MySQL Memcache_engine的安装与使用 Memcache_engine是一个MySQL 5.1数据库的存储引擎，它能够让用户通过标准的SQL语句（SELECT/UPDATE/INSERTE/DELETE）访问Memcached（还支持新浪的Memcachedb、dbcached）中存放的数据。
memcachedb英文版使用手册 ”Memcachedb is a distributed key-value storage system design for persistent.” A complete memcached, but *NOT* a cache solution Memcached is good enough for cache. *NO* expiration For memcache protocol compatible, still reserved, bu
redis是一个key-value存储系统.和Memcached类似，它支持存储的value类型相对更多，包括string(字符串)、list(链表)、set(集合)、zset(sorted set --有序集合)和hashs（哈希类型）.这些数据类型都支持push/pop、add/remove及取交集并集和差集及更丰富的操作，而且这些操作都是原子性的.在此基础上，redis支持各种不同方式的排序.与memcached一样，为了保证效率，数据都是缓存在内存中.区别的是redis会周期性的把更新
”Memcachedb is a distributed key-value storage system designed for persistent.” A complete memcached, but *NOT* a cache solution Memcached is good enough for cache. *NO* expiration For memcache protocol compatible, still reserved, but we do nothing.
memcacheDB一起使用的BerkeleyDB 4.6.21， The industry-leading open source, embeddable database engine that provides developers with fast, reliable, local persistence with zero administration.
