git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/hosts.c

   1 /* LibMemcached
   2  * Copyright (C) 2006-2010 Brian Aker
   3  * All rights reserved.
   4  *
   5  * Use and distribution licensed under the BSD license.  See
   6  * the COPYING file in the parent directory for full text.
   7  *
   8  * Summary:
   9  *
  10  */
  11
  12 #include "common.h"
  13 #include <math.h>
  14
  15 /* Protoypes (static) */
  16 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
  17                                      in_port_t port,
  18                                      uint32_t weight,
  19                                      memcached_connection_t type);
  20
  21 static memcached_return_t update_continuum(memcached_st *ptr);
  22
  23 static int compare_servers(const void *p1, const void *p2)
  24 {
  25   int return_value;
  26   memcached_server_instance_st a= (memcached_server_instance_st)p1;
  27   memcached_server_instance_st b= (memcached_server_instance_st)p2;
  28
  29   return_value= strcmp(a->hostname, b->hostname);
  30
  31   if (return_value == 0)
  32   {
  33     return_value= (int) (a->port - b->port);
  34   }
  35
  36   return return_value;
  37 }
  38
  39 static void sort_hosts(memcached_st *ptr)
  40 {
  41   if (memcached_server_count(ptr))
  42   {
  43     memcached_server_write_instance_st instance;
  44
  45     qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
  46     instance= memcached_server_instance_fetch(ptr, 0);
  47     instance->number_of_hosts= memcached_server_count(ptr);
  48   }
  49 }
  50
  51
  52 memcached_return_t run_distribution(memcached_st *ptr)
  53 {
  54   if (ptr->flags.use_sort_hosts)
  55     sort_hosts(ptr);
  56
  57   switch (ptr->distribution)
  58   {
  59   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  60   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  61   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  62     return update_continuum(ptr);
  63   case MEMCACHED_DISTRIBUTION_MODULA:
  64     break;
  65   case MEMCACHED_DISTRIBUTION_RANDOM:
  66     srandom((uint32_t) time(NULL));
  67     break;
  68   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  69   default:
  70     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  71   }
  72
  73   return MEMCACHED_SUCCESS;
  74 }
  75
  76 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
  77 {
  78   unsigned char results[16];
  79
  80   libhashkit_md5_signature((unsigned char*)key, key_length, results);
  81
  82   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  83     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  84     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  85     | (results[0 + alignment * 4] & 0xFF);
  86 }
  87
  88 static int continuum_item_cmp(const void *t1, const void *t2)
  89 {
  90   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  91   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  92
  93   /* Why 153? Hmmm... */
  94   WATCHPOINT_ASSERT(ct1->value != 153);
  95   if (ct1->value == ct2->value)
  96     return EXIT_SUCCESS;
  97   else if (ct1->value > ct2->value)
  98     return EXIT_FAILURE;
  99   else
 100     return -1;
 101 }
 102
 103 static memcached_return_t update_continuum(memcached_st *ptr)
 104 {
 105   uint32_t host_index;
 106   uint32_t continuum_index= 0;
 107   uint32_t value;
 108   memcached_server_st *list;
 109   uint32_t pointer_index;
 110   uint32_t pointer_counter= 0;
 111   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 112   uint32_t pointer_per_hash= 1;
 113   uint64_t total_weight= 0;
 114   uint64_t is_ketama_weighted= 0;
 115   uint64_t is_auto_ejecting= 0;
 116   uint32_t points_per_server= 0;
 117   uint32_t live_servers= 0;
 118   struct timeval now;
 119
 120   if (gettimeofday(&now, NULL) != 0)
 121   {
 122     ptr->cached_errno = errno;
 123     return MEMCACHED_ERRNO;
 124   }
 125
 126   list = memcached_server_list(ptr);
 127
 128   /* count live servers (those without a retry delay set) */
 129   is_auto_ejecting= _is_auto_eject_host(ptr);
 130   if (is_auto_ejecting)
 131   {
 132     live_servers= 0;
 133     ptr->next_distribution_rebuild= 0;
 134     for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 135     {
 136       if (list[host_index].next_retry <= now.tv_sec)
 137         live_servers++;
 138       else
 139       {
 140         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 141           ptr->next_distribution_rebuild= list[host_index].next_retry;
 142       }
 143     }
 144   }
 145   else
 146   {
 147     live_servers= memcached_server_count(ptr);
 148   }
 149
 150   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 151   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 152
 153   if (live_servers == 0)
 154     return MEMCACHED_SUCCESS;
 155
 156   if (live_servers > ptr->continuum_count)
 157   {
 158     memcached_continuum_item_st *new_ptr;
 159
 160     new_ptr= libmemcached_realloc(ptr, ptr->continuum,
 161                                   sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 162
 163     if (new_ptr == 0)
