git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/get.cc

   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  Libmemcached library
   4  *
   5  *  Copyright (C) 2011-2013 Data Differential, http://datadifferential.com/
   6  *  Copyright (C) 2006-2009 Brian Aker All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions are
  10  *  met:
  11  *
  12  *      * Redistributions of source code must retain the above copyright
  13  *  notice, this list of conditions and the following disclaimer.
  14  *
  15  *      * Redistributions in binary form must reproduce the above
  16  *  copyright notice, this list of conditions and the following disclaimer
  17  *  in the documentation and/or other materials provided with the
  18  *  distribution.
  19  *
  20  *      * The names of its contributors may not be used to endorse or
  21  *  promote products derived from this software without specific prior
  22  *  written permission.
  23  *
  24  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  27  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  28  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  30  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  34  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  */
  37
  38 #include <libmemcached/common.h>
  39
  40 /*
  41   What happens if no servers exist?
  42 */
  43 char *memcached_get(memcached_st *ptr, const char *key,
  44                     size_t key_length,
  45                     size_t *value_length,
  46                     uint32_t *flags,
  47                     memcached_return_t *error)
  48 {
  49   return memcached_get_by_key(ptr, NULL, 0, key, key_length, value_length,
  50                               flags, error);
  51 }
  52
  53 static memcached_return_t memcached_mget_by_key_real(memcached_st *ptr,
  54                                                      const char *group_key,
  55                                                      size_t group_key_length,
  56                                                      const char * const *keys,
  57                                                      const size_t *key_length,
  58                                                      size_t number_of_keys,
  59                                                      bool mget_mode);
  60 char *memcached_get_by_key(memcached_st *shell,
  61                            const char *group_key,
  62                            size_t group_key_length,
  63                            const char *key, size_t key_length,
  64                            size_t *value_length,
  65                            uint32_t *flags,
  66                            memcached_return_t *error)
  67 {
  68   Memcached* ptr= memcached2Memcached(shell);
  69   memcached_return_t unused;
  70   if (error == NULL)
  71   {
  72     error= &unused;
  73   }
  74
  75   uint64_t query_id= 0;
  76   if (ptr)
  77   {
  78     query_id= ptr->query_id;
  79   }
  80
  81   /* Request the key */
  82   *error= memcached_mget_by_key_real(ptr, group_key, group_key_length,
  83                                      (const char * const *)&key, &key_length,
  84                                      1, false);
  85   if (ptr)
  86   {
  87     assert_msg(ptr->query_id == query_id +1, "Programmer error, the query_id was not incremented.");
  88   }
  89
  90   if (memcached_failed(*error))
  91   {
  92     if (ptr)
  93     {
  94       if (memcached_has_current_error(*ptr)) // Find the most accurate error
  95       {
  96         *error= memcached_last_error(ptr);
  97       }
  98     }
  99
 100     if (value_length)
 101     {
 102       *value_length= 0;
 103     }
 104
 105     return NULL;
 106   }
 107
 108   char *value= memcached_fetch(ptr, NULL, NULL,
 109                                value_length, flags, error);
 110   assert_msg(ptr->query_id == query_id +1, "Programmer error, the query_id was not incremented.");
 111
 112   /* This is for historical reasons */
 113   if (*error == MEMCACHED_END)
 114   {
 115     *error= MEMCACHED_NOTFOUND;
 116   }
 117
 118   if (value == NULL)
 119   {
 120     if (ptr->get_key_failure and *error == MEMCACHED_NOTFOUND)
 121     {
 122       memcached_result_st key_failure_result;
 123       memcached_result_st* result_ptr= memcached_result_create(ptr, &key_failure_result);
 124       memcached_return_t rc= ptr->get_key_failure(ptr, key, key_length, result_ptr);
 125
 126       /* On all failure drop to returning NULL */
 127       if (rc == MEMCACHED_SUCCESS or rc == MEMCACHED_BUFFERED)
 128       {
 129         if (rc == MEMCACHED_BUFFERED)
