Updating memcached_server_instance_st structure.
[m6w6/libmemcached] / 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 static memcached_return_t update_continuum(memcached_st *ptr);
21
22 static int compare_servers(const void *p1, const void *p2)
23 {
24 int return_value;
25 memcached_server_instance_st a= (memcached_server_instance_st)p1;
26 memcached_server_instance_st b= (memcached_server_instance_st)p2;
27
28 return_value= strcmp(a->hostname, b->hostname);
29
30 if (return_value == 0)
31 {
32 return_value= (int) (a->port - b->port);
33 }
34
35 return return_value;
36 }
37
38 static void sort_hosts(memcached_st *ptr)
39 {
40 if (memcached_server_count(ptr))
41 {
42 memcached_server_write_instance_st instance;
43
44 qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
45 instance= memcached_server_instance_fetch(ptr, 0);
46 instance->number_of_hosts= memcached_server_count(ptr);
47 }
48 }
49
50
51 memcached_return_t run_distribution(memcached_st *ptr)
52 {
53 if (ptr->flags.use_sort_hosts)
54 sort_hosts(ptr);
55
56 switch (ptr->distribution)
57 {
58 case MEMCACHED_DISTRIBUTION_CONSISTENT:
59 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
60 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
61 return update_continuum(ptr);
62 case MEMCACHED_DISTRIBUTION_MODULA:
63 break;
64 case MEMCACHED_DISTRIBUTION_RANDOM:
65 srandom((uint32_t) time(NULL));
66 break;
67 case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
68 default:
69 WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
70 }
71
72 ptr->last_disconnected_server = NULL;
73
74 return MEMCACHED_SUCCESS;
75 }
76
77 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
78 {
79 unsigned char results[16];
80
81 libhashkit_md5_signature((unsigned char*)key, key_length, results);
82
83 return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
84 | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
85 | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
86 | (results[0 + alignment * 4] & 0xFF);
87 }
88
89 static int continuum_item_cmp(const void *t1, const void *t2)
90 {
91 memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
92 memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
93
94 /* Why 153? Hmmm... */
95 WATCHPOINT_ASSERT(ct1->value != 153);
96 if (ct1->value == ct2->value)
97 return 0;
98 else if (ct1->value > ct2->value)
99 return 1;
100 else
101 return -1;
102 }
103
104 static memcached_return_t update_continuum(memcached_st *ptr)
105 {
106 uint32_t host_index;
107 uint32_t continuum_index= 0;
108 uint32_t value;
109 memcached_server_st *list;
110 uint32_t pointer_index;
111 uint32_t pointer_counter= 0;
112 uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
113 uint32_t pointer_per_hash= 1;
114 uint64_t total_weight= 0;
115 uint64_t is_ketama_weighted= 0;
116 uint64_t is_auto_ejecting= 0;
117 uint32_t points_per_server= 0;
118 uint32_t live_servers= 0;
119 struct timeval now;
120
121 if (gettimeofday(&now, NULL) != 0)
122 {
123 ptr->cached_errno = errno;
124 return MEMCACHED_ERRNO;
125 }
126
127 list = memcached_server_list(ptr);
128
129 /* count live servers (those without a retry delay set) */
130 is_auto_ejecting= _is_auto_eject_host(ptr);
131 if (is_auto_ejecting)
132 {
133 live_servers= 0;
134 ptr->next_distribution_rebuild= 0;
135 for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
136 {
137 if (list[host_index].next_retry <= now.tv_sec)
138 live_servers++;
139 else
140 {
141 if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
142 ptr->next_distribution_rebuild= list[host_index].next_retry;
143 }
144 }
145 }
146 else
147 {
148 live_servers= memcached_server_count(ptr);
149 }
150
151 is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
152 points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
153
154 if (live_servers == 0)
155 return MEMCACHED_SUCCESS;
156
157 if (live_servers > ptr->continuum_count)
158 {
159 memcached_continuum_item_st *new_ptr;
160
161 new_ptr= libmemcached_realloc(ptr, ptr->continuum,
162 sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
163
164 if (new_ptr == 0)
165 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
166
167 ptr->continuum= new_ptr;
168 ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
169 }
170
171 if (is_ketama_weighted)
172 {
173 for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
174 {
175 if (list[host_index].weight == 0)
176 {
177 list[host_index].weight = 1;
178 }
179 if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
180 total_weight += list[host_index].weight;
181 }
182 }
183
184 for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
185 {
186 if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
187 continue;
188
189 if (is_ketama_weighted)
190 {
191 float pct = (float)list[host_index].weight / (float)total_weight;
192 pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
193 pointer_per_hash= 4;
194 #ifdef DEBUG
195 printf("ketama_weighted:%s|%d|%llu|%u\n",
196 list[host_index].hostname,
197 list[host_index].port,
198 (unsigned long long)list[host_index].weight,
199 pointer_per_server);
200 #endif
201 }
202
203
204 if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
205 {
206 for (pointer_index= 0;
207 pointer_index < pointer_per_server / pointer_per_hash;
208 pointer_index++)
209 {
210 char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
211 size_t sort_host_length;
212
213 // Spymemcached ketema key format is: hostname/ip:port-index
214 // If hostname is not available then: /ip:port-index
215 sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
216 "/%s:%u-%u",
217 list[host_index].hostname,
218 (uint32_t)list[host_index].port,
219 pointer_index);
220 #ifdef DEBUG
221 printf("update_continuum: key is %s\n", sort_host);
222 #endif
223
224 WATCHPOINT_ASSERT(sort_host_length);
225
226 if (is_ketama_weighted)
227 {
228 for (uint32_t x= 0; x < pointer_per_hash; x++)
