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 unlikely (ptr
->flags
.use_udp
)
154 return MEMCACHED_NOT_SUPPORTED
;
156 LIBMEMCACHED_MEMCACHED_MGET_START();
158 if (number_of_keys
== 0)
159 return MEMCACHED_NOTFOUND
;
161 if (memcached_server_count(ptr
) == 0)
162 return MEMCACHED_NO_SERVERS
;
164 if (ptr
->flags
.verify_key
&& (memcached_key_test(keys
, key_length
, number_of_keys
) == MEMCACHED_BAD_KEY_PROVIDED
))
165 return MEMCACHED_BAD_KEY_PROVIDED
;
167 if (master_key
&& master_key_length
)
169 if (ptr
->flags
.verify_key
&& (memcached_key_test((const char * const *)&master_key
, &master_key_length
, 1) == MEMCACHED_BAD_KEY_PROVIDED
))
170 return MEMCACHED_BAD_KEY_PROVIDED
;
171 master_server_key
= memcached_generate_hash_with_redistribution(ptr
, master_key
, master_key_length
);
172 is_master_key_set
= true;
176 Here is where we pay for the non-block API. We need to remove any data sitting
177 in the queue before we start our get.
179 It might be optimum to bounce the connection if count > some number.
181 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++)
183 memcached_server_write_instance_st instance
=
184 memcached_server_instance_fetch(ptr
, x
);
186 if (memcached_server_response_count(instance
))
188 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
190 if (ptr
->flags
.no_block
)
191 (void)memcached_io_write(instance
, NULL
, 0, true);
193 while(memcached_server_response_count(instance
))
194 (void)memcached_response(instance
, buffer
, MEMCACHED_DEFAULT_COMMAND_SIZE
, &ptr
->result
);
198 if (ptr
->flags
.binary_protocol
)
200 return binary_mget_by_key(ptr
, master_server_key
, is_master_key_set
, keys
,
201 key_length
, number_of_keys
, mget_mode
);
204 if (ptr
->flags
.support_cas
)
206 get_command
= "gets ";
207 get_command_length
= 5;
211 If a server fails we warn about errors and start all over with sending keys
214 memcached_return_t rc
= MEMCACHED_SUCCESS
;
215 size_t hosts_connected
= 0;
216 for (uint32_t x
= 0; x
< number_of_keys
; x
++)
218 memcached_server_write_instance_st instance
;
221 if (is_master_key_set
)
223 server_key
= master_server_key
;
227 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
230 instance
= memcached_server_instance_fetch(ptr
, server_key
);
232 struct libmemcached_io_vector_st vector
[]=
234 { .length
= get_command_length
, .buffer
= get_command
},
235 { .length
= ptr
->prefix_key_length
, .buffer
= ptr
->prefix_key
},
236 { .length
= key_length
[x
], .buffer
= keys
[x
] },
237 { .length
= 1, .buffer
= " " }
241 if (memcached_server_response_count(instance
) == 0)
243 rc
= memcached_connect(instance
);
245 if (rc
!= MEMCACHED_SUCCESS
)
251 if ((memcached_io_writev(instance
, vector
, 4, false)) == -1)
253 failures_occured_in_sending
= true;
256 WATCHPOINT_ASSERT(instance
->cursor_active
== 0);
257 memcached_server_response_increment(instance
);
258 WATCHPOINT_ASSERT(instance
->cursor_active
== 1);
262 if ((memcached_io_writev(instance
, (vector
+ 1), 3, false)) == -1)
264 memcached_server_response_reset(instance
);
265 failures_occured_in_sending
= true;
271 if (hosts_connected
== 0)
273 LIBMEMCACHED_MEMCACHED_MGET_END();
275 if (rc
!= MEMCACHED_SUCCESS
)
278 return MEMCACHED_NO_SERVERS
;
