libmemcached Configuration

SYNOPSIS

#include <libmemcached-|libmemcached_version|/memcached.h>
Compile and link with -lmemcached
memcached_st *memcached(const char *string, size_t string_length)
Parameters:
  • string -- configuration string
  • string_length -- length of the configuration string without any terminating zero
Returns:

allocated and initialized memcached_st struct
memcached_return_t libmemcached_check_configuration(const char *option_string, size_t length, char *error_buffer, size_t error_buffer_size)
Parameters:
  • option_string -- configuration string
  • length -- length of the configuration string without any terminating zero
  • error_buffer -- buffer used to store any error message
  • error_buffer_size -- available size of the error_buffer
Returns:

memcached_return_t indicating success

DESCRIPTION

libmemcached implements a custom language for configuring and modifying servers. By passing in an option string you can generate a memcached_st object that you can use in your application directly.

General Options:

--SERVER=<servername>:<optional_port>/?<optional_weight>

Provide a servername to be used by the client.

Providing a weight will cause weighting to occur with all hosts with each server getting a default weight of 1.

--SOCKET="<filepath>/?<optional_weight>"

Provide a filepath to a UNIX socket file. Providing a weight will cause weighting to occur with all hosts with each server getting a default weight of 1.

--VERIFY-KEY

Verify that keys that are being used fit within the design of the protocol being used.

--REMOVE_FAILED_SERVERS

Enable the behavior MEMCACHED_BEHAVIOR_REMOVE_FAILED_SERVERS.

--BINARY-PROTOCOL

Force all connections to use the binary protocol.

--BUFFER-REQUESTS

Please see MEMCACHED_BEHAVIOR_BUFFER_REQUESTS.

--CONFIGURE-FILE=

Provide a configuration file to be used to load requests. Beware that by using a configuration file libmemcached will reset memcached_st based on information only contained in the file.

--CONNECT-TIMEOUT=

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT.

--DISTRIBUTION=

Set the distribution model used by the client. See memcached_behavior_set() for more details.

--HASH=

Set the hashing algorithm used for placing keys on servers.

--HASH-WITH-NAMESPACE

When enabled the prefix key will be added to the key when determining which server to store the data in.

--NOREPLY

Enable "no reply" for all calls that support this. It is highly recommended that you use this option with the binary protocol only.

--NUMBER-OF-REPLICAS=

Set the number of servers that keys will be replicated to.

--RANDOMIZE-REPLICA-READ

Select randomly the server within the replication pool to read from.

--SORT-HOSTS

When adding new servers always calculate their distribution based on sorted naming order.

--SUPPORT-CAS

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_SUPPORT_CAS

--USE-UDP

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_USE_UDP

--NAMESPACE=

A namespace is a container that provides context for keys, only other requests that know the namespace can access these values. This is accomplished by prepending the namespace value to all keys.

Memcached Pool Options:

--POOL-MIN

Initial size of pool.

--POOL-MAX

Maximize size of the pool.

I/O Options:

--TCP-NODELAY

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_TCP_NODELAY

--TCP-KEEPALIVE

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_TCP_KEEPALIVE

--RETRY-TIMEOUT=

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_RETRY_TIMEOUT

--SERVER-FAILURE-LIMIT=

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT

--SND-TIMEOUT=

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_SND_TIMEOUT

--SOCKET-RECV-SIZE=

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_SOCKET_RECV_SIZE

--SOCKET-SEND-SIZE=

See memcached_behavior_set() for MEMCACHED_BEHAVIOR_SOCKET_SEND_SIZE

--POLL-TIMEOUT=

Set the timeout used by poll(3).

--IO-BYTES-WATERMARK=
--IO-KEY-PREFETCH=
--IO-MSG-WATERMARK=
--TCP-KEEPIDLE
--RCV-TIMEOUT=

Other Options:

INCLUDE

Include a file in configuration. Unlike --CONFIGURE-FILE= this will not reset memcached_st.

RESET

Reset memcached_st and continue to process.

END

End configuration processing.

ERROR

End configuration processing and throw an error.

ENVIRONMENT

LIBMEMCACHED

RETURN VALUE

memcached() returns a pointer to the memcached_st that was created (or initialized). On an allocation failure, it returns NULL.

EXAMPLE

const char *config_string=
  "--SERVER=host10.example.com "
  "--SERVER=host11.example.com "
  "--SERVER=host10.example.com";
memcached_st *memc= memcached(config_string, strlen(config_string));
{
  // ...
}
memcached_free(memc);