2 +--------------------------------------------------------------------+
3 | libmemcached-awesome - C/C++ Client Library for memcached |
4 +--------------------------------------------------------------------+
5 | Redistribution and use in source and binary forms, with or without |
6 | modification, are permitted under the terms of the BSD license. |
7 | You should have received a copy of the license in a bundled file |
8 | named LICENSE; in case you did not receive a copy you can review |
9 | the terms online at: https://opensource.org/licenses/BSD-3-Clause |
10 +--------------------------------------------------------------------+
11 | Copyright (c) 2006-2014 Brian Aker https://datadifferential.com/ |
12 | Copyright (c) 2020-2021 Michael Wallner https://awesome.co/ |
13 +--------------------------------------------------------------------+
16 #include "libmemcached/common.h"
17 #include "p9y/random.hpp"
19 char *memcached_get(memcached_st
*ptr
, const char *key
, size_t key_length
, size_t *value_length
,
20 uint32_t *flags
, memcached_return_t
*error
) {
21 return memcached_get_by_key(ptr
, NULL
, 0, key
, key_length
, value_length
, flags
, error
);
24 static memcached_return_t
mget_by_key_real(memcached_st
*ptr
, const char *group_key
,
25 size_t group_key_length
, const char *const *keys
,
26 const size_t *key_length
, size_t number_of_keys
,
27 const bool mget_mode
);
28 char *memcached_get_by_key(memcached_st
*shell
, const char *group_key
, size_t group_key_length
,
29 const char *key
, size_t key_length
, size_t *value_length
,
30 uint32_t *flags
, memcached_return_t
*error
) {
31 Memcached
*ptr
= memcached2Memcached(shell
);
32 memcached_return_t unused
;
37 uint64_t query_id
= 0;
39 query_id
= ptr
->query_id
;
43 *error
= mget_by_key_real(ptr
, group_key
, group_key_length
, (const char *const *) &key
,
44 &key_length
, 1, false);
46 assert_msg(ptr
->query_id
== query_id
+ 1,
47 "Programmer error, the query_id was not incremented.");
50 if (memcached_failed(*error
)) {
52 if (memcached_has_current_error(*ptr
)) // Find the most accurate error
54 *error
= memcached_last_error(ptr
);
65 char *value
= memcached_fetch(ptr
, NULL
, NULL
, value_length
, flags
, error
);
66 assert_msg(ptr
->query_id
== query_id
+ 1, "Programmer error, the query_id was not incremented.");
68 /* This is for historical reasons */
69 if (*error
== MEMCACHED_END
) {
70 *error
= MEMCACHED_NOTFOUND
;
73 if (ptr
->get_key_failure
and *error
== MEMCACHED_NOTFOUND
) {
74 memcached_result_st key_failure_result
;
75 memcached_result_st
*result_ptr
= memcached_result_create(ptr
, &key_failure_result
);
76 memcached_return_t rc
= ptr
->get_key_failure(ptr
, key
, key_length
, result_ptr
);
78 /* On all failure drop to returning NULL */
79 if (rc
== MEMCACHED_SUCCESS
or rc
== MEMCACHED_BUFFERED
) {
80 if (rc
== MEMCACHED_BUFFERED
) {
81 uint64_t latch
; /* We use latch to track the state of the original socket */
82 latch
= memcached_behavior_get(ptr
, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
);
84 memcached_behavior_set(ptr
, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
, 1);
87 rc
= memcached_set(ptr
, key
, key_length
, (memcached_result_value(result_ptr
)),
88 (memcached_result_length(result_ptr
)), 0,
89 (memcached_result_flags(result_ptr
)));
91 if (rc
== MEMCACHED_BUFFERED
and latch
== 0) {
92 memcached_behavior_set(ptr
, MEMCACHED_BEHAVIOR_BUFFER_REQUESTS
, 0);
95 rc
= memcached_set(ptr
, key
, key_length
, (memcached_result_value(result_ptr
)),
96 (memcached_result_length(result_ptr
)), 0,
97 (memcached_result_flags(result_ptr
)));
100 if (rc
== MEMCACHED_SUCCESS
or rc
== MEMCACHED_BUFFERED
) {
103 *value_length
= memcached_result_length(result_ptr
);
106 *flags
= memcached_result_flags(result_ptr
);
108 char *result_value
= memcached_string_take_value(&result_ptr
->value
);