283 Should we muddle on if some servers are dead?
285 bool success_happened
= false;
286 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++)
288 memcached_server_write_instance_st instance
=
289 memcached_server_instance_fetch(ptr
, x
);
291 if (memcached_server_response_count(instance
))
293 /* We need to do something about non-connnected hosts in the future */
294 if ((memcached_io_write(instance
, "\r\n", 2, true)) == -1)
296 failures_occured_in_sending
= true;
300 success_happened
= true;
305 LIBMEMCACHED_MEMCACHED_MGET_END();
307 if (failures_occured_in_sending
&& success_happened
)
308 return MEMCACHED_SOME_ERRORS
;
310 if (success_happened
)
311 return MEMCACHED_SUCCESS
;
313 return MEMCACHED_FAILURE
;
316 memcached_return_t
memcached_mget_by_key(memcached_st
*ptr
,
317 const char *master_key
,
318 size_t master_key_length
,
319 const char * const *keys
,
320 const size_t *key_length
,
321 size_t number_of_keys
)
323 return memcached_mget_by_key_real(ptr
, master_key
, master_key_length
, keys
,
324 key_length
, number_of_keys
, true);
327 memcached_return_t
memcached_mget_execute(memcached_st
*ptr
,
328 const char * const *keys
,
329 const size_t *key_length
,
330 size_t number_of_keys
,
331 memcached_execute_fn
*callback
,
333 unsigned int number_of_callbacks
)
335 return memcached_mget_execute_by_key(ptr
, NULL
, 0, keys
, key_length
,
336 number_of_keys
, callback
,
337 context
, number_of_callbacks
);
340 memcached_return_t
memcached_mget_execute_by_key(memcached_st
*ptr
,
341 const char *master_key
,
342 size_t master_key_length
,
343 const char * const *keys
,
344 const size_t *key_length
,
345 size_t number_of_keys
,
346 memcached_execute_fn
*callback
,
348 unsigned int number_of_callbacks
)
350 if ((ptr
->flags
.binary_protocol
) == 0)
351 return MEMCACHED_NOT_SUPPORTED
;
353 memcached_return_t rc
;
354 memcached_callback_st
*original_callbacks
= ptr
->callbacks
;
355 memcached_callback_st cb
= {
358 .number_of_callback
= number_of_callbacks
362 rc
= memcached_mget_by_key(ptr
, master_key
, master_key_length
, keys
,
363 key_length
, number_of_keys
);
364 ptr
->callbacks
= original_callbacks
;
368 static memcached_return_t
simple_binary_mget(memcached_st
*ptr
,
369 uint32_t master_server_key
,
370 bool is_master_key_set
,
371 const char * const *keys
,
372 const size_t *key_length
,
373 size_t number_of_keys
, bool mget_mode
)
375 memcached_return_t rc
= MEMCACHED_NOTFOUND
;
377 int flush
= number_of_keys
== 1;
380 If a server fails we warn about errors and start all over with sending keys
383 for (uint32_t x
= 0; x
< number_of_keys
; ++x
)
386 memcached_server_write_instance_st instance
;
388 if (is_master_key_set
)
390 server_key
= master_server_key
;
394 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
397 instance
= memcached_server_instance_fetch(ptr
, server_key
);
399 if (memcached_server_response_count(instance
) == 0)
401 rc
= memcached_connect(instance
);
402 if (rc
!= MEMCACHED_SUCCESS
)
406 protocol_binary_request_getk request
= {.bytes
= {0}};
407 request
.message
.header
.request
.magic
= PROTOCOL_BINARY_REQ
;
409 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETKQ
;
411 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETK
;
413 memcached_return_t vk
;
414 vk
= memcached_validate_key_length(key_length
[x
],
415 ptr
->flags
.binary_protocol
);
416 unlikely (vk
!= MEMCACHED_SUCCESS
)
420 memcached_io_reset(instance
);
426 request
.message
.header
.request
.keylen
= htons((uint16_t)(key_length
[x
] + ptr
->prefix_key_length
));
427 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
428 request
.message
.header
.request
.bodylen
= htonl((uint32_t)( key_length
[x
] + ptr
->prefix_key_length
));
430 struct libmemcached_io_vector_st vector
[]=
432 { .length
= sizeof(request
.bytes
), .buffer
= request
.bytes
},
433 { .length
= ptr
->prefix_key_length
, .buffer
= ptr
->prefix_key
},
434 { .length
= key_length
[x
], .buffer
= keys
[x
] }
437 if (memcached_io_writev(instance
, vector
, 3, flush
) == -1)
439 memcached_server_response_reset(instance
);
440 rc
= MEMCACHED_SOME_ERRORS
;
444 /* We just want one pending response per server */
445 memcached_server_response_reset(instance
);
446 memcached_server_response_increment(instance
);
447 if ((x
> 0 && x
== ptr
->io_key_prefetch
) && memcached_flush_buffers(ptr
) != MEMCACHED_SUCCESS
)
449 rc
= MEMCACHED_SOME_ERRORS
;
456 * Send a noop command to flush the buffers
458 protocol_binary_request_noop request
= {.bytes
= {0}};
459 request
.message
.header
.request
.magic
= PROTOCOL_BINARY_REQ
;
