I am up to here in drupal documentation :
Start at least one instance of memcached on your server. Edit settings.php to make memcache the default cache class, for example: $conf['cache_backends'][] = 'sites/all/modules/contrib/memcache/memcache.inc'; $conf['cache_default_class'] = 'MemCacheDrupal'; $conf['memcache_key_prefix'] = 'something_unique';
Why do I need a memcache key prefix if have only one database? Anyway where and how do I set it?