109 memcached_result_free(result_ptr
);
115 memcached_result_free(result_ptr
);
117 assert_msg(ptr
->query_id
== query_id
+ 1,
118 "Programmer error, the query_id was not incremented.");
126 memcached_return_t
memcached_mget(memcached_st
*ptr
, const char *const *keys
,
127 const size_t *key_length
, 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
, const uint32_t master_server_key
,
132 const bool is_group_key_set
, const char *const *keys
,
133 const size_t *key_length
, const size_t number_of_keys
,
134 const bool mget_mode
);
136 static memcached_return_t
mget_by_key_real(memcached_st
*ptr
, const char *group_key
,
137 size_t group_key_length
, const char *const *keys
,
138 const size_t *key_length
, size_t number_of_keys
,
139 const bool mget_mode
) {
140 bool failures_occurred_in_sending
= false, success_happened
= false;
141 const char *get_command
= "get";
142 uint8_t get_command_length
= 3;
143 unsigned int master_server_key
= (unsigned int) -1; /* 0 is a valid server id! */
145 memcached_return_t rc
;
146 if (memcached_failed(rc
= initialize_query(ptr
, true))) {
150 if (memcached_is_udp(ptr
)) {
151 return memcached_set_error(*ptr
, MEMCACHED_NOT_SUPPORTED
, MEMCACHED_AT
);
154 LIBMEMCACHED_MEMCACHED_MGET_START();
156 if (number_of_keys
== 0) {
157 return memcached_set_error(*ptr
, MEMCACHED_INVALID_ARGUMENTS
, MEMCACHED_AT
,
158 memcached_literal_param("Numbers of keys provided was zero"));
161 if (memcached_failed((rc
= memcached_key_test(*ptr
, keys
, key_length
, number_of_keys
)))) {
162 assert(memcached_last_error(ptr
) == rc
);
167 bool is_group_key_set
= false;
168 if (group_key
and group_key_length
) {
170 memcached_generate_hash_with_redistribution(ptr
, group_key
, group_key_length
);
171 is_group_key_set
= true;
175 Here is where we pay for the non-block API. We need to remove any data sitting
176 in the queue before we start our get.
178 It might be optimum to bounce the connection if count > some number.
180 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++) {
181 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, x
);
183 if (instance
->response_count()) {
184 char buffer
[MEMCACHED_DEFAULT_COMMAND_SIZE
];
186 if (ptr
->flags
.no_block
|| ptr
->flags
.buffer_requests
) {
187 memcached_io_write(instance
);
190 while (instance
->response_count()) {
191 (void) memcached_response(instance
, buffer
, MEMCACHED_DEFAULT_COMMAND_SIZE
, &ptr
->result
);
196 if (memcached_is_binary(ptr
)) {
197 return binary_mget_by_key(ptr
, master_server_key
, is_group_key_set
, keys
, key_length
,
198 number_of_keys
, mget_mode
);
201 if (memcached_is_meta(ptr
)) {
202 size_t hosts_connected
= 0;
204 for (uint32_t x
= 0; x
< number_of_keys
; ++x
) {
206 libmemcached_io_vector_st io_vec
[8] = {};
208 io_vec
[io_num
++] = {memcached_literal_param("mg ")};
209 io_vec
[io_num
++] = {memcached_array_string(ptr
->_namespace
), memcached_array_size(ptr
->_namespace
)};
210 io_vec
[io_num
++] = {keys
[x
], key_length
[x
]};
211 if (memcached_is_cas(ptr
)) {
212 io_vec
[io_num
++] = { memcached_literal_param(" c")};
214 io_vec
[io_num
++] = {memcached_literal_param(" k t f v\r\n")};
217 if (is_group_key_set
) {
218 server_key
= master_server_key
;
220 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
223 auto *instance
= memcached_instance_fetch(ptr
, server_key
);
224 if (!instance
->response_count()) {
225 rc
= memcached_connect(instance
);
227 if (memcached_failed(rc
)) {
228 memcached_set_error(*instance
, rc
, MEMCACHED_AT
);
233 if (!memcached_io_writev(instance
, io_vec
, io_num
, false)) {
234 failures_occurred_in_sending
= true;
237 memcached_instance_response_increment(instance
);
240 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++) {
241 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, x
);
243 if (instance
->response_count()) {