 130         {
 131           uint64_t latch; /* We use latch to track the state of the original socket */
 132           latch= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS);
 133           if (latch == 0)
 134           {
 135             memcached_behavior_set(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS, 1);
 136           }
 137
 138           rc= memcached_set(ptr, key, key_length,
 139                             (memcached_result_value(result_ptr)),
 140                             (memcached_result_length(result_ptr)),
 141                             0,
 142                             (memcached_result_flags(result_ptr)));
 143
 144           if (rc == MEMCACHED_BUFFERED and latch == 0)
 145           {
 146             memcached_behavior_set(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS, 0);
 147           }
 148         }
 149         else
 150         {
 151           rc= memcached_set(ptr, key, key_length,
 152                             (memcached_result_value(result_ptr)),
 153                             (memcached_result_length(result_ptr)),
 154                             0,
 155                             (memcached_result_flags(result_ptr)));
 156         }
 157
 158         if (rc == MEMCACHED_SUCCESS or rc == MEMCACHED_BUFFERED)
 159         {
 160           *error= rc;
 161           *value_length= memcached_result_length(result_ptr);
 162           *flags= memcached_result_flags(result_ptr);
 163           char *result_value=  memcached_string_take_value(&result_ptr->value);
 164           memcached_result_free(result_ptr);
 165
 166           return result_value;
 167         }
 168       }
 169
 170       memcached_result_free(result_ptr);
 171     }
 172     assert_msg(ptr->query_id == query_id +1, "Programmer error, the query_id was not incremented.");
 173
 174     return NULL;
 175   }
 176
 177   return value;
 178 }
 179
 180 memcached_return_t memcached_mget(memcached_st *ptr,
 181                                   const char * const *keys,
 182                                   const size_t *key_length,
 183                                   size_t number_of_keys)
 184 {
 185   return memcached_mget_by_key(ptr, NULL, 0, keys, key_length, number_of_keys);
 186 }
 187
 188 static memcached_return_t binary_mget_by_key(memcached_st *ptr,
 189                                              uint32_t master_server_key,
 190                                              bool is_group_key_set,
 191                                              const char * const *keys,
 192                                              const size_t *key_length,
 193                                              size_t number_of_keys,
 194                                              bool mget_mode);
 195
 196 static memcached_return_t memcached_mget_by_key_real(memcached_st *ptr,
 197                                                      const char *group_key,
 198                                                      size_t group_key_length,
 199                                                      const char * const *keys,
 200                                                      const size_t *key_length,
 201                                                      size_t number_of_keys,
 202                                                      bool mget_mode)
 203 {
 204   bool failures_occured_in_sending= false;
 205   const char *get_command= "get";
 206   uint8_t get_command_length= 3;
 207   unsigned int master_server_key= (unsigned int)-1; /* 0 is a valid server id! */
 208
 209   memcached_return_t rc;
 210   if (memcached_failed(rc= initialize_query(ptr, true)))
 211   {
 212     return rc;
 213   }
 214
 215   if (memcached_is_udp(ptr))
 216   {
 217     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT);
 218   }
 219
 220   LIBMEMCACHED_MEMCACHED_MGET_START();
 221
 222   if (number_of_keys == 0)
 223   {
 224     return memcached_set_error(*ptr, MEMCACHED_NOTFOUND, MEMCACHED_AT, memcached_literal_param("number_of_keys was zero"));
 225   }
 226
 227   if (memcached_failed(memcached_key_test(*ptr, keys, key_length, number_of_keys)))
 228   {
 229     return memcached_last_error(ptr);
 230   }
 231
 232   bool is_group_key_set= false;
 233   if (group_key and group_key_length)
 234   {
 235     master_server_key= memcached_generate_hash_with_redistribution(ptr, group_key, group_key_length);
 236     is_group_key_set= true;
 237   }
 238
 239   /*
 240     Here is where we pay for the non-block API. We need to remove any data sitting
 241     in the queue before we start our get.
