Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Memcache Configuration Options

Name	Default	Changeable	Changelog
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.
memcache.protocol	ascii	>PHP_INI_ALL	Supported since memcache 3.0.0
memcache.redundancy	1	>PHP_INI_ALL	Supported since memcache 3.0.0
memcache.session_redundancy	2	>PHP_INI_ALL	Supported since memcache 3.0.0
memcache.compress_threshold	20000	>PHP_INI_ALL	Supported since memcache 3.0.3
memcache.lock_timeout	15	>PHP_INI_ALL	Supported since memcache 3.0.4

Session Configuration Options Affecting Memcache Behavior

Name	Default	Changeable	Changelog
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

For further details and definitions of the PHP_INI_* modes, see the Where a configuration setting may be set.

Here's a short explanation of the configuration directives.

memcache.allow_failover bool

Whether to transparently failover to other servers on errors.

memcache.max_failover_attempts int

Defines how many servers to try when setting and getting data. Used only in conjunction with memcache.allow_failover.

memcache.chunk_size int

Data will be transferred in chunks of this size, setting the value lower requires more network writes. Try increasing this value to 32768 if noticing otherwise inexplicable slowdowns.

memcache.default_port string

The default TCP port number to use when connecting to the memcached server if no other port is specified.

memcache.hash_strategy string

Controls which strategy to use when mapping keys to servers. Set this value to consistent to enable consistent hashing which allows servers to be added or removed from the pool without causing keys to be remapped. Setting this value to standard results in the old strategy being used.

memcache.hash_function string

Controls which hash function to apply when mapping keys to servers, crc32 uses the standard CRC32 hash while fnv uses FNV-1a.

memcache.protocol string

memcache.redundancy int

memcache.session_redundancy int

memcache.compress_threshold int

memcache.lock_timeout int

session.save_handler string

Use memcache as a session handler by setting this value to memcache.

session.save_path string

Defines a comma separated of server urls to use for session storage, for example "tcp://host1:11211, tcp://host2:11211".

Each url may contain parameters which are applied to that server, they are the same as for the Memcache::addServer() method. For example "tcp://host1:11211?persistent=1&weight=1&timeout=1&retry_interval=15"