WordPress at a glance
function is not described

update_sitemeta_cache() WP 5.1.0

Updates metadata cache for list of site IDs.

Performs SQL query to retrieve all metadata for the sites matching $site_ids and stores them in the cache. Subsequent calls to get_site_meta() will not need to query the database.

No Hooks.

Return

Array/false. An array of metadata on success, false if there is nothing to update.

Usage

update_sitemeta_cache( $site_ids );
$site_ids(array) (required)
List of site IDs.

Changelog

Since 5.1.0 Introduced.

Code of update_sitemeta_cache() WP 5.5.1

<?php
function update_sitemeta_cache( $site_ids ) {
	// Ensure this filter is hooked in even if the function is called early.
	if ( ! has_filter( 'update_blog_metadata_cache', 'wp_check_site_meta_support_prefilter' ) ) {
		add_filter( 'update_blog_metadata_cache', 'wp_check_site_meta_support_prefilter' );
	}
	return update_meta_cache( 'blog', $site_ids );
}