The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| memcached.sess_locking | On | PHP_INI_ALL | Available as of memcached 0.1.0. |
| memcached.sess_consistent_hash | On | PHP_INI_ALL | Available as of memcached 2.1.0. Default value is On as of memcached 3.0.0. |
| memcached.sess_binary | Off | PHP_INI_ALL | Available as of memcached 2.0.0. Replaced by memcached.sess_binary_protocol as of memcached 3.0.0. |
| memcached.sess_lock_wait | 150000 | PHP_INI_ALL | Available as of memcached 0.1.0. Removed as of memcached 3.0.0. |
| memcached.sess_prefix | memc.sess.key. | PHP_INI_ALL | Available as of memcached 0.1.0. |
| memcached.sess_number_of_replicas | 0 | PHP_INI_ALL | Available as of memcached 2.1.0. |
| memcached.sess_randomize_replica_read | Off | PHP_INI_ALL | Available as of memcached 2.1.0. |
| memcached.sess_remove_failed | On | PHP_INI_ALL | Available as of memcached 2.1.0. Replaced by memcached.sess_remove_failed_servers as of memcached 3.0.0. |
| memcached.compression_type | fastlz | PHP_INI_ALL | Available as of memcached 0.1.0. |
| memcached.compression_factor | 1.3 | PHP_INI_ALL | Available as of memcached 0.1.0. |
| memcached.compression_threshold | 2000 | PHP_INI_ALL | Available as of memcached 0.1.0. |
| memcached.serializer | igbinary | PHP_INI_ALL | Available as of memcached 0.1.0. |
| memcached.use_sasl | Off | PHP_INI_ALL | Available as of memcached 2.2.0. Removed as of memcached 3.0.0. |
| memcached.default_binary_protocol | Off | PHP_INI_ALL | Available as of memcached 3.0.0. |
| memcached.default_connect_timeout | 0 | PHP_INI_ALL | Available as of memcached 3.0.0. |
| memcached.default_consistent_hash | Off | PHP_INI_ALL | Available as of memcached 3.0.0. |
| memcached.sess_binary_protocol | On | PHP_INI_ALL | Available as of memcached 3.0.0. Replace memcached.sess_binary. |
| memcached.sess_connect_timeout | 1000 | PHP_INI_ALL | Available as of memcached 2.2.0. |
| memcached.sess_consistent_hash_type | ketama | PHP_INI_ALL | Available as of memcached 3.1.0. |
| memcached.sess_lock_expire | 0 | PHP_INI_ALL | Available as of memcached 2.2.0. |
| memcached.sess_lock_retries | 5 | PHP_INI_ALL | Available as of memcached 3.0.0. |
| memcached.sess_lock_wait_max | 150 | PHP_INI_ALL | Available as of memcached 3.0.0. Default value 150 as of memcached 3.1.0 (previously 2000). |
| memcached.sess_lock_wait_min | 150 | PHP_INI_ALL | Available as of memcached 3.0.0. Default value 150 as of memcached 3.1.0 (previously 1000). |
| memcached.sess_persistent | Off | PHP_INI_ALL | Available as of memcached 3.0.0. |
| memcached.sess_remove_failed_servers | Off | PHP_INI_ALL | Available as of memcached 3.0.0. Replace memcached.sess_remove_failed. |
| memcached.sess_server_failure_limit | 0 | PHP_INI_ALL | Available as of memcached 3.0.0. |
| memcached.sess_sasl_password | null | PHP_INI_ALL | Available as of memcached 2.2.0. |
| memcached.sess_sasl_username | null | PHP_INI_ALL | Available as of memcached 2.2.0. |
| memcached.store_retry_count | 2 | PHP_INI_ALL | Available as of memcached 2.2.0. |
Here's a short explanation of the configuration directives.
memcached.sess_locking
bool
Use session locking. Valid values: On, Off, the default is On.
memcached.sess_consistent_hash
bool
If set to On, consistent hashing (libketama) is used for session handling. When consistent hashing is used, one can add or remove cache node(s) without messing up too much with existing keys. Default is On.
memcached.sess_binary
bool
Use memcached session binary mode. Libmemcached replicas only work if binary mode is enabled. The default is Off.
memcached.sess_lock_wait
int
Session spin lock retry wait time in microseconds. Be careful when setting this value. Valid values are integers, where 0 is interpreted as the default value. Negative values result in a reduces locking to a try lock. The default is 150000.
memcached.sess_prefix
string
Memcached session key prefix. Valid values are strings less than 219 bytes long. The default value is "memc.sess.key."
memcached.sess_number_of_replicas
int
Write data to a number of additional memcached servers. This is "poor man's HA" as libmemcached calls it. If this value is positive and sess_remove_failed_servers is enabled when a memcached server fails the session will continue to be available from a replica. However, if the failed memcache server becomes available again it will read the session from there which could have old data or no data at all. Default is 0.
