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) 2011-2012 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
  61 char *memcached_get_by_key(memcached_st *ptr,
  62                            const char *group_key,
  63                            size_t group_key_length,
  64                            const char *key, size_t key_length,
  65                            size_t *value_length,
  66                            uint32_t *flags,
  67                            memcached_return_t *error)
  68 {
  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_reset(&ptr->result);
 123       memcached_return_t rc= ptr->get_key_failure(ptr, key, key_length, &ptr->result);
 124
 125       /* On all failure drop to returning NULL */
 126       if (rc == MEMCACHED_SUCCESS or rc == MEMCACHED_BUFFERED)
 127       {
 128         if (rc == MEMCACHED_BUFFERED)
 129         {
 130           uint64_t latch; /* We use latch to track the state of the original socket */
 131           latch= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS);
 132           if (latch == 0)
 133           {
 134             memcached_behavior_set(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS, 1);
 135           }
 136
 137           rc= memcached_set(ptr, key, key_length,
 138                             (memcached_result_value(&ptr->result)),
 139                             (memcached_result_length(&ptr->result)),
 140                             0,
 141                             (memcached_result_flags(&ptr->result)));
 142
 143           if (rc == MEMCACHED_BUFFERED and latch == 0)
 144           {
 145             memcached_behavior_set(ptr, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS, 0);
 146           }
 147         }
 148         else
 149         {
 150           rc= memcached_set(ptr, key, key_length,
 151                             (memcached_result_value(&ptr->result)),
 152                             (memcached_result_length(&ptr->result)),
 153                             0,
 154                             (memcached_result_flags(&ptr->result)));
 155         }
 156
 157         if (rc == MEMCACHED_SUCCESS or rc == MEMCACHED_BUFFERED)
 158         {
 159           *error= rc;
 160           *value_length= memcached_result_length(&ptr->result);
 161           *flags= memcached_result_flags(&ptr->result);
 162           return memcached_string_take_value(&ptr->result.value);
 163         }
 164       }
 165     }
 166     assert_msg(ptr->query_id == query_id +1, "Programmer error, the query_id was not incremented.");
 167
 168     return NULL;
 169   }
 170
 171   return value;
 172 }
 173
 174 memcached_return_t memcached_mget(memcached_st *ptr,
 175                                   const char * const *keys,
 176                                   const size_t *key_length,
 177                                   size_t number_of_keys)
 178 {
 179   return memcached_mget_by_key(ptr, NULL, 0, keys, key_length, number_of_keys);
 180 }
 181
 182 static memcached_return_t binary_mget_by_key(memcached_st *ptr,
 183                                              uint32_t master_server_key,
 184                                              bool is_group_key_set,
 185                                              const char * const *keys,
 186                                              const size_t *key_length,
 187                                              size_t number_of_keys,
 188                                              bool mget_mode);
 189
 190 static memcached_return_t memcached_mget_by_key_real(memcached_st *ptr,
 191                                                      const char *group_key,
 192                                                      size_t group_key_length,
 193                                                      const char * const *keys,
 194                                                      const size_t *key_length,
 195                                                      size_t number_of_keys,
 196                                                      bool mget_mode)
 197 {
 198   bool failures_occured_in_sending= false;
 199   const char *get_command= "get ";
 200   uint8_t get_command_length= 4;
 201   unsigned int master_server_key= (unsigned int)-1; /* 0 is a valid server id! */
 202
 203   memcached_return_t rc;
 204   if (memcached_failed(rc= initialize_query(ptr, true)))
 205   {
 206     return rc;
 207   }
 208
 209   if (memcached_is_udp(ptr))
 210   {
 211     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT);
 212   }
 213
 214   LIBMEMCACHED_MEMCACHED_MGET_START();
 215
 216   if (number_of_keys == 0)
 217   {
 218     return memcached_set_error(*ptr, MEMCACHED_NOTFOUND, MEMCACHED_AT, memcached_literal_param("number_of_keys was zero"));
 219   }
 220
 221   if (memcached_failed(memcached_key_test(*ptr, keys, key_length, number_of_keys)))
 222   {
 223     return memcached_last_error(ptr);
 224   }
 225
 226   bool is_group_key_set= false;
 227   if (group_key and group_key_length)
 228   {
 229     master_server_key= memcached_generate_hash_with_redistribution(ptr, group_key, group_key_length);
 230     is_group_key_set= true;
 231   }
 232
 233   /*
 234     Here is where we pay for the non-block API. We need to remove any data sitting
 235     in the queue before we start our get.