 164       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 165
 166     ptr->continuum= new_ptr;
 167     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 168   }
 169
 170   if (is_ketama_weighted)
 171   {
 172     for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 173     {
 174       if (list[host_index].weight == 0)
 175       {
 176         list[host_index].weight = 1;
 177       }
 178       if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 179         total_weight += list[host_index].weight;
 180     }
 181   }
 182
 183   for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 184   {
 185     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 186       continue;
 187
 188     if (is_ketama_weighted)
 189     {
 190         float pct = (float)list[host_index].weight / (float)total_weight;
 191         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 192         pointer_per_hash= 4;
 193 #ifdef DEBUG
 194         printf("ketama_weighted:%s|%d|%llu|%u\n",
 195                list[host_index].hostname,
 196                list[host_index].port,
 197                (unsigned long long)list[host_index].weight,
 198                pointer_per_server);
 199 #endif
 200     }
 201
 202
 203     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 204     {
 205       for (pointer_index= 0;
 206            pointer_index < pointer_per_server / pointer_per_hash;
 207            pointer_index++)
 208       {
 209         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 210         int sort_host_length;
 211
 212         // Spymemcached ketema key format is: hostname/ip:port-index
 213         // If hostname is not available then: /ip:port-index
 214         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 215                                    "/%s:%u-%u",
 216                                    list[host_index].hostname,
 217                                    (uint32_t)list[host_index].port,
 218                                    pointer_index);
 219
 220         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 221         {
 222           return MEMCACHED_FAILURE;
 223         }
 224 #ifdef DEBUG
 225         printf("update_continuum: key is %s\n", sort_host);
 226 #endif
 227
 228         WATCHPOINT_ASSERT(sort_host_length);
 229
 230         if (is_ketama_weighted)
 231         {
 232           for (uint32_t x= 0; x < pointer_per_hash; x++)
 233           {
 234              value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 235              ptr->continuum[continuum_index].index= host_index;
 236              ptr->continuum[continuum_index++].value= value;
 237           }
 238         }
 239         else
 240         {
 241           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 242           ptr->continuum[continuum_index].index= host_index;
 243           ptr->continuum[continuum_index++].value= value;
 244         }
 245       }
 246     }
 247     else
 248     {
 249       for (pointer_index= 1;
 250            pointer_index <= pointer_per_server / pointer_per_hash;
 251            pointer_index++)
 252       {
 253         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 254         int sort_host_length;
 255
 256         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 257         {
 258           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 259                                      "%s-%u",
 260                                      list[host_index].hostname,
 261                                      pointer_index - 1);
 262         }
 263         else
 264         {
 265           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 266                                      "%s:%u-%u",
 267                                      list[host_index].hostname,
 268                                      (uint32_t)list[host_index].port,
 269                                      pointer_index - 1);
 270         }
 271
 272         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 273         {
 274           return MEMCACHED_FAILURE;
 275         }
 276
 277         WATCHPOINT_ASSERT(sort_host_length);
 278
 279         if (is_ketama_weighted)
 280         {
 281           for (uint32_t x = 0; x < pointer_per_hash; x++)
 282           {
 283              value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 284              ptr->continuum[continuum_index].index= host_index;
 285              ptr->continuum[continuum_index++].value= value;
 286           }
 287         }
 288         else
 289         {
 290           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 291           ptr->continuum[continuum_index].index= host_index;
 292           ptr->continuum[continuum_index++].value= value;
 293         }
 294       }
 295     }
 296
 297     pointer_counter+= pointer_per_server;
 298   }
 299
 300   WATCHPOINT_ASSERT(ptr);
 301   WATCHPOINT_ASSERT(ptr->continuum);
 302   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 303   ptr->continuum_points_counter= pointer_counter;
 304   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 305
 306 #ifdef DEBUG
