2 * Copyright (C) 2006-2009 Brian Aker
5 * Use and distribution licensed under the BSD license. See
6 * the COPYING file in the parent directory for full text.
8 * Summary: Get functions for libmemcached
15 What happens if no servers exist?
17 char *memcached_get(memcached_st
*ptr
, const char *key
,
21 memcached_return_t
*error
)
23 return memcached_get_by_key(ptr
, NULL
, 0, key
, key_length
, value_length
,
27 static memcached_return_t
memcached_mget_by_key_real(memcached_st
*ptr
,
28 const char *master_key
,
29 size_t master_key_length
,
30 const char * const *keys
,
31 const size_t *key_length
,
32 size_t number_of_keys
,
35 char *memcached_get_by_key(memcached_st
*ptr
,
36 const char *master_key
,
37 size_t master_key_length
,
38 const char *key
, size_t key_length
,
41 memcached_return_t
*error
)
46 memcached_return_t dummy_error
;
48 unlikely (ptr
->flags
.use_udp
)
50 *error
= MEMCACHED_NOT_SUPPORTED
;
55 *error
= memcached_mget_by_key_real(ptr
, master_key
, master_key_length
,
56 (const char * const *)&key
,
57 &key_length
, 1, false);
59 value
= memcached_fetch(ptr
, NULL
, NULL
,
60 value_length
, flags
, error
);
61 /* This is for historical reasons */
62 if (*error
== MEMCACHED_END
)
63 *error
= MEMCACHED_NOTFOUND
;
67 if (ptr
->get_key_failure
&& *error
== MEMCACHED_NOTFOUND
)
69 memcached_return_t rc
;
71 memcached_result_reset(&ptr
->result
);
72 rc
= ptr
->get_key_failure(ptr
, key
, key_length
, &ptr
->result
);
74 /* On all failure drop to returning NULL */
75 if (rc
== MEMCACHED_SUCCESS
|| rc
== MEMCACHED_BUFFERED
)
77 if (rc
== MEMCACHED_BUFFERED
)
79 uint64_t latch
; /* We use latch to track the state of the original socket */
80 latch
= memcached_behavior_get(ptr
, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
);
82 memcached_behavior_set(ptr
, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
, 1);
84 rc
= memcached_set(ptr
, key
, key_length
,
85 (memcached_result_value(&ptr
->result
)),
86 (memcached_result_length(&ptr
->result
)),
88 (memcached_result_flags(&ptr
->result
)));
90 if (rc
== MEMCACHED_BUFFERED
&& latch
== 0)
91 memcached_behavior_set(ptr
, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
, 0);
95 rc
= memcached_set(ptr
, key
, key_length
,
96 (memcached_result_value(&ptr
->result
)),
97 (memcached_result_length(&ptr
->result
)),
99 (memcached_result_flags(&ptr
->result
)));
102 if (rc
== MEMCACHED_SUCCESS
|| rc
== MEMCACHED_BUFFERED
)
105 *value_length
= memcached_result_length(&ptr
->result
);
106 *flags
= memcached_result_flags(&ptr
->result
);
107 return memcached_string_c_copy(&ptr
->result
.value
);
115 (void)memcached_fetch(ptr
, NULL
, NULL
,
116 &dummy_length
, &dummy_flags
,
118 WATCHPOINT_ASSERT(dummy_length
== 0);
123 memcached_return_t
memcached_mget(memcached_st
*ptr
,
124 const char * const *keys
,
125 const size_t *key_length
,
126 size_t number_of_keys
)
128 return memcached_mget_by_key(ptr
, NULL
, 0, keys
, key_length
, number_of_keys
);
131 static memcached_return_t
binary_mget_by_key(memcached_st
*ptr
,
132 uint32_t master_server_key
,
133 bool is_master_key_set
,
134 const char * const *keys
,
135 const size_t *key_length
,
136 size_t number_of_keys
,
139 static memcached_return_t
memcached_mget_by_key_real(memcached_st
*ptr
,
140 const char *master_key
,
141 size_t master_key_length
,
142 const char * const *keys
,
143 const size_t *key_length
,
144 size_t number_of_keys
,
147 bool failures_occured_in_sending
= false;
148 const char *get_command
= "get ";
149 uint8_t get_command_length
= 4;
150 unsigned int master_server_key
= (unsigned int)-1; /* 0 is a valid server id! */
151 bool is_master_key_set
= false;
153 memcached_return_t rc
;
154 if ((rc
= initialize_query(ptr
)) != MEMCACHED_SUCCESS
)
159 unlikely (ptr
->flags
.use_udp
)
160 return MEMCACHED_NOT_SUPPORTED
;
162 LIBMEMCACHED_MEMCACHED_MGET_START();
164 if (number_of_keys
== 0)
165 return MEMCACHED_NOTFOUND
;
167 if (ptr
->flags
.verify_key
&& (memcached_key_test(keys
, key_length
, number_of_keys
) == MEMCACHED_BAD_KEY_PROVIDED
))
168 return MEMCACHED_BAD_KEY_PROVIDED
;
170 if (master_key
&& master_key_length
)
172 if (ptr
->flags
.verify_key
&& (memcached_key_test((const char * const *)&master_key
, &master_key_length
, 1) == MEMCACHED_BAD_KEY_PROVIDED
))
173 return MEMCACHED_BAD_KEY_PROVIDED
;
174 master_server_key
= memcached_generate_hash_with_redistribution(ptr
, master_key
, master_key_length
);
175 is_master_key_set
= true;
179 Here is where we pay for the non-block API. We need to remove any data sitting
180 in the queue before we start our get.
