What is the most efficient way to search users by their display name?

Question

Initially I thought I'd use get_users() but it turned out it doesn't support the display_name field. Then I've read about using WP_User_Query, but when I do it always exhausts the allowed memory size of 134217728 bytes. When I remove the memory limit this part of the page doesn't even try to load. Now I'm thinking about running a function that adds everyone's display_name to their user meta so I can use get_users() again. Is that a good idea?

My objective is to make the search also sort by relevance and I plan to do it by using explode(' ', $search_query) then call get_users() for each element in the array, then combine and sort the results by occurance like it's shown here: https://stackoverflow.com/questions/2176626/php-get-element-with-5-highest-occurrence-in-an-array and I'm not sure if that's going to be memory efficient.

Thanks for reading.

Answer 1

I think you should use the default class for this job - WP_User_Query. The query have a lot of possibilities, also get the display name. WP_User_Query is a class that allows querying WordPress database tables _users and _usermeta.

Also it is helpful when you use a cache for the values. Also here I prefer the WordPress defaults WP_Cache (Non-Persistent Cache) or transient API (Database-Driven Temporarily Persistent Cache).

The example below will demonstrate this with WP_Cache, you can also doing this with transients. The code will not work, is only write by scratch to illustrate.

function wpse_get_user_data( $args ) {


    if ( ! $user_query = wp_cache_get( $args->ID, 'your_key' ) ) {
        $user_query = array();
        $user_query = new WP_User_Query( $args );

        wp_cache_add( $args-ID, $user_query, 'your_key' );
    }

    return $user_query;
}

Answer 2

If you push a "search" through WP_User_query you will search both the user_login fields and the user_nicename fields. That produces a de facto inefficient OR query. You can reduce that by using a filter to force the search to only the user_nicename field.

add_filter('user_search_columns','nicename_only_wpse_188846');

function nicename_only_wpse_188846($search_columns) {
  return array('user_nicename');
}

$args = array(
  'search' => 'abce',
);

// The Query
$user_query = new WP_User_Query( $args );
var_dump($user_query);

Combine that with caching and you might have a shot.

That said, 134217728 bytes is pretty slim if you have a lot of users and traffic. You may just need a server upgrade.