 236
 237     It might be optimum to bounce the connection if count > some number.
 238   */
 239   for (uint32_t x= 0; x < memcached_server_count(ptr); x++)
 240   {
 241     memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, x);
 242
 243     if (memcached_server_response_count(instance))
 244     {
 245       char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
 246
 247       if (ptr->flags.no_block)
 248       {
 249         memcached_io_write(instance);
 250       }
 251
 252       while(memcached_server_response_count(instance))
 253       {
 254         (void)memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, &ptr->result);
 255       }
 256     }
 257   }
 258
 259   if (memcached_is_binary(ptr))
 260   {
 261     return binary_mget_by_key(ptr, master_server_key, is_group_key_set, keys,
 262                               key_length, number_of_keys, mget_mode);
 263   }
 264
 265   if (ptr->flags.support_cas)
 266   {
 267     get_command= "gets ";
 268     get_command_length= 5;
 269   }
 270
 271   /*
 272     If a server fails we warn about errors and start all over with sending keys
 273     to the server.
 274   */
 275   WATCHPOINT_ASSERT(rc == MEMCACHED_SUCCESS);
 276   size_t hosts_connected= 0;
 277   for (uint32_t x= 0; x < number_of_keys; x++)
 278   {
 279     memcached_server_write_instance_st instance;
 280     uint32_t server_key;
 281
 282     if (is_group_key_set)
 283     {
 284       server_key= master_server_key;
 285     }
 286     else
 287     {
 288       server_key= memcached_generate_hash_with_redistribution(ptr, keys[x], key_length[x]);
 289     }
 290
 291     instance= memcached_server_instance_fetch(ptr, server_key);
 292
 293     libmemcached_io_vector_st vector[]=
 294     {
 295       { get_command, get_command_length },
 296       { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 297       { keys[x], key_length[x] },
 298       { memcached_literal_param(" ") }
 299     };
 300
 301
 302     if (memcached_server_response_count(instance) == 0)
 303     {
 304       rc= memcached_connect(instance);
 305
 306       if (memcached_failed(rc))
 307       {
 308         memcached_set_error(*instance, rc, MEMCACHED_AT);
 309         continue;
 310       }
 311       hosts_connected++;
 312
 313       if ((memcached_io_writev(instance, vector, 4, false)) == false)
 314       {
 315         failures_occured_in_sending= true;
 316         continue;
 317       }
 318       WATCHPOINT_ASSERT(instance->cursor_active == 0);
 319       memcached_server_response_increment(instance);
 320       WATCHPOINT_ASSERT(instance->cursor_active == 1);
 321     }
 322     else
 323     {
 324       if ((memcached_io_writev(instance, (vector + 1), 3, false)) == false)
 325       {
 326         memcached_server_response_reset(instance);
 327         failures_occured_in_sending= true;
 328         continue;
 329       }
 330     }
 331   }
 332
 333   if (hosts_connected == 0)
 334   {
 335     LIBMEMCACHED_MEMCACHED_MGET_END();
 336
 337     if (memcached_failed(rc))
 338     {
 339       return rc;
 340     }
 341
 342     return memcached_set_error(*ptr, MEMCACHED_NO_SERVERS, MEMCACHED_AT);
