cache_users()WP 3.0.0

This is a pluggable function, and it can be replaced by a plugin. It means that this function is defined (works) only after all plugins are loaded (included), but before this moment this function has not defined. Therefore, you cannot call this and all functions depended on this function directly from a plugin code. They need to be called on plugins_loaded hook or later, for example on init hook.

Function replacement (override) — in a plugin you can create a function with the same name, then it replace this function.

No Hooks.


null. Nothing.


cache_users( $user_ids );
$user_ids(int[]) (required)
User ID numbers list


  • Global. wpdb. $wpdb WordPress database abstraction object.


Since 3.0.0 Introduced.

Code of cache_users() WP 6.0

function cache_users( $user_ids ) {
	global $wpdb;

	$clean = _get_non_cached_ids( $user_ids, 'users' );

	if ( empty( $clean ) ) {

	$list = implode( ',', $clean );

	$users = $wpdb->get_results( "SELECT * FROM $wpdb->users WHERE ID IN ($list)" );

	$ids = array();
	foreach ( $users as $user ) {
		update_user_caches( $user );
		$ids[] = $user->ID;
	update_meta_cache( 'user', $ids );