Fatal error: Cannot redeclare wp_cache_add()

  • Resolved Razva

    (@razva)


    1 year, 11 months ago

    Hey,

    I’m getting this when trying to install your plugin:

    Fatal error: Cannot redeclare wp_cache_add() (previously declared in /home/plantemania/public_html/wp-includes/cache.php:41) in /home/plantemania/public_html/wp-content/plugins/object-cache.php on line 19

    Please note that I have manually uploaded object-cache.php to wp-content as recommended in the installation instructions.

    I’ve also added define( 'WP_CACHE_KEY_SALT', 'plantemania' ); in wp-config.php.

    Yes, the PHP module is installed and the service is running:

    plantemania@server:~$ php -m | grep memcache
memcached

plantemania@server:~$ systemctl status memcached
● memcached.service - memcached daemon
     Loaded: loaded (/lib/systemd/system/memcached.service; enabled; vendor preset: enabled)
     Active: active (running) since Fri 2022-12-16 08:58:34 EET; 32min ago
       Docs: man:memcached(1)
   Main PID: 1473014 (memcached)
      Tasks: 10 (limit: 4694)
     Memory: 29.6M
        CPU: 1.599s
     CGroup: /system.slice/memcached.service
             └─1473014 /usr/bin/memcached -m 64 -p 11211 -u memcache -l 127.0.0.1 -P /var/run/memcached/memcached.pid
plantemania@server:~$

    Any way to fix this? Thank you

    • This topic was modified 1 year, 11 months ago by Razva.
Viewing 5 replies - 1 through 5 (of 5 total)
  • Plugin Contributor Andrija Vu?ini?

    (@aidvu)

    Hey,

    plantemania@server:~$ php -m | grep memcache
    memcached

    So this isn’t the correct extension. It should return memcache not memcacheD.

    As for the fatal:

    Fatal error: Cannot redeclare wp_cache_add() (previously declared in /home/plantemania/public_html/wp-includes/cache.php:41) in /home/plantemania/public_html/wp-content/plugins/object-cache.php on line 19

    Did you by chance also install the plugin? If yes, uninstall and just copy object-cache.php to wp-content. No idea what the wp-content/plugins/object-cache.php file is (notice the /plugins).

    Thread Starter Razva

    (@razva)

    Hey,

    I appreciate the fast reply.

    As instructed I moved object-cache.php to from wp-content/plugins to wp-content. Here it is:

    $ ls ~/public_html/wp-content/
index.php  languages  object-cache.php  plugins  smush-webp  themes  upgrade  uploads

    Here’s the content’s of the plugins folder:

    $ ls ~/public_html/wp-content/plugins/
contact-form-7  google-site-kit  js_composer  meta-box            meta-box-tabs       redux-framework  sumodiscounts  wordpress-seo
envato-market   index.php        mailpoet     meta-box-show-hide  nt-agro-shortcodes  revslider        woocommerce    wp-smushit

    The current result is wp-admin throwing There has been a critical error on this website.

    I have uploaded a simple PHP script to test if memcache is working and it’s fully functional (on the same page you can find a phpinfo that confirms that memcache 3.2.0 is installed and fully functional).

    Any hints on this?

    Thank you!

    Later edit: I can confirm that both W3 and LiteSpeedCache plugins can connect to the memcache server and enable the Object Cache function.

    • This reply was modified 1 year, 11 months ago by Razva.
    • This reply was modified 1 year, 11 months ago by Razva.
    Plugin Contributor Andrija Vu?ini?

    (@aidvu)

    The current result is?wp-admin?throwing?There has been a critical error on this website.

    What does the PHP error log show for this now that you’ve moved the file?

    I have uploaded a?simple PHP script?to test if?memcache?is working and?it’s fully functional?(on the same page you can find a?phpinfo?that confirms that?memcache 3.2.0?is installed and fully functional).

    This is what I’ve been trying to tell you. ??

    There are two PECL extensions for memcached backend:

    Hope that helps.

    Thread Starter Razva

    (@razva)

    Oh, ok, sorry for my stupidity! I’ve successfully installed memcache.

    For posterity, doing apt install phpX-memcached does not equal with apt install phpX-memcache.

    The Critical error is not being displayed after installing the correct PECL extension.

    Thank you for your patience and support!

    Plugin Contributor Andrija Vu?ini?

    (@aidvu)

    Oh, ok, sorry for my stupidity! I’ve successfully installed memcache.

    Don’t worry. ?? Glad it works now!

    Thank you for your patience and support!

    <3

Viewing 5 replies - 1 through 5 (of 5 total)
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