Provided by: libmemcached-dev_1.0.18-4.2ubuntu0.18.04.1_amd64 bug

NAME

       memcached_behavior_get - libmemcached Documentation

       Manipulate the behavior of a memcached_st structure.

SYNOPSIS

       #include <libmemcached/memcached.h>

       memcached_behavior_t

       uint64_t memcached_behavior_get(memcached_st *ptr, memcached_behavior_t flag)

       memcached_return_t   memcached_behavior_set(memcached_st *ptr,  memcached_behavior_t flag,
       uint64_t data)

       Compile and link with -lmemcached

DESCRIPTION

       libmemcached(3) behavior  can  be  modified  by  using  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 testsed 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_fetch_execute().

       All  other  operations  are testsed 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  tests  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

       Deprecated since version 0.46(?): DNS lookups are now always cached until an error  occurs
       with the server.

       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 tests.  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 must
       be  passed  to  memcached_behavior_set  to  change this value (this requires casting). For
       memcached_behavior_get a signed int value will be cast and returned as the  unsigned  long
       long.

       MEMCACHED_BEHAVIOR_USER_DATA

       Deprecated since version <: 0.30

       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  in
       milliseconds. Specifying -1 means an infinite timeā€out.

       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

       This open has been deprecated with the  behavior  now  built  and  used  appropriately  on
       selected platforms.

       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 occured or no hosts
       were available. It is safe to assume system default if this occurs. If an error occurs you
       can checked the last cached errno statement to find the specific error.

       MEMCACHED_BEHAVIOR_SOCKET_RECV_SIZE

       Find the current size of SO_RCVBUF. A value of 0 means either an error occured or no hosts
       were available. It is safe to assume system default if this occurs. If an error occurs you
       can checked the last cached errno statement to find the specific error.

       MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT

       Deprecated since version 0.48: See MEMCACHED_BEHAVIOR_REMOVE_FAILED_SERVERS

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

       MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS

       Deprecated since version 0.48: See MEMCACHED_BEHAVIOR_REMOVE_FAILED_SERVERS

       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_REMOVE_FAILED_SERVERS
              If enabled any hosts which have been flagged as disabled will be removed  from  the
              list of servers in the memcached_st structure.

       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. The value is in seconds.

       MEMCACHED_BEHAVIOR_HASH_WITH_PREFIX_KEY

       When enabled the prefix key will be added to the key when determining server by hash.  See
       MEMCACHED_CALLBACK_NAMESPACE for additional information.

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: http://libmemcached.org/

SEE ALSO

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

AUTHOR

       Brian Aker

COPYRIGHT

       2011-2013, Brian Aker DataDifferential, http://datadifferential.com/