 343   }
 344
 345
 346   /*
 347     Should we muddle on if some servers are dead?
 348   */
 349   bool success_happened= false;
 350   for (uint32_t x= 0; x < memcached_server_count(ptr); x++)
 351   {
 352     memcached_server_write_instance_st instance=
 353       memcached_server_instance_fetch(ptr, x);
 354
 355     if (memcached_server_response_count(instance))
 356     {
 357       /* We need to do something about non-connnected hosts in the future */
 358       if ((memcached_io_write(instance, "\r\n", 2, true)) == -1)
 359       {
 360         failures_occured_in_sending= true;
 361       }
 362       else
 363       {
 364         success_happened= true;
 365       }
 366     }
 367   }
 368
 369   LIBMEMCACHED_MEMCACHED_MGET_END();
 370
 371   if (failures_occured_in_sending and success_happened)
 372   {
 373     return MEMCACHED_SOME_ERRORS;
 374   }
 375
 376   if (success_happened)
 377   {
 378     return MEMCACHED_SUCCESS;
 379   }
 380
 381   return MEMCACHED_FAILURE; // Complete failure occurred
 382 }
 383
 384 memcached_return_t memcached_mget_by_key(memcached_st *ptr,
 385                                          const char *group_key,
 386                                          size_t group_key_length,
 387                                          const char * const *keys,
 388                                          const size_t *key_length,
 389                                          size_t number_of_keys)
 390 {
 391   return memcached_mget_by_key_real(ptr, group_key, group_key_length, keys,
 392                                     key_length, number_of_keys, true);
 393 }
 394
 395 memcached_return_t memcached_mget_execute(memcached_st *ptr,
 396                                           const char * const *keys,
 397                                           const size_t *key_length,
 398                                           size_t number_of_keys,
 399                                           memcached_execute_fn *callback,
 400                                           void *context,
 401                                           unsigned int number_of_callbacks)
 402 {
 403   return memcached_mget_execute_by_key(ptr, NULL, 0, keys, key_length,
 404                                        number_of_keys, callback,
 405                                        context, number_of_callbacks);
 406 }
 407
 408 memcached_return_t memcached_mget_execute_by_key(memcached_st *ptr,
 409                                                  const char *group_key,
 410                                                  size_t group_key_length,
 411                                                  const char * const *keys,
 412                                                  const size_t *key_length,
 413                                                  size_t number_of_keys,
 414                                                  memcached_execute_fn *callback,
 415                                                  void *context,
 416                                                  unsigned int number_of_callbacks)
 417 {
 418   memcached_return_t rc;
 419   if (memcached_failed(rc= initialize_query(ptr, false)))
 420   {
 421     return rc;
 422   }
 423
 424   if (memcached_is_udp(ptr))
 425   {
 426     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT);
 427   }
 428
 429   if (memcached_is_binary(ptr) == false)
 430   {
 431     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT,
 432                                memcached_literal_param("ASCII protocol is not supported for memcached_mget_execute_by_key()"));
 433   }
 434
 435   memcached_callback_st *original_callbacks= ptr->callbacks;
 436   memcached_callback_st cb= {
 437     callback,
 438     context,
 439     number_of_callbacks
 440   };
 441
 442   ptr->callbacks= &cb;
 443   rc= memcached_mget_by_key(ptr, group_key, group_key_length, keys,
 444                             key_length, number_of_keys);
 445   ptr->callbacks= original_callbacks;
 446   return rc;
 447 }
 448
 449 static memcached_return_t simple_binary_mget(memcached_st *ptr,
 450                                              uint32_t master_server_key,
 451                                              bool is_group_key_set,
 452                                              const char * const *keys,
 453                                              const size_t *key_length,
 454                                              size_t number_of_keys, bool mget_mode)
 455 {
 456   memcached_return_t rc= MEMCACHED_NOTFOUND;
 457
 458   bool flush= (number_of_keys == 1);
 459
 460   /*
 461     If a server fails we warn about errors and start all over with sending keys
 462     to the server.
