git.m6w6.name Git - awesomized/libmemcached/blob - docs/man/memcached_behavior_get.3

   1 .TH "MEMCACHED_BEHAVIOR_GET" "3" "June 02, 2011" "0.47" "libmemcached"
   2 .SH NAME
   3 memcached_behavior_get \- libmemcached Documentation
   4 .
   5 .nr rst2man-indent-level 0
   6 .
   7 .de1 rstReportMargin
   8 \\$1 \\n[an-margin]
   9 level \\n[rst2man-indent-level]
  10 level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
  11 -
  12 \\n[rst2man-indent0]
  13 \\n[rst2man-indent1]
  14 \\n[rst2man-indent2]
  15 ..
  16 .de1 INDENT
  17 .\" .rstReportMargin pre:
  18 . RS \\$1
  19 . nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin]
  20 . nr rst2man-indent-level +1
  21 .\" .rstReportMargin post:
  22 ..
  23 .de UNINDENT
  24 . RE
  25 .\" indent \\n[an-margin]
  26 .\" old: \\n[rst2man-indent\\n[rst2man-indent-level]]
  27 .nr rst2man-indent-level -1
  28 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
  29 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
  30 ..
  31 .\" Man page generated from reStructeredText.
  32 .
  33 .sp
  34 Manipulate the behavior of a memcached_st structure.
  35 .SH SYNOPSIS
  36 .sp
  37 #include <libmemcached/memcached.h>
  38 .INDENT 0.0
  39 .TP
  40 .B uint64_t memcached_behavior_get (memcached_st *ptr, memcached_behavior flag);
  41 .UNINDENT
  42 .INDENT 0.0
  43 .TP
  44 .B memcached_return_t memcached_behavior_set (memcached_st *ptr, memcached_behavior flag, uint64_t data);
  45 .UNINDENT
  46 .sp
  47 Compile and link with \-lmemcached
  48 .SH DESCRIPTION
  49 .sp
  50 \fIlibmemcached(3)\fP behavior can be modified by use memcached_behavior_set().
  51 Default behavior is the library strives to be quick and accurate. Some
  52 behavior, while being faster, can also result in not entirely accurate
  53 behavior (for instance, memcached_set() will always respond with
  54 \fBMEMCACHED_SUCCESS\fP).
  55 .sp
  56 memcached_behavior_get() takes a behavior flag and returns whether or not
  57 that behavior is currently enabled in the client.
  58 .sp
  59 memcached_behavior_set() changes the value of a particular option of the
  60 client. It takes both a flag (listed below) and a value. For simple on or
  61 off options you just need to pass in a value of 1. Calls to
  62 memcached_behavior_set() will flush and reset all connections.
  63 .INDENT 0.0
  64 .TP
  65 .B MEMCACHED_BEHAVIOR_USE_UDP
  66 .UNINDENT
  67 .sp
  68 Causes \fIlibmemcached(3)\fP to use the UDP transport when communicating
  69 with a memcached server. Not all I/O operations are testsed
  70 when this behavior is enababled. The following operations will return
  71 \fBMEMCACHED_NOT_SUPPORTED\fP when executed with the MEMCACHED_BEHAVIOR_USE_UDP
  72 enabled: memcached_version(), memcached_stat(), memcached_get(),
  73 memcached_get_by_key(), memcached_mget(), memcached_mget_by_key(),
  74 memcached_fetch(), memcached_fetch_result(), memcached_value_fetch().
  75 .sp
  76 All other operations are testsed but are executed in a \(aqfire\-and\-forget\(aq
  77 mode, in which once the client has executed the operation, no attempt
  78 will be made to ensure the operation has been received and acted on by the
  79 server.
  80 .sp
  81 \fIlibmemcached(3)\fP does not allow TCP and UDP servers to be shared within
  82 the same libmemached(3) client \(aqinstance\(aq. An attempt to add a TCP server
  83 when this behavior is enabled will result in a \fBMEMCACHED_INVALID_HOST_PROTOCOL\fP,
  84 as will attempting to add a UDP server when this behavior has not been enabled.
  85 .INDENT 0.0
  86 .TP
  87 .B MEMCACHED_BEHAVIOR_NO_BLOCK
  88 .UNINDENT
  89 .sp
  90 Causes \fIlibmemcached(3)\fP to use asychronous IO. This is the fastest transport
  91 available for storage functions.
  92 .INDENT 0.0
  93 .TP
  94 .B MEMCACHED_BEHAVIOR_SND_TIMEOUT
  95 .UNINDENT
  96 .sp
  97 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.
