php.ini文件末尾添加
extension=php_memcache.dll
[Memcache]
memcache.allow_failover = 1
memcache.max_failover_attempts=20
memcache.chunk_size =8192
memcache.default_port = 11211
然后在wamp\bin\php\php5.5.12\ext目录下添加和你php版本相同的php_memcache.dll文件
https://windows.php.net/downloads/pecl/releases/memcache/3.0.8/
原文：https://www.cnblogs.com/caidapeng/p/8889196.html