Questions about enabling the object cache using Memcached

trellis
1

Hello!

So, I decided that for funsies I would set up the next site using Memcached instead of Redis as the object cache provider.

The documentation leaves a lot to be desired though, or maybe (most likely?) this is a skill issue

So I’ve added this to the development/wordpress_sites.yml:

object_cache:
    enabled: true
    provider: memcached 
    database: 0

And I’ve installed the suggested plugin with
composer require wpackagist-plugin/memcached

Now to the part where I get confused.
The documentation says:

The plugin typically auto-activates when it detects Memcached is available.

Is this an actual thing? Can a plugin auto-activate?

More importantly, when I try to activate the plugin manually I get this error:

Cannot redeclare function wp_cache_add()

Now according to the plugin’s site this is because it requires a very manual installation process:

  1. Install memcached on at least one server. Note the connection info. The default is 127.0.0.1:11211.
  2. Install the PECL memcache extension
  3. Copy object-cache.php to wp-content
  4. Add the WP_CACHE_KEY_SALT constant to the wp-config.php:phpdefine( 'WP_CACHE_KEY_SALT', '...long random string...' );

So the question is, what’s the recommended way of using Memcached these days? Is the recommendation a blank “use Redis instead, stoopid!” or is the documentation linking to the wrong plugin or something?

All help, feedback or hate is welcome with open arms.