229 {
230 value= ketama_server_hash(sort_host, sort_host_length, x);
231 ptr->continuum[continuum_index].index= host_index;
232 ptr->continuum[continuum_index++].value= value;
233 }
234 }
235 else
236 {
237 value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
238 ptr->continuum[continuum_index].index= host_index;
239 ptr->continuum[continuum_index++].value= value;
240 }
241 }
242 }
243 else
244 {
245 for (pointer_index= 1;
246 pointer_index <= pointer_per_server / pointer_per_hash;
247 pointer_index++)
248 {
249 char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
250 size_t sort_host_length;
251
252 if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
253 {
254 sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
255 "%s-%u",
256 list[host_index].hostname,
257 pointer_index - 1);
258 }
259 else
260 {
261 sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
262 "%s:%u-%u",
263 list[host_index].hostname,
264 (uint32_t)list[host_index].port,
265 pointer_index - 1);
266 }
267
268 WATCHPOINT_ASSERT(sort_host_length);
269
270 if (is_ketama_weighted)
271 {
272 for (uint32_t x = 0; x < pointer_per_hash; x++)
273 {
274 value= ketama_server_hash(sort_host, sort_host_length, x);
275 ptr->continuum[continuum_index].index= host_index;
276 ptr->continuum[continuum_index++].value= value;
277 }
278 }
279 else
280 {
281 value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
282 ptr->continuum[continuum_index].index= host_index;
283 ptr->continuum[continuum_index++].value= value;
284 }
285 }
286 }
287
288 pointer_counter+= pointer_per_server;
289 }
290
291 WATCHPOINT_ASSERT(ptr);
292 WATCHPOINT_ASSERT(ptr->continuum);
293 WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
294 ptr->continuum_points_counter= pointer_counter;
295 qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
296
297 #ifdef DEBUG
298 for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
299 {
300 WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
301 }
302 #endif
303
304 return MEMCACHED_SUCCESS;
305 }
306
307
308 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_st *list)
309 {
310 uint32_t count;
311 memcached_server_st *new_host_list;
312
313 if (! list)
314 return MEMCACHED_SUCCESS;
315
316 count= memcached_server_list_count(list);
317 new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
318 sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
319
320 if (! new_host_list)
321 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
322
323 memcached_server_list_set(ptr, new_host_list);
324
325 for (uint32_t x= 0; x < count; x++)
326 {
327 memcached_server_write_instance_st instance;
328
329 if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
330 || ((list[x].type == MEMCACHED_CONNECTION_UDP)
331 && ! (ptr->flags.use_udp)) )
332 return MEMCACHED_INVALID_HOST_PROTOCOL;
333
334 WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
335
336 instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
337
338 /* TODO check return type */
339 (void)memcached_server_create_with(ptr, instance, list[x].hostname,
340 list[x].port, list[x].weight, list[x].type);
341 ptr->number_of_hosts++;
342 }
343
344 // Provides backwards compatibility with server list.
345 {
346 memcached_server_write_instance_st instance;
347 instance= memcached_server_instance_fetch(ptr, 0);
348 instance->number_of_hosts= memcached_server_count(ptr);
349 }
350
351 return run_distribution(ptr);
352 }
353
354 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
355 const char *filename)
356 {
357 return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
358 }
359
360 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
361 const char *filename,
362 uint32_t weight)
363 {
364 if (! filename)
365 return MEMCACHED_FAILURE;
366
367 return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
368 }
369
370 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
371 const char *hostname,
372 in_port_t port)
373 {
374 return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
375 }
376
377 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
378 const char *hostname,
379 in_port_t port,
380 uint32_t weight)
381 {
382 if (! port)
383 port= MEMCACHED_DEFAULT_PORT;
384
385 if (! hostname)
386 hostname= "localhost";
387
388 return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
389 }
390
391 memcached_return_t memcached_server_add(memcached_st *ptr,
392 const char *hostname,
393 in_port_t port)
394 {
395 return memcached_server_add_with_weight(ptr, hostname, port, 0);
396 }
397
398 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
399 const char *hostname,
400 in_port_t port,
401 uint32_t weight)
402 {
403 if (! port)
404 port= MEMCACHED_DEFAULT_PORT;
405
406 if (! hostname)
407 hostname= "localhost";
408
409 return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
410 }
411
412 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
413 in_port_t port,
414 uint32_t weight,
415 memcached_connection_t type)
416 {
417 memcached_server_st *new_host_list;
418 memcached_server_write_instance_st instance;
419
420 if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
421 || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
422 return MEMCACHED_INVALID_HOST_PROTOCOL;
423
424 new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
425 sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
426
427 if (new_host_list == NULL)
428 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
429
430 memcached_server_list_set(ptr, new_host_list);
431
432 /* TODO: Check return type */
433 instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
434 (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
435 ptr->number_of_hosts++;
436
437 instance= memcached_server_instance_fetch(ptr, 0);
438 memcached_servers_set_count(instance, memcached_server_count(ptr));
439
440 return run_distribution(ptr);
441 }