PHP手册 - 运行时配置

运行时配置

这些函数的行为受 php.ini 中的设置影响。

**Memcache配置选项**
名字	默认	可修改范围	更新日志
memcache.allow_failover	"1"	PHP_INI_ALL	Available since memcache 2.0.2.
memcache.max_failover_attempts	"20"	PHP_INI_ALL	Available since memcache 2.1.0.
memcache.chunk_size	"8192"	PHP_INI_ALL	Available since memcache 2.0.2.
memcache.default_port	"11211"	PHP_INI_ALL	Available since memcache 2.0.2.
memcache.hash_strategy	"standard"	PHP_INI_ALL	Available since memcache 2.2.0.
memcache.hash_function	"crc32"	PHP_INI_ALL	Available since memcache 2.2.0.
session.save_handler	"files"	PHP_INI_ALL	Supported since memcache 2.1.2
session.save_path	""	PHP_INI_ALL	Supported since memcache 2.1.2

有关 PHP_INI_* 样式的更多详情与定义，见 Where a configuration setting may be set。

这是配置指令的简短说明。

memcache.allow_failover boolean

是否在发生错误时（对用户）透明的转移到其他服务器。

memcache.max_failover_attempts integer

定义在写入和获取数据时最多尝试的服务器次数（即：故障转移最大尝试数），仅和 memcache.allow_failover结合使用。

memcache.chunk_size integer

数据传输块大小，这个值越小网络I/O次数越多，如果发现莫名的速度降低，可以尝试将此值调至32768。

memcache.default_port string

在尝试连接memcache的时候如果没有单独指定端口默认使用的TCP端口号。

memcache.hash_strategy string

控制key到服务器的映射（分布式）策略。值 consistent允许服务器增减而不会（大量）导致健的重新映射（译注：参见http://tech.idv2.com/2008/07/24/memcached-004/），设置为 standard则使用余数方式进行key的映射。

memcache.hash_function string

控制在key-server映射时使用哪个hash函数crc32 标明使用标准CRC32进行hash，fnv则说明使用FNV-1a。

session.save_handler string

当值为memcache时标记使用memcache作为session处理器。

session.save_path string

定义一个逗号分割的用于session存储的服务器url列表，例如： "tcp://host1:11211, tcp://host2:11211".

每个url可以包含参数，这些参数于方法Memcache::addServer()的参数相同。比如： "tcp://host1:11211?persistent=1&weight=1&timeout=1&retry_interval=15"

PHP手册 - N: 运行时配置

用户评论:

info at phpgangsta dot de (14-Jan-2011 04:34)

Since 3.0.0 there are new defaults: memcache.hash_strategy = consistent memcache.chunk_size = 32768

kross at escapistmag dot com (22-Mar-2010 05:06)

There's a currently undocumented variable that is now available (you can see it in php_info()) for session handling: memcache.session_redundancy The default seems to be "2", and it is supposed to influence how many copies of a particular session object that Memcache will store for failover purposes (so with a redundancy of 2, it will store a session on 2 different shards). This will add slight overhead with extra writes, but overall seems worth it for purposes of failover.

ruben [AT] ruben dot cn (23-Oct-2008 02:05)

Please note that when you specify more than one memcached server, you don't get the session data copied to every memcached server. Info is only copied to the first one. If the 1st server is down, it goes for the second (but the second will lack the info stored into the 1st one)