244 /* We need to do something about non-connected hosts in the future */
245 if (!memcached_io_write(instance
)) {
246 failures_occurred_in_sending
= true;
248 success_happened
= true;
253 if (ptr
->flags
.support_cas
) {
254 get_command
= "gets";
255 get_command_length
= 4;
259 If a server fails we warn about errors and start all over with sending keys
262 WATCHPOINT_ASSERT(rc
== MEMCACHED_SUCCESS
);
263 size_t hosts_connected
= 0;
264 for (uint32_t x
= 0; x
< number_of_keys
; x
++) {
267 if (is_group_key_set
) {
268 server_key
= master_server_key
;
270 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
273 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, server_key
);
275 libmemcached_io_vector_st vector
[] = {
276 {get_command
, get_command_length
},
277 {memcached_literal_param(" ")},
278 {memcached_array_string(ptr
->_namespace
), memcached_array_size(ptr
->_namespace
)},
279 {keys
[x
], key_length
[x
]}};
281 if (instance
->response_count() == 0) {
282 rc
= memcached_connect(instance
);
284 if (memcached_failed(rc
)) {
285 memcached_set_error(*instance
, rc
, MEMCACHED_AT
);
290 if ((memcached_io_writev(instance
, vector
, 1, false)) == false) {
291 failures_occurred_in_sending
= true;
294 WATCHPOINT_ASSERT(instance
->cursor_active_
== 0);
295 memcached_instance_response_increment(instance
);
296 WATCHPOINT_ASSERT(instance
->cursor_active_
== 1);
300 if ((memcached_io_writev(instance
, (vector
+ 1), 3, false)) == false) {
301 memcached_instance_response_reset(instance
);
302 failures_occurred_in_sending
= true;
308 if (hosts_connected
== 0) {
309 LIBMEMCACHED_MEMCACHED_MGET_END();
311 if (memcached_failed(rc
)) {
315 return memcached_set_error(*ptr
, MEMCACHED_NO_SERVERS
, MEMCACHED_AT
);
319 Should we muddle on if some servers are dead?
321 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); x
++) {
322 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, x
);
324 if (instance
->response_count()) {
325 /* We need to do something about non-connnected hosts in the future */
326 if ((memcached_io_write(instance
, "\r\n", 2, true)) == -1) {
327 failures_occurred_in_sending
= true;
329 success_happened
= true;
335 LIBMEMCACHED_MEMCACHED_MGET_END();
337 if (failures_occurred_in_sending
and success_happened
) {
338 return MEMCACHED_SOME_ERRORS
;
341 if (success_happened
) {
342 return MEMCACHED_SUCCESS
;
345 return MEMCACHED_FAILURE
; // Complete failure occurred
348 memcached_return_t
memcached_mget_by_key(memcached_st
*shell
, const char *group_key
,
349 size_t group_key_length
, const char *const *keys
,
350 const size_t *key_length
, size_t number_of_keys
) {
351 Memcached
*ptr
= memcached2Memcached(shell
);
352 return mget_by_key_real(ptr
, group_key
, group_key_length
, keys
, key_length
, number_of_keys
, true);
355 memcached_return_t
memcached_mget_execute(memcached_st
*ptr
, const char *const *keys
,
356 const size_t *key_length
, size_t number_of_keys
,
357 memcached_execute_fn
*callback
, void *context
,
358 unsigned int number_of_callbacks
) {
359 return memcached_mget_execute_by_key(ptr
, NULL
, 0, keys
, key_length
, number_of_keys
, callback
,
360 context
, number_of_callbacks
);
363 memcached_return_t
memcached_mget_execute_by_key(memcached_st
*shell
, const char *group_key
,
364 size_t group_key_length
, const char *const *keys
,
365 const size_t *key_length
, size_t number_of_keys
,
366 memcached_execute_fn
*callback
, void *context
,
367 unsigned int number_of_callbacks
) {
368 Memcached
*ptr
= memcached2Memcached(shell
);
369 memcached_return_t rc
;
370 if (memcached_failed(rc
= initialize_query(ptr
, false))) {
374 if (memcached_is_udp(ptr
)) {
375 return memcached_set_error(*ptr
, MEMCACHED_NOT_SUPPORTED
, MEMCACHED_AT
);
378 if (memcached_is_binary(ptr
) == false) {
379 return memcached_set_error(
380 *ptr
, MEMCACHED_NOT_SUPPORTED
, MEMCACHED_AT
,
381 memcached_literal_param(
