * [http://wordpress.org/extend/plugins/apc/](http://wordpress.org/extend/plugins/apc/)

Viewing 4 replies - 1 through 4 (of 4 total)

 *  Thread Starter [Bernhard Riedl](https://wordpress.org/support/users/neoxx/)
 * (@neoxx)
 * [14 years, 7 months ago](https://wordpress.org/support/topic/plugin-apc-object-cache-backend-cache-does-sometimes-not-refresh/#post-2347681)
 * After some tests, it seems that for posts, pages, etc. the apc-cache-entry is
   updated on every change. Moreover, a call to `update_option()` works correctly
   as the following code delivers a fresh result if called for example in the init-
   hook.
 *     ```
       <?php
       $rand=rand();
   
       update_option('bogus', $rand);
       echo(get_option('bogus'));
       ?>
       ```
   
 * Though, I still have the issue in the WordPress Admin Menu and now it really 
   gets strange: The settings _TimeZone_, _Date Format_, _Time Format_, _Week Starts
   On_ and _Site language_ on [https://mydomain.com/wp-admin/options-general.php](https://mydomain.com/wp-admin/options-general.php)
   are written to the database on update but the cache is not updated. Other options
   on the same page like _Site Title_ or _Tagline_ are updated correctly in the 
   database and the cache.
 * I’ve also tested my plugins which use the WP 2.7 Settings-API and all of them
   update all options just fine in the database and the cache.
 * So I can rule out a bug in APC itself and start thinking that this issue is also
   not related with the APC Object Cache Backend plugin but rather caused by a bug
   in WordPress core.
 * Could anybody please test this behavior and provide me with some feedback.
 * greetz,
    Berny
 *  Plugin Author [Mark Jaquith](https://wordpress.org/support/users/markjaquith/)
 * (@markjaquith)
 * [14 years, 7 months ago](https://wordpress.org/support/topic/plugin-apc-object-cache-backend-cache-does-sometimes-not-refresh/#post-2347695)
 * Berny — Try the version of the APC backend in /trunk/
 * [http://svn.wp-plugins.org/apc/trunk/](http://svn.wp-plugins.org/apc/trunk/)
 * I just made some updates last night, and one of them was a weird bug where some
   sorts of numerical values would refuse to be stored in APC.
 * If the problem still persists, please narrow it down the smallest code snippet
   that reproduces the problem so I can look into it!
 *  Thread Starter [Bernhard Riedl](https://wordpress.org/support/users/neoxx/)
 * (@neoxx)
 * [14 years, 7 months ago](https://wordpress.org/support/topic/plugin-apc-object-cache-backend-cache-does-sometimes-not-refresh/#post-2347696)
 * Hi Mark,
 * Thanks for your feedback and the update. – I’ve installed 2.0.2b on our staging-
   server.
 * According to the cache-entries _alloptions_ is NULL now. – Thus, for example,
   changing the timezone-setting – as described before – works, though without any
   caching.
 * fyi: As you’ve pumped the minimum-requirement, you should probably also adopt
   the error-message ‘The APC object cache backend requires PHP 5.2 or higher’ to
   5.2.4.
 * Today I had the chance to test a similar setup on a windows server with your 
   plugin 2.0.2 and APC 3.1.6. – It seems that there all cache-entries get updated
   just fine.
 * I thought I can rule the APC cache itself out, but maybe after all it’s a bug
   in APC. – The behavior is confusing and errors are hard to reproduce…
 * So first of all, I will request an update of APC on our Debian staging-server
   and get back to you with further results.
 * Greetz,
    Berny
 *  Thread Starter [Bernhard Riedl](https://wordpress.org/support/users/neoxx/)
 * (@neoxx)
 * [14 years, 6 months ago](https://wordpress.org/support/topic/plugin-apc-object-cache-backend-cache-does-sometimes-not-refresh/#post-2347739)
 * Hi Mark,
 * Good news. 🙂 After compiling and updating APC to version 3.1.9 and a running
   a few tests during the last week everything works fine with your plugin 2.0.2(
   stable).
 * I can still only speculate because the results are hard to reproduce, but it 
   seems that either APC 3.1.3p1 itself or the combination of Debian Squeeze with
   PHP 5.3.3-7 and APC 3.1.3p1 caused this issue.
 * Greetz,
    Berny

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘[Plugin: APC Object Cache Backend] Cache does sometimes not refresh’ 
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 * 4 replies
 * 2 participants
 * Last reply from: [Bernhard Riedl](https://wordpress.org/support/users/neoxx/)
 * Last activity: [14 years, 6 months ago](https://wordpress.org/support/topic/plugin-apc-object-cache-backend-cache-does-sometimes-not-refresh/#post-2347739)
 * Status: resolved