 463   */
 464   for (uint32_t x= 0; x < number_of_keys; ++x)
 465   {
 466     uint32_t server_key;
 467
 468     if (is_group_key_set)
 469     {
 470       server_key= master_server_key;
 471     }
 472     else
 473     {
 474       server_key= memcached_generate_hash_with_redistribution(ptr, keys[x], key_length[x]);
 475     }
 476
 477     memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, server_key);
 478
 479     if (memcached_server_response_count(instance) == 0)
 480     {
 481       rc= memcached_connect(instance);
 482       if (memcached_failed(rc))
 483       {
 484         continue;
 485       }
 486     }
 487
 488     protocol_binary_request_getk request= { }; //= {.bytes= {0}};
 489     request.message.header.request.magic= PROTOCOL_BINARY_REQ;
 490     if (mget_mode)
 491     {
 492       request.message.header.request.opcode= PROTOCOL_BINARY_CMD_GETKQ;
 493     }
 494     else
 495     {
 496       request.message.header.request.opcode= PROTOCOL_BINARY_CMD_GETK;
 497     }
 498
 499     memcached_return_t vk;
 500     vk= memcached_validate_key_length(key_length[x],
 501                                       ptr->flags.binary_protocol);
 502     if (vk != MEMCACHED_SUCCESS)
 503     {
 504       if (x > 0)
 505       {
 506         memcached_io_reset(instance);
 507       }
 508
 509       return vk;
 510     }
 511
 512     request.message.header.request.keylen= htons((uint16_t)(key_length[x] + memcached_array_size(ptr->_namespace)));
 513     request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 514     request.message.header.request.bodylen= htonl((uint32_t)( key_length[x] + memcached_array_size(ptr->_namespace)));
 515
 516     libmemcached_io_vector_st vector[]=
 517     {
 518       { request.bytes, sizeof(request.bytes) },
 519       { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 520       { keys[x], key_length[x] }
 521     };
 522
 523     if (memcached_io_writev(instance, vector, 3, flush) == false)
 524     {
 525       memcached_server_response_reset(instance);
 526       rc= MEMCACHED_SOME_ERRORS;
 527       continue;
 528     }
 529
 530     /* We just want one pending response per server */
 531     memcached_server_response_reset(instance);
 532     memcached_server_response_increment(instance);
 533     if ((x > 0 and x == ptr->io_key_prefetch) and memcached_flush_buffers(ptr) != MEMCACHED_SUCCESS)
 534     {
 535       rc= MEMCACHED_SOME_ERRORS;
 536     }
 537   }
 538
 539   if (mget_mode)
 540   {
 541     /*
 542       Send a noop command to flush the buffers
 543     */
 544     protocol_binary_request_noop request= {}; //= {.bytes= {0}};
 545     request.message.header.request.magic= PROTOCOL_BINARY_REQ;
 546     request.message.header.request.opcode= PROTOCOL_BINARY_CMD_NOOP;
 547     request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 548
 549     for (uint32_t x= 0; x < memcached_server_count(ptr); ++x)
 550     {
 551       memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, x);
 552
 553       if (memcached_server_response_count(instance))
 554       {
 555         if (memcached_io_write(instance) == false)
 556         {
 557           memcached_server_response_reset(instance);
 558           memcached_io_reset(instance);
 559           rc= MEMCACHED_SOME_ERRORS;
 560         }
 561
 562         if (memcached_io_write(instance, request.bytes,
 563                                sizeof(request.bytes), true) == -1)
 564         {
 565           memcached_server_response_reset(instance);
 566           memcached_io_reset(instance);
 567           rc= MEMCACHED_SOME_ERRORS;
 568         }
 569       }
 570     }
 571   }
 572
 573
 574   return rc;
 575 }
 576
 577 static memcached_return_t replication_binary_mget(memcached_st *ptr,
 578                                                   uint32_t* hash,
 579                                                   bool* dead_servers,
 580                                                   const char *const *keys,
 581                                                   const size_t *key_length,
 582                                                   size_t number_of_keys)
 583 {
 584   memcached_return_t rc= MEMCACHED_NOTFOUND;
 585   uint32_t start= 0;
 586   uint64_t randomize_read= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ);
 587
 588   if (randomize_read)
 589   {
 590     start= (uint32_t)random() % (uint32_t)(ptr->number_of_replicas + 1);
 591   }
 592
 593   /* Loop for each replica */
 594   for (uint32_t replica= 0; replica <= ptr->number_of_replicas; ++replica)
 595   {
 596     bool success= true;
 597
 598     for (uint32_t x= 0; x < number_of_keys; ++x)
 599     {
 600       if (hash[x] == memcached_server_count(ptr))