 242
 243     It might be optimum to bounce the connection if count > some number.
 244   */
 245   for (uint32_t x= 0; x < memcached_server_count(ptr); x++)
 246   {
 247     org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, x);
 248
 249     if (instance->response_count())
 250     {
 251       char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
 252
 253       if (ptr->flags.no_block)
 254       {
 255         memcached_io_write(instance);
 256       }
 257
 258       while(instance->response_count())
 259       {
 260         (void)memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, &ptr->result);
 261       }
 262     }
 263   }
 264
 265   if (memcached_is_binary(ptr))
 266   {
 267     return binary_mget_by_key(ptr, master_server_key, is_group_key_set, keys,
 268                               key_length, number_of_keys, mget_mode);
 269   }
 270
 271   if (ptr->flags.support_cas)
 272   {
 273     get_command= "gets";
 274     get_command_length= 4;
 275   }
 276
 277   /*
 278     If a server fails we warn about errors and start all over with sending keys
 279     to the server.
 280   */
 281   WATCHPOINT_ASSERT(rc == MEMCACHED_SUCCESS);
 282   size_t hosts_connected= 0;
 283   for (uint32_t x= 0; x < number_of_keys; x++)
 284   {
 285     uint32_t server_key;
 286
 287     if (is_group_key_set)
 288     {
 289       server_key= master_server_key;
 290     }
 291     else
 292     {
 293       server_key= memcached_generate_hash_with_redistribution(ptr, keys[x], key_length[x]);
 294     }
 295
 296     org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, server_key);
 297
 298     libmemcached_io_vector_st vector[]=
 299     {
 300       { get_command, get_command_length },
 301       { memcached_literal_param(" ") },
 302       { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 303       { keys[x], key_length[x] }
 304     };
 305
 306
 307     if (instance->response_count() == 0)
 308     {
 309       rc= memcached_connect(instance);
 310
 311       if (memcached_failed(rc))
 312       {
 313         memcached_set_error(*instance, rc, MEMCACHED_AT);
 314         continue;
 315       }
 316       hosts_connected++;
 317
 318       if ((memcached_io_writev(instance, vector, 1, false)) == false)
 319       {
 320         failures_occured_in_sending= true;
 321         continue;
 322       }
 323       WATCHPOINT_ASSERT(instance->cursor_active_ == 0);
 324       memcached_instance_response_increment(instance);
 325       WATCHPOINT_ASSERT(instance->cursor_active_ == 1);
 326     }
 327
 328     {
 329       if ((memcached_io_writev(instance, (vector + 1), 3, false)) == false)
 330       {
 331         memcached_instance_response_reset(instance);
 332         failures_occured_in_sending= true;
 333         continue;
 334       }
 335     }
 336   }
 337
 338   if (hosts_connected == 0)
 339   {
 340     LIBMEMCACHED_MEMCACHED_MGET_END();
 341
 342     if (memcached_failed(rc))
 343     {
 344       return rc;
 345     }
 346
 347     return memcached_set_error(*ptr, MEMCACHED_NO_SERVERS, MEMCACHED_AT);
