Provided by: libmemcached-libmemcached-perl_1.001801+dfsg-4build3_amd64 bug

NAME

       memcached_behavior_get, memcached_behavior_set - Manipulate behavior

LIBRARY

       C Client Library for memcached (libmemcached, -lmemcached)

SYNOPSIS

         #include <memcached.h>

         uint64_t
           memcached_behavior_get (memcached_st *ptr,
                                   memcached_behavior flag);

         memcached_return_t
           memcached_behavior_set (memcached_st *ptr,
                                   memcached_behavior flag,
                                   uint64_t data);

DESCRIPTION

       libmemcached(3) behavior can be modified by use memcached_behavior_set().  Default behavior is the
       library strives to be quick and accurate. Some behavior, while being faster, can also result in not
       entirely accurate behavior (for instance, memcached_set() will always respond with "MEMCACHED_SUCCESS").

       memcached_behavior_get() takes a behavior flag and returns whether or not that behavior is currently
       enabled in the client.

       memcached_behavior_set() changes the value of a particular option of the client. It takes both a flag
       (listed below) and a value. For simple on or off options you just need to pass in a value of 1. Calls to
       memcached_behavior_set() will flush and reset all connections.

       MEMCACHED_BEHAVIOR_USE_UDP
           Causes libmemcached(3) to use the UDP transport when communicating with a memcached server. Not all
           I/O operations are supported when this behavior is enababled. The following operations will return
           "MEMCACHED_NOT_SUPPORTED" when executed with the MEMCACHED_BEHAVIOR_USE_UDP enabled:
           memcached_version(), memcached_stat(), memcached_get(), memcached_get_by_key(), memcached_mget(),
           memcached_mget_by_key(), memcached_fetch(), memcached_fetch_result(), memcached_value_fetch().

           All other operations are supported but are executed in a 'fire-and-forget' mode, in which once the
           client has executed the operation, no attempt will be made to ensure the operation has been received
           and acted on by the server.

           libmemcached(3) does not allow TCP and UDP servers to be shared within the same libmemached(3) client
           'instance'. An attempt to add a TCP server when this behavior is enabled will result in a
           "MEMCACHED_INVALID_HOST_PROTOCOL", as will attempting to add a UDP server when this behavior has not
           been enabled.

       MEMCACHED_BEHAVIOR_NO_BLOCK
           Causes libmemcached(3) to use asychronous IO. This is the fastest transport available for storage
           functions.

       MEMCACHED_BEHAVIOR_SND_TIMEOUT
           This sets the microsecond behavior of the socket against the SO_SNDTIMEO flag.  In cases where you
           cannot use non-blocking IO this will allow you to still have timeouts on the sending of data.

       MEMCACHED_BEHAVIOR_RCV_TIMEOUT
           This sets the microsecond behavior of the socket against the SO_RCVTIMEO flag.  In cases where you
           cannot use non-blocking IO this will allow you to still have timeouts on the reading of data.

       MEMCACHED_BEHAVIOR_TCP_NODELAY
           Turns on the no-delay feature for connecting sockets (may be faster in some environments).

       MEMCACHED_BEHAVIOR_HASH
           Makes the default hashing algorithm for keys use MD5. The value can be set to either
           MEMCACHED_HASH_DEFAULT, MEMCACHED_HASH_MD5, MEMCACHED_HASH_CRC, MEMCACHED_HASH_FNV1_64,
           MEMCACHED_HASH_FNV1A_64, MEMCACHED_HASH_FNV1_32, MEMCACHED_HASH_FNV1A_32, MEMCACHED_HASH_JENKINS,
           MEMCACHED_HASH_HSIEH, and MEMCACHED_HASH_MURMUR.  Each hash has it's advantages and it's weaknesses.
           If you don't know or don't care, just go with the default.  Support for MEMCACHED_HASH_HSIEH is a
           compile time option that is disabled by default. To enable support for this hashing algorithm,
           configure and build libmemcached with the --enable-hash_hsieh.

       MEMCACHED_BEHAVIOR_DISTRIBUTION
           Using this you can enable different means of distributing values to servers.  The default method is
           MEMCACHED_DISTRIBUTION_MODULA. You can enable consistent hashing by setting
           MEMCACHED_DISTRIBUTION_CONSISTENT.  Consistent hashing delivers better distribution and allows
           servers to be added to the cluster with minimal cache losses. Currently
           MEMCACHED_DISTRIBUTION_CONSISTENT is an alias for the value MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA.

       MEMCACHED_BEHAVIOR_CACHE_LOOKUPS
           Memcached can cache named lookups so that DNS lookups are made only once.

       MEMCACHED_BEHAVIOR_SUPPORT_CAS
           Support CAS operations (this is not enabled by default at this point in the server since it imposes a
           slight performance penalty).

       MEMCACHED_BEHAVIOR_KETAMA
           Sets the default distribution to MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA and the hash to
           MEMCACHED_HASH_MD5.

       MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED
           Sets the default distribution to MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA with the weighted support.
           and the hash to MEMCACHED_HASH_MD5.

       MEMCACHED_BEHAVIOR_KETAMA_HASH
           Sets the hashing algorithm for host mapping on continuum. The value can be set to either
           MEMCACHED_HASH_DEFAULT, MEMCACHED_HASH_MD5, MEMCACHED_HASH_CRC, MEMCACHED_HASH_FNV1_64,
           MEMCACHED_HASH_FNV1A_64, MEMCACHED_HASH_FNV1_32, and MEMCACHED_HASH_FNV1A_32.

       MEMCACHED_BEHAVIOR_KETAMA_COMPAT
           Sets the compatibility mode. The value can be set to either MEMCACHED_KETAMA_COMPAT_LIBMEMCACHED
           (this is the default) or MEMCACHED_KETAMA_COMPAT_SPY to be compatible with the SPY Memcached client
           for Java.