  98 .INDENT 0.0
  99 .TP
 100 .B MEMCACHED_BEHAVIOR_RCV_TIMEOUT
 101 .UNINDENT
 102 .sp
 103 This sets the microsecond behavior of the socket against the SO_RCVTIMEO flag.
 104 .sp
 105 In cases where you cannot use non\-blocking IO this will allow you to still have timeouts on the reading of data.
 106 .INDENT 0.0
 107 .TP
 108 .B MEMCACHED_BEHAVIOR_TCP_NODELAY
 109 .UNINDENT
 110 .sp
 111 Turns on the no\-delay feature for connecting sockets (may be faster in some
 112 environments).
 113 .INDENT 0.0
 114 .TP
 115 .B MEMCACHED_BEHAVIOR_HASH
 116 .UNINDENT
 117 .sp
 118 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.
 119 .sp
 120 Each hash has it\(aqs advantages and it\(aqs weaknesses. If you don\(aqt know or don\(aqt care, just go with the default.
 121 .sp
 122 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.
 123 .INDENT 0.0
 124 .TP
 125 .B MEMCACHED_BEHAVIOR_DISTRIBUTION
 126 .UNINDENT
 127 .sp
 128 Using this you can enable different means of distributing values to servers.
 129 .sp
 130 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.
 131 .INDENT 0.0
 132 .TP
 133 .B MEMCACHED_BEHAVIOR_CACHE_LOOKUPS
 134 .UNINDENT
 135 .sp
 136 DEPRECATED. Memcached can cache named lookups so that DNS lookups are made only once.
 137 .INDENT 0.0
 138 .TP
 139 .B MEMCACHED_BEHAVIOR_SUPPORT_CAS
 140 .UNINDENT
 141 .sp
 142 Support CAS operations (this is not enabled by default at this point in the server since it imposes a slight performance penalty).
 143 .INDENT 0.0
 144 .TP
 145 .B MEMCACHED_BEHAVIOR_KETAMA
 146 .UNINDENT
 147 .sp
 148 Sets the default distribution to MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA and the hash to MEMCACHED_HASH_MD5.
 149 .INDENT 0.0
 150 .TP
 151 .B MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED
 152 .UNINDENT
 153 .sp
 154 Sets the default distribution to MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA with the weighted tests.  and the hash to MEMCACHED_HASH_MD5.
 155 .INDENT 0.0
 156 .TP
 157 .B MEMCACHED_BEHAVIOR_KETAMA_HASH
 158 .UNINDENT
 159 .sp
 160 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.
 161 .INDENT 0.0
 162 .TP
 163 .B MEMCACHED_BEHAVIOR_KETAMA_COMPAT
 164 .UNINDENT
 165 .sp
 166 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.
 167 .INDENT 0.0
 168 .TP
 169 .B MEMCACHED_BEHAVIOR_POLL_TIMEOUT
 170 .UNINDENT
 171 .sp
 172 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.
 173 .INDENT 0.0
 174 .TP
 175 .B MEMCACHED_BEHAVIOR_USER_DATA
 176 .UNINDENT
 177 .sp
 178 DEPRECATED
 179 .INDENT 0.0
 180 .TP
 181 .B MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
 182 .UNINDENT
 183 .sp
 184 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.
 185 .INDENT 0.0
 186 .TP
 187 .B MEMCACHED_BEHAVIOR_VERIFY_KEY
 188 .UNINDENT
 189 .sp
 190 Enabling this will cause \fIlibmemcached(3)\fP to test all keys to verify that they are valid keys.
 191 .INDENT 0.0
 192 .TP
 193 .B MEMCACHED_BEHAVIOR_SORT_HOSTS
 194 .UNINDENT
 195 .sp
 196 Enabling this will cause hosts that are added to be placed in the host list in sorted order. This will defeat consisten hashing.
 197 .INDENT 0.0
 198 .TP
 199 .B MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT
 200 .UNINDENT
 201 .sp
 202 In non\-blocking mode this changes the value of the timeout during socket connection.
 203 .INDENT 0.0
 204 .TP
 205 .B MEMCACHED_BEHAVIOR_BINARY_PROTOCOL
 206 .UNINDENT
 207 .sp
 208 Enable the use of the binary protocol. Please note that you cannot toggle this flag on an open connection.
 209 .INDENT 0.0
 210 .TP
 211 .B MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT
 212 .UNINDENT
 213 .sp
 214 Set this value to enable the server be removed after continuous MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT times connection failure.
 215 .INDENT 0.0
 216 .TP
 217 .B MEMCACHED_BEHAVIOR_IO_MSG_WATERMARK
 218 .UNINDENT
 219 .sp
 220 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).