 348   }
 349
 350
 351   /*
 352     Should we muddle on if some servers are dead?
 353   */
 354   bool success_happened= false;
 355   for (uint32_t x= 0; x < memcached_server_count(ptr); x++)
 356   {
 357     org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, x);
 358
 359     if (instance->response_count())
 360     {
 361       /* We need to do something about non-connnected hosts in the future */
 362       if ((memcached_io_write(instance, "\r\n", 2, true)) == -1)
 363       {
 364         failures_occured_in_sending= true;
 365       }
 366       else
 367       {
 368         success_happened= true;
 369       }
 370     }
 371   }
 372
 373   LIBMEMCACHED_MEMCACHED_MGET_END();
 374
 375   if (failures_occured_in_sending and success_happened)
 376   {
 377     return MEMCACHED_SOME_ERRORS;
 378   }
 379
 380   if (success_happened)
 381   {
 382     return MEMCACHED_SUCCESS;
 383   }
 384
 385   return MEMCACHED_FAILURE; // Complete failure occurred
 386 }
 387
 388 memcached_return_t memcached_mget_by_key(memcached_st *shell,
 389                                          const char *group_key,
 390                                          size_t group_key_length,
 391                                          const char * const *keys,
 392                                          const size_t *key_length,
 393                                          size_t number_of_keys)
 394 {
 395   Memcached* ptr= memcached2Memcached(shell);
 396   return memcached_mget_by_key_real(ptr, group_key, group_key_length, keys,
 397                                     key_length, number_of_keys, true);
 398 }
 399
 400 memcached_return_t memcached_mget_execute(memcached_st *ptr,
 401                                           const char * const *keys,
 402                                           const size_t *key_length,
 403                                           size_t number_of_keys,
 404                                           memcached_execute_fn *callback,
 405                                           void *context,
 406                                           unsigned int number_of_callbacks)
 407 {
 408   return memcached_mget_execute_by_key(ptr, NULL, 0, keys, key_length,
 409                                        number_of_keys, callback,
 410                                        context, number_of_callbacks);
 411 }
 412
 413 memcached_return_t memcached_mget_execute_by_key(memcached_st *shell,
 414                                                  const char *group_key,
 415                                                  size_t group_key_length,
 416                                                  const char * const *keys,
 417                                                  const size_t *key_length,
 418                                                  size_t number_of_keys,
 419                                                  memcached_execute_fn *callback,
 420                                                  void *context,
 421                                                  unsigned int number_of_callbacks)
 422 {
 423   Memcached* ptr= memcached2Memcached(shell);
 424   memcached_return_t rc;
 425   if (memcached_failed(rc= initialize_query(ptr, false)))
 426   {
 427     return rc;
 428   }
 429
 430   if (memcached_is_udp(ptr))
 431   {
 432     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT);
 433   }
 434
 435   if (memcached_is_binary(ptr) == false)
 436   {
 437     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT,
 438                                memcached_literal_param("ASCII protocol is not supported for memcached_mget_execute_by_key()"));
 439   }
 440
 441   memcached_callback_st *original_callbacks= ptr->callbacks;
 442   memcached_callback_st cb= {
 443     callback,
 444     context,
 445     number_of_callbacks
 446   };
 447
 448   ptr->callbacks= &cb;
 449   rc= memcached_mget_by_key(ptr, group_key, group_key_length, keys,
 450                             key_length, number_of_keys);
 451   ptr->callbacks= original_callbacks;
 452   return rc;
 453 }
 454
 455 static memcached_return_t simple_binary_mget(memcached_st *ptr,
 456                                              uint32_t master_server_key,
 457                                              bool is_group_key_set,
 458                                              const char * const *keys,
 459                                              const size_t *key_length,
 460                                              size_t number_of_keys, bool mget_mode)
 461 {
 462   memcached_return_t rc= MEMCACHED_NOTFOUND;
 463
 464   bool flush= (number_of_keys == 1);
 465
 466   /*
 467     If a server fails we warn about errors and start all over with sending keys
 468     to the server.