382 "ASCII protocol is not supported for memcached_mget_execute_by_key()"));
385 memcached_callback_st
*original_callbacks
= ptr
->callbacks
;
386 memcached_callback_st cb
= {callback
, context
, number_of_callbacks
};
388 ptr
->callbacks
= &cb
;
389 rc
= memcached_mget_by_key(ptr
, group_key
, group_key_length
, keys
, key_length
, number_of_keys
);
390 ptr
->callbacks
= original_callbacks
;
395 static memcached_return_t
simple_binary_mget(memcached_st
*ptr
, const uint32_t master_server_key
,
396 bool is_group_key_set
, const char *const *keys
,
397 const size_t *key_length
, const size_t number_of_keys
,
398 const bool mget_mode
) {
399 memcached_return_t rc
= MEMCACHED_NOTFOUND
;
401 bool flush
= (number_of_keys
== 1);
403 if (memcached_failed(rc
= memcached_key_test(*ptr
, keys
, key_length
, number_of_keys
))) {
408 If a server fails we warn about errors and start all over with sending keys
411 for (uint32_t x
= 0; x
< number_of_keys
; ++x
) {
414 if (is_group_key_set
) {
415 server_key
= master_server_key
;
417 server_key
= memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
420 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, server_key
);
422 if (instance
->response_count() == 0) {
423 rc
= memcached_connect(instance
);
424 if (memcached_failed(rc
)) {
429 protocol_binary_request_getk request
= {}; //= {.bytes= {0}};
430 initialize_binary_request(instance
, request
.message
.header
);
432 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETKQ
;
434 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETK
;
439 memcached_return_t vk
= memcached_validate_key_length(key_length
[x
], ptr
->flags
.binary_protocol
);
440 if (memcached_failed(rc
= memcached_key_test(*memc
, (const char **)&key
, &key_length
, 1)))
442 memcached_set_error(ptr
, vk
, MEMCACHED_AT
, memcached_literal_param("Key was too long."));
446 memcached_io_reset(instance
);
454 request
.message
.header
.request
.keylen
=
455 htons((uint16_t)(key_length
[x
] + memcached_array_size(ptr
->_namespace
)));
456 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
457 request
.message
.header
.request
.bodylen
=
458 htonl((uint32_t)(key_length
[x
] + memcached_array_size(ptr
->_namespace
)));
460 libmemcached_io_vector_st vector
[] = {
461 {request
.bytes
, sizeof(request
.bytes
)},
462 {memcached_array_string(ptr
->_namespace
), memcached_array_size(ptr
->_namespace
)},
463 {keys
[x
], key_length
[x
]}};
465 if (memcached_io_writev(instance
, vector
, 3, flush
) == false) {
466 memcached_server_response_reset(instance
);
467 rc
= MEMCACHED_SOME_ERRORS
;
471 /* We just want one pending response per server */
472 memcached_server_response_reset(instance
);
473 memcached_server_response_increment(instance
);
474 if ((x
> 0 and x
== ptr
->io_key_prefetch
) and memcached_flush_buffers(ptr
) != MEMCACHED_SUCCESS
)
476 rc
= MEMCACHED_SOME_ERRORS
;
482 Send a noop command to flush the buffers
484 protocol_binary_request_noop request
= {}; //= {.bytes= {0}};
485 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_NOOP
;
486 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
488 for (uint32_t x
= 0; x
< memcached_server_count(ptr
); ++x
) {
489 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, x
);
491 if (instance
->response_count()) {
492 initialize_binary_request(instance
, request
.message
.header
);
493 if ((memcached_io_write(instance
) == false)
494 or (memcached_io_write(instance
, request
.bytes
, sizeof(request
.bytes
), true) == -1))
496 memcached_instance_response_reset(instance
);
497 memcached_io_reset(instance
);
498 rc
= MEMCACHED_SOME_ERRORS
;
507 static memcached_return_t
replication_binary_mget(memcached_st
*ptr
, uint32_t *hash
,
508 bool *dead_servers
, const char *const *keys
,
509 const size_t *key_length
,
510 const size_t number_of_keys
) {
511 memcached_return_t rc
= MEMCACHED_NOTFOUND
;