 221 .INDENT 0.0
 222 .TP
 223 .B MEMCACHED_BEHAVIOR_IO_BYTES_WATERMARK
 224 .UNINDENT
 225 .sp
 226 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).
 227 .INDENT 0.0
 228 .TP
 229 .B MEMCACHED_BEHAVIOR_IO_KEY_PREFETCH
 230 .UNINDENT
 231 .sp
 232 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.
 233 .INDENT 0.0
 234 .TP
 235 .B MEMCACHED_BEHAVIOR_NOREPLY
 236 .UNINDENT
 237 .sp
 238 Set this value to specify that you really don\(aqt care about the result from your storage commands (set, add, replace, append, prepend).
 239 .INDENT 0.0
 240 .TP
 241 .B MEMCACHED_BEHAVIOR_NUMBER_OF_REPLICAS
 242 .UNINDENT
 243 .sp
 244 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 \(aqn\(aq next servers specified in your server list).
 245 .INDENT 0.0
 246 .TP
 247 .B MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ
 248 .UNINDENT
 249 .sp
 250 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 \(aqn\(aq 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.
 251 .INDENT 0.0
 252 .TP
 253 .B MEMCACHED_BEHAVIOR_CORK
 254 .UNINDENT
 255 .sp
 256 This open has been deprecated with the behavior now built and used appropriately on selected platforms.
 257 .INDENT 0.0
 258 .TP
 259 .B MEMCACHED_BEHAVIOR_KEEPALIVE
 260 .UNINDENT
 261 .sp
 262 Enable TCP_KEEPALIVE behavior.
 263 .INDENT 0.0
 264 .TP
 265 .B MEMCACHED_BEHAVIOR_KEEPALIVE_IDLE
 266 .UNINDENT
 267 .sp
 268 Specify time, in seconds, to mark a connection as idle. This is only available as an option Linux.
 269 .INDENT 0.0
 270 .TP
 271 .B MEMCACHED_BEHAVIOR_SOCKET_SEND_SIZE
 272 .UNINDENT
 273 .sp
 274 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.
 275 .INDENT 0.0
 276 .TP
 277 .B MEMCACHED_BEHAVIOR_SOCKET_RECV_SIZE
 278 .UNINDENT
 279 .sp
 280 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.
 281 .INDENT 0.0
 282 .TP
 283 .B MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT
 284 .UNINDENT
 285 .sp
 286 DEPRECATED, please see MEMCACHED_BEHAVIOR_REMOVE_FAILED_SERVERS. This number of times a host can have an error before it is disabled.
 287 .INDENT 0.0
 288 .TP
 289 .B MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS
 290 .UNINDENT
 291 .sp
 292 DEPRECATED, please 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.
 293 .INDENT 0.0
 294 .TP
 295 .B MEMCACHED_BEHAVIOR_REMOVE_FAILED_SERVERS
 296 .UNINDENT
 297 .sp
 298 If enabled any hosts which have been flagged as disabled will be removed from the list of servers in the memcached_st structure.
 299 .INDENT 0.0
 300 .TP
 301 .B MEMCACHED_BEHAVIOR_RETRY_TIMEOUT
 302 .UNINDENT
 303 .sp
 304 When enabled a host which is problematic will only be checked for usage based on the amount of time set by this behavior.
 305 .INDENT 0.0
 306 .TP
 307 .B MEMCACHED_BEHAVIOR_HASH_WITH_PREFIX_KEY
 308 .UNINDENT
 309 .sp
 310 When enabled the prefix key will be added to the key when determining server by hash.
 311 .SH RETURN
 312 .sp
 313 memcached_behavior_get() returns either the current value of the get, or 0
 314 or 1 on simple flag behaviors (1 being enabled). memcached_behavior_set()
 315 returns failure or success.
 316 .SH NOTES
 317 .sp
 318 memcached_behavior_set() in version .17 was changed from taking a pointer
 319 to data value, to taking a uin64_t.
 320 .SH HOME
 321 .sp
 322 To find out more information please check:
 323 \fI\%http://libmemcached.org/\fP
 324 .SH SEE ALSO
 325 .sp
 326 \fImemcached(1)\fP \fIlibmemcached(3)\fP \fImemcached_strerror(3)\fP
 327 .SH AUTHOR
 328 Brian Aker
 329 .SH COPYRIGHT
 330 2011, Brian Aker DataDifferential, http://datadifferential.com/
 331 .\" Generated by docutils manpage writer.
 332 .\"
 333 .