 469   */
 470   for (uint32_t x= 0; x < number_of_keys; ++x)
 471   {
 472     uint32_t server_key;
 473
 474     if (is_group_key_set)
 475     {
 476       server_key= master_server_key;
 477     }
 478     else
 479     {
 480       server_key= memcached_generate_hash_with_redistribution(ptr, keys[x], key_length[x]);
 481     }
 482
 483     org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, server_key);
 484
 485     if (instance->response_count() == 0)
 486     {
 487       rc= memcached_connect(instance);
 488       if (memcached_failed(rc))
 489       {
 490         continue;
 491       }
 492     }
 493
 494     protocol_binary_request_getk request= { }; //= {.bytes= {0}};
 495     initialize_binary_request(instance, request.message.header);
 496     if (mget_mode)
 497     {
 498       request.message.header.request.opcode= PROTOCOL_BINARY_CMD_GETKQ;
 499     }
 500     else
 501     {
 502       request.message.header.request.opcode= PROTOCOL_BINARY_CMD_GETK;
 503     }
 504
 505     {
 506       memcached_return_t vk= memcached_validate_key_length(key_length[x], ptr->flags.binary_protocol);
 507       if (vk != MEMCACHED_SUCCESS)
 508       {
 509         if (x > 0)
 510         {
 511           memcached_io_reset(instance);
 512         }
 513
 514         return vk;
 515       }
 516     }
 517
 518     request.message.header.request.keylen= htons((uint16_t)(key_length[x] + memcached_array_size(ptr->_namespace)));
 519     request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 520     request.message.header.request.bodylen= htonl((uint32_t)( key_length[x] + memcached_array_size(ptr->_namespace)));
 521
 522     libmemcached_io_vector_st vector[]=
 523     {
 524       { request.bytes, sizeof(request.bytes) },
 525       { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 526       { keys[x], key_length[x] }
 527     };
 528
 529     if (memcached_io_writev(instance, vector, 3, flush) == false)
 530     {
 531       memcached_server_response_reset(instance);
 532       rc= MEMCACHED_SOME_ERRORS;
 533       continue;
 534     }
 535
 536     /* We just want one pending response per server */
 537     memcached_server_response_reset(instance);
 538     memcached_server_response_increment(instance);
 539     if ((x > 0 and x == ptr->io_key_prefetch) and memcached_flush_buffers(ptr) != MEMCACHED_SUCCESS)
 540     {
 541       rc= MEMCACHED_SOME_ERRORS;
 542     }
 543   }
 544
 545   if (mget_mode)
 546   {
 547     /*
 548       Send a noop command to flush the buffers
 549     */
 550     protocol_binary_request_noop request= {}; //= {.bytes= {0}};
 551     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_NOOP;
 552     request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 553
 554     for (uint32_t x= 0; x < memcached_server_count(ptr); ++x)
 555     {
 556       org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, x);
 557       initialize_binary_request(instance, request.message.header);
 558
 559       if (instance->response_count())
 560       {
 561         if ((memcached_io_write(instance) == false) or
 562             (memcached_io_write(instance, request.bytes, sizeof(request.bytes), true) == -1))
 563         {
 564           memcached_instance_response_reset(instance);
 565           memcached_io_reset(instance);
 566           rc= MEMCACHED_SOME_ERRORS;
 567         }
 568       }
 569     }
 570   }
 571
 572
 573   return rc;
 574 }
 575
 576 static memcached_return_t replication_binary_mget(memcached_st *ptr,
 577                                                   uint32_t* hash,
 578                                                   bool* dead_servers,
 579                                                   const char *const *keys,
 580                                                   const size_t *key_length,
 581                                                   size_t number_of_keys)
 582 {
 583   memcached_return_t rc= MEMCACHED_NOTFOUND;
 584   uint32_t start= 0;
 585   uint64_t randomize_read= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ);
 586
 587   if (randomize_read)
 588   {
 589     start= (uint32_t)random() % (uint32_t)(ptr->number_of_replicas + 1);
 590   }
 591
 592   /* Loop for each replica */
 593   for (uint32_t replica= 0; replica <= ptr->number_of_replicas; ++replica)
 594   {
 595     bool success= true;
 596
 597     for (uint32_t x= 0; x < number_of_keys; ++x)
 598     {
 599       if (hash[x] == memcached_server_count(ptr))
 600       {
 601         continue; /* Already successfully sent */
 602       }
 603
