is_site_meta_supported

WordPress Version: 5.1

/**
 * Determines whether site meta is enabled.
 *
 * This function checks whether the 'blogmeta' database table exists. The result is saved as
 * a setting for the main network, making it essentially a global setting. Subsequent requests
 * will refer to this setting instead of running the query.
 *
 * @since 5.1.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @return bool True if site meta is supported, false otherwise.
 */
function is_site_meta_supported()
{
    global $wpdb;
    if (!is_multisite()) {
        return false;
    }
    $network_id = get_main_network_id();
    $supported = get_network_option($network_id, 'site_meta_supported', false);
    if (false === $supported) {
        $supported = $wpdb->get_var("SHOW TABLES LIKE '{$wpdb->blogmeta}'") ? 1 : 0;
        update_network_option($network_id, 'site_meta_supported', $supported);
    }
    return (bool) $supported;
}