 601         continue; /* Already successfully sent */
 602
 603       uint32_t server= hash[x] + replica;
 604
 605       /* In case of randomized reads */
 606       if (randomize_read and ((server + start) <= (hash[x] + ptr->number_of_replicas)))
 607       {
 608         server+= start;
 609       }
 610
 611       while (server >= memcached_server_count(ptr))
 612       {
 613         server -= memcached_server_count(ptr);
 614       }
 615
 616       if (dead_servers[server])
 617       {
 618         continue;
 619       }
 620
 621       memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, server);
 622
 623       if (memcached_server_response_count(instance) == 0)
 624       {
 625         rc= memcached_connect(instance);
 626
 627         if (memcached_failed(rc))
 628         {
 629           memcached_io_reset(instance);
 630           dead_servers[server]= true;
 631           success= false;
 632           continue;
 633         }
 634       }
 635
 636       protocol_binary_request_getk request= {};
 637       request.message.header.request.magic= PROTOCOL_BINARY_REQ;
 638       request.message.header.request.opcode= PROTOCOL_BINARY_CMD_GETK;
 639       request.message.header.request.keylen= htons((uint16_t)(key_length[x] + memcached_array_size(ptr->_namespace)));
 640       request.message.header.request.datatype= PROTOCOL_BINARY_RAW_BYTES;
 641       request.message.header.request.bodylen= htonl((uint32_t)(key_length[x] + memcached_array_size(ptr->_namespace)));
 642
 643       /*
 644        * We need to disable buffering to actually know that the request was
 645        * successfully sent to the server (so that we should expect a result
 646        * back). It would be nice to do this in buffered mode, but then it
 647        * would be complex to handle all error situations if we got to send
 648        * some of the messages, and then we failed on writing out some others
 649        * and we used the callback interface from memcached_mget_execute so
 650        * that we might have processed some of the responses etc. For now,
 651        * just make sure we work _correctly_
 652      */
 653       libmemcached_io_vector_st vector[]=
 654       {
 655         { request.bytes, sizeof(request.bytes) },
 656         { memcached_array_string(ptr->_namespace), memcached_array_size(ptr->_namespace) },
 657         { keys[x], key_length[x] }
 658       };
 659
 660       if (memcached_io_writev(instance, vector, 3, true) == false)
 661       {
 662         memcached_io_reset(instance);
 663         dead_servers[server]= true;
 664         success= false;
 665         continue;
 666       }
 667
 668       memcached_server_response_increment(instance);
 669       hash[x]= memcached_server_count(ptr);
 670     }
 671
 672     if (success)
 673     {
 674       break;
 675     }
 676   }
 677
 678   return rc;
 679 }
 680
 681 static memcached_return_t binary_mget_by_key(memcached_st *ptr,
 682                                              uint32_t master_server_key,
 683                                              bool is_group_key_set,
 684                                              const char * const *keys,
 685                                              const size_t *key_length,
 686                                              size_t number_of_keys,
 687                                              bool mget_mode)
 688 {
 689   if (ptr->number_of_replicas == 0)
 690   {
 691     return simple_binary_mget(ptr, master_server_key, is_group_key_set,
 692                               keys, key_length, number_of_keys, mget_mode);
 693   }
 694
 695   uint32_t* hash= libmemcached_xvalloc(ptr, number_of_keys, uint32_t);
 696   bool* dead_servers= libmemcached_xcalloc(ptr, memcached_server_count(ptr), bool);
 697
 698   if (hash == NULL or dead_servers == NULL)
 699   {
 700     libmemcached_free(ptr, hash);
 701     libmemcached_free(ptr, dead_servers);
 702     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 703   }
 704
 705   if (is_group_key_set)
 706   {
 707     for (size_t x= 0; x < number_of_keys; x++)
 708     {
 709       hash[x]= master_server_key;
 710     }
 711   }
 712   else
 713   {
 714     for (size_t x= 0; x < number_of_keys; x++)
 715     {
 716       hash[x]= memcached_generate_hash_with_redistribution(ptr, keys[x], key_length[x]);
 717     }
 718   }
 719
 720   memcached_return_t rc= replication_binary_mget(ptr, hash, dead_servers, keys,
 721                                                  key_length, number_of_keys);
 722
 723   WATCHPOINT_IFERROR(rc);
 724   libmemcached_free(ptr, hash);
 725   libmemcached_free(ptr, dead_servers);
 726
 727   return MEMCACHED_SUCCESS;
 728 }