 604       uint32_t server= hash[x] +replica;
 605
 606       /* In case of randomized reads */
 607       if (randomize_read and ((server + start) <= (hash[x] + ptr->number_of_replicas)))
 608       {
 609         server+= start;
 610       }
 611
 612       while (server >= memcached_server_count(ptr))
 613       {
 614         server -= memcached_server_count(ptr);
 615       }
 616
 617       if (dead_servers[server])
 618       {
 619         continue;
 620       }
 621
 622       org::libmemcached::Instance* instance= memcached_instance_fetch(ptr, server);
 623
 624       if (instance->response_count() == 0)
 625       {
 626         rc= memcached_connect(instance);
 627
 628         if (memcached_failed(rc))
 629         {
 630           memcached_io_reset(instance);
 631           dead_servers[server]= true;
 632           success= false;
 633           continue;
 634         }
 635       }
 636
 637       protocol_binary_request_getk request= {};
 638       initialize_binary_request(instance, request.message.header);
 639       request.message.header.request.opcode= PROTOCOL_BINARY_CMD_GETK;
 640       request.message.header.request.keylen= htons((uint16_t)(key_length[x] + memcached_array_size(ptr->_namespace)));
 641       request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 642       request.message.header.request.bodylen= htonl((uint32_t)(key_length[x] + memcached_array_size(ptr->_namespace)));
 643
 644       /*
 645        * We need to disable buffering to actually know that the request was
 646        * successfully sent to the server (so that we should expect a result
 647        * back). It would be nice to do this in buffered mode, but then it
 648        * would be complex to handle all error situations if we got to send
 649        * some of the messages, and then we failed on writing out some others
 650        * and we used the callback interface from memcached_mget_execute so
 651        * that we might have processed some of the responses etc. For now,
 652        * just make sure we work _correctly_
 653      */
 654       libmemcached_io_vector_st vector[]=
 655       {
 656         { request.bytes, sizeof(request.bytes) },
 657         { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 658         { keys[x], key_length[x] }
 659       };
 660
 661       if (memcached_io_writev(instance, vector, 3, true) == false)
 662       {
 663         memcached_io_reset(instance);
 664         dead_servers[server]= true;
 665         success= false;
 666         continue;
 667       }
 668
 669       memcached_server_response_increment(instance);
 670       hash[x]= memcached_server_count(ptr);
 671     }
 672
 673     if (success)
 674     {
 675       break;
 676     }
 677   }
 678
 679   return rc;
 680 }
 681
 682 static memcached_return_t binary_mget_by_key(memcached_st *ptr,
 683                                              uint32_t master_server_key,
 684                                              bool is_group_key_set,
 685                                              const char * const *keys,
 686                                              const size_t *key_length,
 687                                              size_t number_of_keys,
 688                                              bool mget_mode)
 689 {
 690   if (ptr->number_of_replicas == 0)
 691   {
 692     return simple_binary_mget(ptr, master_server_key, is_group_key_set,
 693                               keys, key_length, number_of_keys, mget_mode);
 694   }
 695
 696   uint32_t* hash= libmemcached_xvalloc(ptr, number_of_keys, uint32_t);
 697   bool* dead_servers= libmemcached_xcalloc(ptr, memcached_server_count(ptr), bool);
 698
 699   if (hash == NULL or dead_servers == NULL)
 700   {
 701     libmemcached_free(ptr, hash);
 702     libmemcached_free(ptr, dead_servers);
 703     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 704   }
 705
 706   if (is_group_key_set)
 707   {
 708     for (size_t x= 0; x < number_of_keys; x++)
 709     {
 710       hash[x]= master_server_key;
 711     }
 712   }
 713   else
 714   {
 715     for (size_t x= 0; x < number_of_keys; x++)
 716     {
 717       hash[x]= memcached_generate_hash_with_redistribution(ptr, keys[x], key_length[x]);
 718     }
 719   }
 720
 721   memcached_return_t rc= replication_binary_mget(ptr, hash, dead_servers, keys,
 722                                                  key_length, number_of_keys);
 723
 724   WATCHPOINT_IFERROR(rc);
 725   libmemcached_free(ptr, hash);
 726   libmemcached_free(ptr, dead_servers);
 727
 728   return MEMCACHED_SUCCESS;
 729 }