182 It might be optimum to bounce the connection if count > some number.
184 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++)
186 memcached_server_write_instance_st instance
=
187 memcached_server_instance_fetch(ptr
, x
);
189 if (memcached_server_response_count(instance
))
191 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
193 if (ptr
->flags
.no_block
)
194 (void)memcached_io_write(instance
, NULL
, 0, true);
196 while(memcached_server_response_count(instance
))
197 (void)memcached_response(instance
, buffer
, MEMCACHED_DEFAULT_COMMAND_SIZE
, &ptr
->result
);
201 if (ptr
->flags
.binary_protocol
)
203 return binary_mget_by_key(ptr
, master_server_key
, is_master_key_set
, keys
,
204 key_length
, number_of_keys
, mget_mode
);
207 if (ptr
->flags
.support_cas
)
209 get_command
= "gets ";
210 get_command_length
= 5;
214 If a server fails we warn about errors and start all over with sending keys
217 WATCHPOINT_ASSERT(rc
== MEMCACHED_SUCCESS
);
218 size_t hosts_connected
= 0;
219 for (uint32_t x
= 0; x
< number_of_keys
; x
++)
221 memcached_server_write_instance_st instance
;
224 if (is_master_key_set
)
226 server_key
= master_server_key
;
230 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
233 instance
= memcached_server_instance_fetch(ptr
, server_key
);
235 struct libmemcached_io_vector_st vector
[]=
237 { .length
= get_command_length
, .buffer
= get_command
},
238 { .length
= memcached_array_size(ptr
->prefix_key
), .buffer
= memcached_array_string(ptr
->prefix_key
) },
239 { .length
= key_length
[x
], .buffer
= keys
[x
] },
240 { .length
= 1, .buffer
= " " }
244 if (memcached_server_response_count(instance
) == 0)
246 rc
= memcached_connect(instance
);
248 if (rc
!= MEMCACHED_SUCCESS
)
254 if ((memcached_io_writev(instance
, vector
, 4, false)) == -1)
256 failures_occured_in_sending
= true;
259 WATCHPOINT_ASSERT(instance
->cursor_active
== 0);
260 memcached_server_response_increment(instance
);
261 WATCHPOINT_ASSERT(instance
->cursor_active
== 1);
265 if ((memcached_io_writev(instance
, (vector
+ 1), 3, false)) == -1)
267 memcached_server_response_reset(instance
);
268 failures_occured_in_sending
= true;
274 if (hosts_connected
== 0)
276 LIBMEMCACHED_MEMCACHED_MGET_END();
278 if (rc
!= MEMCACHED_SUCCESS
)
281 return MEMCACHED_NO_SERVERS
;
