Conditionally avoid using the persistent storage backend with WP Object Cache

WordPress' non-persistent groups let you exclude groups of data from Redis or Memcached.

One common strategy¬†for improving WordPress’ performance is to use a service like Redis or Memcached as a persistent storage backend for the WP Object Cache. This lets you more easily cache the result of expensive data generation.

However, there are cases in which you don’t necessarily want¬†all of your object cache to end up in the persistent storage backend. For instance, if you have hundreds of cache calls on a pageload and each call takes 1 ms of network requests, you may want to prevent some of them from occurring. Enter: non-persistent groups.

First, make sure your calls to wp_cache_add( $key, $value, $group ); and wp_cache_set( $key, $value, $group ); include the third group argument. Then, to mark a group as non-persistent, use wp_cache_add_non_persistent_groups( $group_name );.