The RA environment does not include a memcache service. As a result, you may encounter unexpected site behaviors or drush may return errors similar to:
WD memcache: Failed to connect to memcache server: 127.0.0.1:11211 [error]
This is usually the result of a memcache statement in your settings.php that is not properly enclosed in the suggested if statement (see: Using Memcached). For example, if your memcached statement looks like:
# Drupal 7
$conf['memcache_extension'] = 'Memcached';
# Drupal 8
$settings['memcache']['extension'] = 'Memcached';
It should be updated to look like the following instead:
# Drupal 7
if (isset($conf['memcache_servers'])) {
$conf['memcache_extension'] = 'Memcached';
}
# Drupal 8
if (isset($settings['memcache']['servers'])) {
$settings['memcache']['extension'] = 'Memcached';
}