286 Should we muddle on if some servers are dead?
288 bool success_happened
= false;
289 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++)
291 memcached_server_write_instance_st instance
=
292 memcached_server_instance_fetch(ptr
, x
);
294 if (memcached_server_response_count(instance
))
296 /* We need to do something about non-connnected hosts in the future */
297 if ((memcached_io_write(instance
, "\r\n", 2, true)) == -1)
299 failures_occured_in_sending
= true;
303 success_happened
= true;
308 LIBMEMCACHED_MEMCACHED_MGET_END();
310 if (failures_occured_in_sending
&& success_happened
)
311 return MEMCACHED_SOME_ERRORS
;
313 if (success_happened
)
314 return MEMCACHED_SUCCESS
;
316 return MEMCACHED_FAILURE
;
319 memcached_return_t
memcached_mget_by_key(memcached_st
*ptr
,
320 const char *master_key
,
321 size_t master_key_length
,
322 const char * const *keys
,
323 const size_t *key_length
,
324 size_t number_of_keys
)
326 return memcached_mget_by_key_real(ptr
, master_key
, master_key_length
, keys
,
327 key_length
, number_of_keys
, true);
330 memcached_return_t
memcached_mget_execute(memcached_st
*ptr
,
331 const char * const *keys
,
332 const size_t *key_length
,
333 size_t number_of_keys
,
334 memcached_execute_fn
*callback
,
336 unsigned int number_of_callbacks
)
338 return memcached_mget_execute_by_key(ptr
, NULL
, 0, keys
, key_length
,
339 number_of_keys
, callback
,
340 context
, number_of_callbacks
);
343 memcached_return_t
memcached_mget_execute_by_key(memcached_st
*ptr
,
344 const char *master_key
,
345 size_t master_key_length
,
346 const char * const *keys
,
347 const size_t *key_length
,
348 size_t number_of_keys
,
349 memcached_execute_fn
*callback
,
351 unsigned int number_of_callbacks
)
353 if ((ptr
->flags
.binary_protocol
) == 0)
354 return MEMCACHED_NOT_SUPPORTED
;
356 memcached_return_t rc
;
357 memcached_callback_st
*original_callbacks
= ptr
->callbacks
;
358 memcached_callback_st cb
= {
361 .number_of_callback
= number_of_callbacks
365 rc
= memcached_mget_by_key(ptr
, master_key
, master_key_length
, keys
,
366 key_length
, number_of_keys
);
367 ptr
->callbacks
= original_callbacks
;
371 static memcached_return_t
simple_binary_mget(memcached_st
*ptr
,
372 uint32_t master_server_key
,
373 bool is_master_key_set
,
374 const char * const *keys
,
375 const size_t *key_length
,
376 size_t number_of_keys
, bool mget_mode
)
378 memcached_return_t rc
= MEMCACHED_NOTFOUND
;
380 bool flush
= (number_of_keys
== 1);
383 If a server fails we warn about errors and start all over with sending keys
386 for (uint32_t x
= 0; x
< number_of_keys
; ++x
)
389 memcached_server_write_instance_st instance
;
391 if (is_master_key_set
)
393 server_key
= master_server_key
;
397 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
400 instance
= memcached_server_instance_fetch(ptr
, server_key
);
402 if (memcached_server_response_count(instance
) == 0)
404 rc
= memcached_connect(instance
);
405 if (rc
!= MEMCACHED_SUCCESS
)
409 protocol_binary_request_getk request
= {.bytes
= {0}};
410 request
.message
.header
.request
.magic
= PROTOCOL_BINARY_REQ
;
412 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETKQ
;
414 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETK
;
416 memcached_return_t vk
;
417 vk
= memcached_validate_key_length(key_length
[x
],
418 ptr
->flags
.binary_protocol
);
419 unlikely (vk
!= MEMCACHED_SUCCESS
)
423 memcached_io_reset(instance
);
429 request
.message
.header
.request
.keylen
= htons((uint16_t)(key_length
[x
] + memcached_array_size(ptr
->prefix_key
)));
430 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
431 request
.message
.header
.request
.bodylen
= htonl((uint32_t)( key_length
[x
] + memcached_array_size(ptr
->prefix_key
)));
433 struct libmemcached_io_vector_st vector
[]=
435 { .length
= sizeof(request
.bytes
), .buffer
= request
.bytes
},
436 { .length
= memcached_array_size(ptr
->prefix_key
), .buffer
= memcached_array_string(ptr
->prefix_key
) },
437 { .length
= key_length
[x
], .buffer
= keys
[x
] }
440 if (memcached_io_writev(instance
, vector
, 3, flush
) == -1)
442 memcached_server_response_reset(instance
);
443 rc
= MEMCACHED_SOME_ERRORS
;
447 /* We just want one pending response per server */
448 memcached_server_response_reset(instance
);
449 memcached_server_response_increment(instance
);
450 if ((x
> 0 && x
== ptr
->io_key_prefetch
) && memcached_flush_buffers(ptr
) != MEMCACHED_SUCCESS
)
452 rc
= MEMCACHED_SOME_ERRORS
;
459 * Send a noop command to flush the buffers
461 protocol_binary_request_noop request
= {.bytes
= {0}};
462 request
.message
.header
.request
.magic
= PROTOCOL_BINARY_REQ
;