460 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_NOOP
;
461 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
463 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); ++x
)
465 memcached_server_write_instance_st instance
=
466 memcached_server_instance_fetch(ptr
, x
);
468 if (memcached_server_response_count(instance
))
470 if (memcached_io_write(instance
, NULL
, 0, true) == -1)
472 memcached_server_response_reset(instance
);
473 memcached_io_reset(instance
);
474 rc
= MEMCACHED_SOME_ERRORS
;
477 if (memcached_io_write(instance
, request
.bytes
,
478 sizeof(request
.bytes
), true) == -1)
480 memcached_server_response_reset(instance
);
481 memcached_io_reset(instance
);
482 rc
= MEMCACHED_SOME_ERRORS
;
492 static memcached_return_t
replication_binary_mget(memcached_st
*ptr
,
495 const char *const *keys
,
496 const size_t *key_length
,
497 size_t number_of_keys
)
499 memcached_return_t rc
= MEMCACHED_NOTFOUND
;
501 uint64_t randomize_read
= memcached_behavior_get(ptr
, MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ
);
504 start
= (uint32_t)random() % (uint32_t)(ptr
->number_of_replicas
+ 1);
506 /* Loop for each replica */
507 for (uint32_t replica
= 0; replica
<= ptr
->number_of_replicas
; ++replica
)
511 for (uint32_t x
= 0; x
< number_of_keys
; ++x
)
513 memcached_server_write_instance_st instance
;
515 if (hash
[x
] == memcached_server_count(ptr
))
516 continue; /* Already successfully sent */
518 uint32_t server
= hash
[x
] + replica
;
520 /* In case of randomized reads */
521 if (randomize_read
&& ((server
+ start
) <= (hash
[x
] + ptr
->number_of_replicas
)))
524 while (server
>= memcached_server_count(ptr
))
525 server
-= memcached_server_count(ptr
);
527 if (dead_servers
[server
])
530 instance
= memcached_server_instance_fetch(ptr
, server
);
532 if (memcached_server_response_count(instance
) == 0)
534 rc
= memcached_connect(instance
);
535 if (rc
!= MEMCACHED_SUCCESS
)
537 memcached_io_reset(instance
);
538 dead_servers
[server
]= true;
544 protocol_binary_request_getk request
= {
545 .message
.header
.request
= {
546 .magic
= PROTOCOL_BINARY_REQ
,
547 .opcode
= PROTOCOL_BINARY_CMD_GETK
,
548 .keylen
= htons((uint16_t)(key_length
[x
] + ptr
->prefix_key_length
)),
549 .datatype
= PROTOCOL_BINARY_RAW_BYTES
,
550 .bodylen
= htonl((uint32_t)(key_length
[x
] + ptr
->prefix_key_length
))
555 * We need to disable buffering to actually know that the request was
556 * successfully sent to the server (so that we should expect a result
557 * back). It would be nice to do this in buffered mode, but then it
558 * would be complex to handle all error situations if we got to send
559 * some of the messages, and then we failed on writing out some others
560 * and we used the callback interface from memcached_mget_execute so
561 * that we might have processed some of the responses etc. For now,
562 * just make sure we work _correctly_
564 struct libmemcached_io_vector_st vector
[]=
566 { .length
= sizeof(request
.bytes
), .buffer
= request
.bytes
},
567 { .length
= ptr
->prefix_key_length
, .buffer
= ptr
->prefix_key
},
568 { .length
= key_length
[x
], .buffer
= keys
[x
] }
571 if (memcached_io_writev(instance
, vector
, 3, true) == -1)
573 memcached_io_reset(instance
);
574 dead_servers
[server
]= true;
579 memcached_server_response_increment(instance
);
580 hash
[x
]= memcached_server_count(ptr
);
590 static memcached_return_t
binary_mget_by_key(memcached_st
*ptr
,
591 uint32_t master_server_key
,
592 bool is_master_key_set
,
593 const char * const *keys
,
594 const size_t *key_length
,
595 size_t number_of_keys
,
598 memcached_return_t rc
;
600 if (ptr
->number_of_replicas
== 0)
602 rc
= simple_binary_mget(ptr
, master_server_key
, is_master_key_set
,
603 keys
, key_length
, number_of_keys
, mget_mode
);
610 hash
= libmemcached_malloc(ptr
, sizeof(uint32_t) * number_of_keys
);
611 dead_servers
= libmemcached_calloc(ptr
, memcached_server_count(ptr
), sizeof(bool));
613 if (hash
== NULL
|| dead_servers
== NULL
)
615 libmemcached_free(ptr
, hash
);
616 libmemcached_free(ptr
, dead_servers
);
617 return MEMCACHED_MEMORY_ALLOCATION_FAILURE
;
620 if (is_master_key_set
)
622 for (size_t x
= 0; x
< number_of_keys
; x
++)
624 hash
[x
]= master_server_key
;
629 for (size_t x
= 0; x
< number_of_keys
; x
++)
631 hash
[x
]= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
635 rc
= replication_binary_mget(ptr
, hash
, dead_servers
, keys
,
636 key_length
, number_of_keys
);
638 libmemcached_free(ptr
, hash
);
639 libmemcached_free(ptr
, dead_servers
);
641 return MEMCACHED_SUCCESS
;