Been having a bit of a problem with my site regarding our caching method and my php code not refreshing or flushing.
To start, my site is a WordPress site on a dedicated Nginx webserver. I used W3 Total Cache for the initial caching setup. Everything was set up to cache through Memcached.
(I should note, my website is somewhat of a ‘guest’ on this server, which is bit of a semi-community donation semi-sponsored server that runs some other things. The admins are skilled but also volunteers. I have their full support for fixing things, but they don’t have time to troubleshoot my very odd issue (especially because I asked for caching to get turned on for the site myself). If we had some hints on what to go on it would make things easier for us than taking shots in the dark 😉 So any suggestions are welcomed.)
At some point we noticed that changes to php pages and WordPress & Plugin updates were not working at all, while the code on the server reflected updates, the pages still processed through the older php code.
This presented a couple unique issues. W3 Total Cache stores it settings in php files. Other php files, when deleted, stop working, but when they are restored to the server, memcached still insists on using its ultra-old memcached copy. The W3 Total Cache settings, whether i removed or altered the settings php files, would NOT stop running everything through cached memcached data.
The server admin attempt rebooting memcached and then flushing it. Neither of those seemed to have any effect. All the other basic settings seem to be set-up correctly.
We can, of course, still add new plugins, all the data that comes from the database works just fine.
At least one other site on the server that is not wordpress also uses memcached with no issues.
Any help is appreciated, should be able to provide further information if it is needed.
Do you have apc.stat = 0 in your settings? Does restarting php engine help?