513 uint64_t randomize_read
= memcached_behavior_get(ptr
, MEMCACHED_BEHAVIOR_RANDOMIZE_REPLICA_READ
);
515 if (randomize_read
) {
516 start
= (uint32_t) random() % (uint32_t)(ptr
->number_of_replicas
+ 1);
519 /* Loop for each replica */
520 for (uint32_t replica
= 0; replica
<= ptr
->number_of_replicas
; ++replica
) {
523 for (uint32_t x
= 0; x
< number_of_keys
; ++x
) {
524 if (hash
[x
] == memcached_server_count(ptr
)) {
525 continue; /* Already successfully sent */
528 uint32_t server
= hash
[x
] + replica
;
530 /* In case of randomized reads */
531 if (randomize_read
and ((server
+ start
) <= (hash
[x
] + ptr
->number_of_replicas
))) {
535 while (server
>= memcached_server_count(ptr
)) {
536 server
-= memcached_server_count(ptr
);
539 if (dead_servers
[server
]) {
543 memcached_instance_st
*instance
= memcached_instance_fetch(ptr
, server
);
545 if (instance
->response_count() == 0) {
546 rc
= memcached_connect(instance
);
548 if (memcached_failed(rc
)) {
549 memcached_io_reset(instance
);
550 dead_servers
[server
] = true;
556 protocol_binary_request_getk request
= {};
557 initialize_binary_request(instance
, request
.message
.header
);
558 request
.message
.header
.request
.opcode
= PROTOCOL_BINARY_CMD_GETK
;
559 request
.message
.header
.request
.keylen
=
560 htons((uint16_t)(key_length
[x
] + memcached_array_size(ptr
->_namespace
)));
561 request
.message
.header
.request
.datatype
= PROTOCOL_BINARY_RAW_BYTES
;
562 request
.message
.header
.request
.bodylen
=
563 htonl((uint32_t)(key_length
[x
] + memcached_array_size(ptr
->_namespace
)));
566 * We need to disable buffering to actually know that the request was
567 * successfully sent to the server (so that we should expect a result
568 * back). It would be nice to do this in buffered mode, but then it
569 * would be complex to handle all error situations if we got to send
570 * some of the messages, and then we failed on writing out some others
571 * and we used the callback interface from memcached_mget_execute so
572 * that we might have processed some of the responses etc. For now,
573 * just make sure we work _correctly_
575 libmemcached_io_vector_st vector
[] = {
576 {request
.bytes
, sizeof(request
.bytes
)},
577 {memcached_array_string(ptr
->_namespace
), memcached_array_size(ptr
->_namespace
)},
578 {keys
[x
], key_length
[x
]}};
580 if (memcached_io_writev(instance
, vector
, 3, true) == false) {
581 memcached_io_reset(instance
);
582 dead_servers
[server
] = true;
587 memcached_server_response_increment(instance
);
588 hash
[x
] = memcached_server_count(ptr
);
599 static memcached_return_t
binary_mget_by_key(memcached_st
*ptr
, const uint32_t master_server_key
,
600 bool is_group_key_set
, const char *const *keys
,
601 const size_t *key_length
, const size_t number_of_keys
,
602 const bool mget_mode
) {
603 if (ptr
->number_of_replicas
== 0) {
604 return simple_binary_mget(ptr
, master_server_key
, is_group_key_set
, keys
, key_length
,
605 number_of_keys
, mget_mode
);
608 uint32_t *hash
= libmemcached_xvalloc(ptr
, number_of_keys
, uint32_t);
609 bool *dead_servers
= libmemcached_xcalloc(ptr
, memcached_server_count(ptr
), bool);
611 if (hash
== NULL
or dead_servers
== NULL
) {
612 libmemcached_free(ptr
, hash
);
613 libmemcached_free(ptr
, dead_servers
);
614 return MEMCACHED_MEMORY_ALLOCATION_FAILURE
;
617 if (is_group_key_set
) {
618 for (size_t x
= 0; x
< number_of_keys
; x
++) {
619 hash
[x
] = master_server_key
;
622 for (size_t x
= 0; x
< number_of_keys
; x
++) {
623 hash
[x
] = memcached_generate_hash_with_redistribution(ptr
, keys
[x
], key_length
[x
]);
627 memcached_return_t rc
=
628 replication_binary_mget(ptr
, hash
, dead_servers
, keys
, key_length
, number_of_keys
);
630 WATCHPOINT_IFERROR(rc
);
631 libmemcached_free(ptr
, hash
);
632 libmemcached_free(ptr
, dead_servers
);
634 return MEMCACHED_SUCCESS
;