463 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_NOOP
;
464 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
466 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); ++x
)
468 memcached_server_write_instance_st instance
=
469 memcached_server_instance_fetch(ptr
, x
);
471 if (memcached_server_response_count(instance
))
473 if (memcached_io_write(instance
, NULL
, 0, true) == -1)
475 memcached_server_response_reset(instance
);
476 memcached_io_reset(instance
);
477 rc
= MEMCACHED_SOME_ERRORS
;
480 if (memcached_io_write(instance
, request
.bytes
,
481 sizeof(request
.bytes
), true) == -1)
483 memcached_server_response_reset(instance
);
484 memcached_io_reset(instance
);
485 rc
= MEMCACHED_SOME_ERRORS
;
495 static memcached_return_t
replication_binary_mget(memcached_st
*ptr
,
498 const char *const *keys
,
499 const size_t *key_length
,
500 size_t number_of_keys
)
502 memcached_return_t rc
= MEMCACHED_NOTFOUND
;
504 uint64_t randomize_read
= memcached_behavior_get(ptr
, MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ
);
507 start
= (uint32_t)random() % (uint32_t)(ptr
->number_of_replicas
+ 1);
509 /* Loop for each replica */
510 for (uint32_t replica
= 0; replica
<= ptr
->number_of_replicas
; ++replica
)
514 for (uint32_t x
= 0; x
< number_of_keys
; ++x
)
516 memcached_server_write_instance_st instance
;
518 if (hash
[x
] == memcached_server_count(ptr
))
519 continue; /* Already successfully sent */
521 uint32_t server
= hash
[x
] + replica
;
523 /* In case of randomized reads */
524 if (randomize_read
&& ((server
+ start
) <= (hash
[x
] + ptr
->number_of_replicas
)))
527 while (server
>= memcached_server_count(ptr
))
528 server
-= memcached_server_count(ptr
);
530 if (dead_servers
[server
])
533 instance
= memcached_server_instance_fetch(ptr
, server
);
535 if (memcached_server_response_count(instance
) == 0)
537 rc
= memcached_connect(instance
);
538 if (rc
!= MEMCACHED_SUCCESS
)
540 memcached_io_reset(instance
);
541 dead_servers
[server
]= true;
547 protocol_binary_request_getk request
= {
548 .message
.header
.request
= {
549 .magic
= PROTOCOL_BINARY_REQ
,
550 .opcode
= PROTOCOL_BINARY_CMD_GETK
,
551 .keylen
= htons((uint16_t)(key_length
[x
] + memcached_array_size(ptr
->prefix_key
))),
552 .datatype
= PROTOCOL_BINARY_RAW_BYTES
,
553 .bodylen
= htonl((uint32_t)(key_length
[x
] + memcached_array_size(ptr
->prefix_key
)))
558 * We need to disable buffering to actually know that the request was
559 * successfully sent to the server (so that we should expect a result
560 * back). It would be nice to do this in buffered mode, but then it
561 * would be complex to handle all error situations if we got to send
562 * some of the messages, and then we failed on writing out some others
563 * and we used the callback interface from memcached_mget_execute so
564 * that we might have processed some of the responses etc. For now,
565 * just make sure we work _correctly_
567 struct libmemcached_io_vector_st vector
[]=
569 { .length
= sizeof(request
.bytes
), .buffer
= request
.bytes
},
570 { .length
= memcached_array_size(ptr
->prefix_key
), .buffer
= memcached_array_string(ptr
->prefix_key
) },
571 { .length
= key_length
[x
], .buffer
= keys
[x
] }
574 if (memcached_io_writev(instance
, vector
, 3, true) == -1)
576 memcached_io_reset(instance
);
577 dead_servers
[server
]= true;
582 memcached_server_response_increment(instance
);
583 hash
[x
]= memcached_server_count(ptr
);
593 static memcached_return_t
binary_mget_by_key(memcached_st
*ptr
,
594 uint32_t master_server_key
,
595 bool is_master_key_set
,
596 const char * const *keys
,
597 const size_t *key_length
,
598 size_t number_of_keys
,
601 memcached_return_t rc
;
603 if (ptr
->number_of_replicas
== 0)
605 rc
= simple_binary_mget(ptr
, master_server_key
, is_master_key_set
,
606 keys
, key_length
, number_of_keys
, mget_mode
);
613 hash
= libmemcached_malloc(ptr
, sizeof(uint32_t) * number_of_keys
);
614 dead_servers
= libmemcached_calloc(ptr
, memcached_server_count(ptr
), sizeof(bool));
616 if (hash
== NULL
|| dead_servers
== NULL
)
618 libmemcached_free(ptr
, hash
);
619 libmemcached_free(ptr
, dead_servers
);
620 return MEMCACHED_MEMORY_ALLOCATION_FAILURE
;
623 if (is_master_key_set
)
625 for (size_t x
= 0; x
< number_of_keys
; x
++)
627 hash
[x
]= master_server_key
;
632 for (size_t x
= 0; x
< number_of_keys
; x
++)
634 hash
[x
]= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
638 rc
= replication_binary_mget(ptr
, hash
, dead_servers
, keys
,
639 key_length
, number_of_keys
);
641 libmemcached_free(ptr
, hash
);
642 libmemcached_free(ptr
, dead_servers
);
644 return MEMCACHED_SUCCESS
;