       MEMCACHED_BEHAVIOR_POLL_TIMEOUT
           Modify the timeout value that is used by poll(). The default value is -1. An signed int pointer must
           be passed to memcached_behavior_set() to change this value. For memcached_behavior_get() a signed int
           value will be cast and returned as the unsigned long long.

       MEMCACHED_BEHAVIOR_USER_DATA
           This allows you to store a pointer to a specifc piece of data. This can be retrieved from inside of
           memcached_fetch_execute(). Cloning a memcached_st

           will copy the pointer to the clone. This was deprecated in 0.14 in favor of
           memcached_callback_set(3). This will be removed in 0.15.

       MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
           Enabling buffered IO causes commands to "buffer" instead of being sent. Any action that gets data
           causes this buffer to be be sent to the remote connection. Quiting the connection or closing down the
           connection will also cause the buffered data to be pushed to the remote connection.

       MEMCACHED_BEHAVIOR_VERIFY_KEY
           Enabling this will cause libmemcached(3) to test all keys to verify that they are valid keys.

       MEMCACHED_BEHAVIOR_SORT_HOSTS
           Enabling this will cause hosts that are added to be placed in the host list in sorted order. This
           will defeat consisten hashing.

       MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT
           In non-blocking mode this changes the value of the timeout during socket connection.

       MEMCACHED_BEHAVIOR_BINARY_PROTOCOL
           Enable the use of the binary protocol. Please note that you cannot toggle this flag on an open
           connection.

       MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT
           Set this value to enable the server be removed after continuous
           MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT times connection failure.

       MEMCACHED_BEHAVIOR_IO_MSG_WATERMARK
           Set this value to tune the number of messages that may be sent before libmemcached should start to
           automatically drain the input queue. Setting this value to high, may cause libmemcached to deadlock
           (trying to send data, but the send will block because the input buffer in the kernel is full).

       MEMCACHED_BEHAVIOR_IO_BYTES_WATERMARK
           Set this value to tune the number of bytes that may be sent before libmemcached should start to
           automatically drain the input queue (need at least 10 IO requests sent without reading the input
           buffer). Setting this value to high, may cause libmemcached to deadlock (trying to send data, but the
           send will block because the input buffer in the kernel is full).

       MEMCACHED_BEHAVIOR_IO_KEY_PREFETCH
           The binary protocol works a bit different than the textual protocol in that a multiget is implemented
           as a pipe of single get-operations which are sent to the server in a chunk. If you are using large
           multigets from your application, you may improve the latency of the gets by setting this value so you
           send out the first chunk of requests when you hit the specified limit.  It allows the servers to
           start processing the requests to send the data back while the rest of the requests are created and
           sent to the server.

       MEMCACHED_BEHAVIOR_NOREPLY
           Set this value to specify that you really don't care about the result from your storage commands
           (set, add, replace, append, prepend).

       MEMCACHED_BEHAVIOR_NUMBER_OF_REPLICAS
           If you just want "a poor mans HA", you may specify the numbers of replicas libmemcached should store
           of each item (on different servers).  This replication does not dedicate certain memcached servers to
           store the replicas in, but instead it will store the replicas together with all of the other objects
           (on the 'n' next servers specified in your server list).

       MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ
           Allows randomizing the replica reads starting point. Normally the read is done from primary server
           and in case of miss the read is done from primary + 1, then primary + 2 all the way to 'n' replicas.
           If this option is set on the starting point of the replica reads is randomized between the servers.
           This allows distributing read load to multiple servers with the expense of more write traffic.

       MEMCACHED_BEHAVIOR_CORK
           Enable TCP_CORK behavior. This is only available as an option Linux.  MEMCACHED_NO_SERVERS is
           returned if no servers are available to test with.  MEMCACHED_NOT_SUPPORTED is returned if we were
           not able to determine if support was available. All other responses then MEMCACHED_SUCCESS report an
           error of some sort. This behavior also enables MEMCACHED_BEHAVIOR_TCP_NODELAY when set.

       MEMCACHED_BEHAVIOR_KEEPALIVE
           Enable TCP_KEEPALIVE behavior.

       MEMCACHED_BEHAVIOR_KEEPALIVE_IDLE
           Specify time, in seconds, to mark a connection as idle. This is only available as an option Linux.

       MEMCACHED_BEHAVIOR_SOCKET_SEND_SIZE
           Find the current size of SO_SNDBUF. A value of 0 means either an error occurred or no hosts were
           available. It is safe to assume system default if this occurs.

       MEMCACHED_BEHAVIOR_SOCKET_RECV_SIZE
           Find the current size of SO_RCVBUF. A value of 0 means either an error occurred or no hosts were
           available. It is safe to assume system default if this occurs.

       MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT
           This number of times a host can have an error before it is disabled.

       MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS
           If enabled any hosts which have been flagged as disabled will be removed from the list of servers in
           the memcached_st structure. This must be used in combination with
           MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT.

       MEMCACHED_BEHAVIOR_RETRY_TIMEOUT
           When enabled a host which is problematic will only be checked for usage based on the amount of time
           set by this behavior.

RETURN

       memcached_behavior_get() returns either the current value of the get, or 0 or 1 on simple flag behaviors
       (1 being enabled). memcached_behavior_set() returns failure or success.

NOTES

       memcached_behavior_set() in version .17 was changed from taking a pointer to data value, to taking a
       uin64_t.

HOME

       To find out more information please check: <https://launchpad.net/libmemcached>

AUTHOR

       Brian Aker, <brian@tangent.org>

SEE ALSO

       memcached(1) libmemcached(3) memcached_strerror(3)