memcached.sess_randomize_replica_read
bool
Memcached session replica read randomize.
memcached.sess_remove_failed
int
Allow failed memcached server to automatically be removed.
memcached.compression_type
string
Set the compression type, valid values are: fastlz, zlib. The default is fastlz.
memcached.compression_factor
float
Compression factor. Store compressed value only if the compression
factor (saving) exceeds the set limit. Store compressed if:
plain_len > comp_len * factor. The default value
is 1.3 (23% space saving).
memcached.compression_threshold
int
The compression threshold. Do not compress serialized values below this threshold. The default is 2000 bytes.
memcached.serializer
string
Set the default serializer for new memcached objects. Valid values are: php, igbinary, json, json_array, msgpack.
Standard php JSON encoding. This serializer is fast and compact but only works on UTF-8 encoded data and does not fully implement serializing. See the JSON extension. Available as of memcached 0.2.0.
As json, but decodes into arrays. Available as of memcached 2.0.0.
The standard PHP serializer.
A binary serializer. Available as of memcached 0.1.4.
A cross-language binary serializer. Available as of memcached 2.2.0.
The default is igbinary if available, then msgpack if available, then php otherwise.
memcached.use_sasl
bool
Use SASL authentication for connections. Valid values: On, Off. The default is Off.
memcached.default_binary_protocol
bool
Sets the default memcached protocol for new connections. (To configure the memcached protocol for connections used by sessions, use memcached.sess_binary_protocol instead) If set to On, the memcached binary protocol is used by default. If set to Off, the memcached text protocol is used. Default is Off
memcached.default_connect_timeout
int
Sets the default memcached connection timeout for new connections. (To configure the memcached connection timeout for sessions, use memcached.sess_connect_timeout instead) In non-blocking mode this changes the value of the timeout. during socket connection in milliseconds. Specifying -1 means an infinite timeout. Specifying 0 means using the memcached library's default connection timeout. Default is 0.
memcached.default_consistent_hash
bool
Sets the default for consistent hashing for new connections. (To configure consistent hashing for session connections, use memcached.sess_consistent_hash instead) If set to On, consistent hashing (libketama) is used for session handling. When consistent hashing is used, one can add or remove cache node(s) without messing up too much with existing keys default is Off
memcached.sess_binary_protocol
bool
Use the memcached binary protocol for memcached sessions (Instead of the text protocol) libmemcached replicas work only if binary mode is enabled. However, certain proxies (such as twemproxy) will work only if the binary protocol is disabled. In older versions of php-memcached, this setting was Off and was called memcached.sess_binary. Default is On with libmemcached 1.0.18 or newer. Default is Off with older version.
memcached.sess_connect_timeout
int
memcached connect timeout value In non-blocking mode this changes the value of the timeout during socket connection in milliseconds. Specifying -1 means an infinite timeout.
memcached.sess_consistent_hash_type
string
Memcached session consistent hash type. If set to 'ketama', consistent hashing (libketama) is used for session handling (default for php-memcached 3.x) if set to 'ketama_weighted', weighted consistent hashing (libketama) is used for session handling (default for php-memcached 2.x). Default is "ketama".
memcached.sess_lock_expire
int
The time, in seconds, before a lock should release itself. Setting to 0 results in the default behaviour, which is to use PHP's max_execution_time. Default is 0.
memcached.sess_lock_retries
int
The number of times to retry locking the session lock, not including the first attempt. Default is 5.
memcached.sess_lock_wait_max
int
The maximum time, in milliseconds, to wait between session lock attempts. The default is 150.
memcached.sess_lock_wait_min
int
The minimum time, in milliseconds, to wait between session lock attempts. This value is double on each lock retry until memcached.sess_lock_wait_max is reached, after which any further retries will take sess_lock_wait_max seconds. The default is 150.
memcached.sess_persistent
bool
Whether or not to re-use the memcached connections corresponding to the value(s) of session.save_path after the execution of the script ends. Don't use this if certain settings (e.g. SASL settings, sess_binary_protocol) would be overridden between requests. Default is Off.
memcached.sess_remove_failed_servers
bool
Allow failed memcached server to automatically be removed. Default is Off. (In previous versions, this setting was called memcached.sess_remove_failed)
memcached.sess_server_failure_limit
int
Set this value to enable the server be removed after configured number of continuous times connection failure. Default is 0.
memcached.sess_sasl_password
string
Session SASL password Both username and password need to be set for SASL to be enabled
memcached.sess_sasl_username
string
Session SASL username Both username and password need to be set for SASL to be enabled
memcached.store_retry_count
int
The amount of retries for failed store commands. This mechanism allows transparent fail-over to secondary servers when set/increment/decrement/setMulti operations fail on the desired server in a multi-server environment. the default is 2