 307   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 308   {
 309     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 310   }
 311 #endif
 312
 313   return MEMCACHED_SUCCESS;
 314 }
 315
 316
 317 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
 318 {
 319   uint32_t count;
 320   memcached_server_st *new_host_list;
 321
 322   if (! list)
 323     return MEMCACHED_SUCCESS;
 324
 325   count= memcached_server_list_count(list);
 326   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 327                                       sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
 328
 329   if (! new_host_list)
 330     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 331
 332   memcached_server_list_set(ptr, new_host_list);
 333
 334   for (uint32_t x= 0; x < count; x++)
 335   {
 336     memcached_server_write_instance_st instance;
 337
 338     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 339             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 340             && ! (ptr->flags.use_udp)) )
 341     {
 342       return MEMCACHED_INVALID_HOST_PROTOCOL;
 343     }
 344
 345     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 346
 347     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 348
 349     /* TODO check return type */
 350     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 351                                        list[x].port, list[x].weight, list[x].type);
 352     ptr->number_of_hosts++;
 353   }
 354
 355   // Provides backwards compatibility with server list.
 356   {
 357     memcached_server_write_instance_st instance;
 358     instance= memcached_server_instance_fetch(ptr, 0);
 359     instance->number_of_hosts= memcached_server_count(ptr);
 360   }
 361
 362   return run_distribution(ptr);
 363 }
 364
 365 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 366                                                     const char *filename)
 367 {
 368   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 369 }
 370
 371 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 372                                                                 const char *filename,
 373                                                                 uint32_t weight)
 374 {
 375   if (! filename)
 376     return MEMCACHED_FAILURE;
 377
 378   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 379 }
 380
 381 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 382                                             const char *hostname,
 383                                             in_port_t port)
 384 {
 385   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 386 }
 387
 388 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 389                                                         const char *hostname,
 390                                                         in_port_t port,
 391                                                         uint32_t weight)
 392 {
 393   if (! port)
 394     port= MEMCACHED_DEFAULT_PORT;
 395
 396   if (! hostname)
 397     hostname= "localhost";
 398
 399   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 400 }
 401
 402 memcached_return_t memcached_server_add(memcached_st *ptr,
 403                                         const char *hostname,
 404                                         in_port_t port)
 405 {
 406   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 407 }
 408
 409 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 410                                                     const char *hostname,
 411                                                     in_port_t port,
 412                                                     uint32_t weight)
 413 {
 414   if (! port)
 415     port= MEMCACHED_DEFAULT_PORT;
 416
 417   if (! hostname)
 418     hostname= "localhost";
 419
 420   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 421 }
 422
 423 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 424                                      in_port_t port,
 425                                      uint32_t weight,
 426                                      memcached_connection_t type)
 427 {
 428   memcached_server_st *new_host_list;
 429   memcached_server_write_instance_st instance;
 430
 431   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 432       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 433     return MEMCACHED_INVALID_HOST_PROTOCOL;
 434
 435   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 436                                       sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
 437
 438   if (new_host_list == NULL)
 439     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 440
 441   memcached_server_list_set(ptr, new_host_list);
 442
 443   /* TODO: Check return type */
 444   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 445   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 446   ptr->number_of_hosts++;
 447
 448   instance= memcached_server_instance_fetch(ptr, 0);
 449   memcached_servers_set_count(instance, memcached_server_count(ptr));
 450
 451   return run_distribution(ptr);
 452 }