+ * Replication support has been added to the library.
+
0.17
* MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT added for connect timeout in
non-block mode.
Partitioning based on keys is supported in the library. Using the key partioning
functions it is possible to group sets of object onto servers.
+Replication can be done across multiple nodes. libmemcached(3) will spread
+data out when consistent hashing has been enabled and replication has been
+specified to send data to more then one node. This feature is considered
+very experimental at this stage.
+
C<memcached_st> structures are thread-safe, but each thread must
contain its own structure (that is, if you want to share these among
threads you must provide your own locking). No global variables are
=over 4
+=item MEMCACHED_BEHAVIOR_REPLICAS
+
+By default libmemcached(3) stores data in just one node of the cluster. Setting this value
+to a number will cause that number of copies to be kept. The value must be greater then
+zero, and must be at most the same value as the number of hosts in the cluster.
+
=item MEMCACHED_BEHAVIOR_NO_BLOCK
Causes libmemcached(3) to use asychronous IO. This is the fastest transport
#define MEMCACHED_MAX_HOST_LENGTH 64
#define MEMCACHED_WHEEL_SIZE 1024
#define MEMCACHED_STRIDE 4
+#define MEMCACHED_MAX_REPLICAS 4
#define MEMCACHED_DEFAULT_TIMEOUT INT32_MAX
/* string value */
MEMCACHED_BEHAVIOR_SORT_HOSTS,
MEMCACHED_BEHAVIOR_VERIFY_KEY,
MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT,
+ MEMCACHED_BEHAVIOR_REPLICAS,
} memcached_behavior;
typedef enum {
memcached_free_function call_free;
memcached_malloc_function call_malloc;
memcached_realloc_function call_realloc;
+ uint8_t number_of_replicas;
#ifdef NOT_USED /* Future Use */
- uint8_t replicas;
memcached_return warning;
#endif
};
memcached_io.c \
md5.c \
memcached_key.c \
+ memcached_mget.c \
memcached_quit.c \
memcached_parse.c \
memcached_response.c \
WATCHPOINT_ASSERT(result_ptr);
ptr->poll_timeout= MEMCACHED_DEFAULT_TIMEOUT;
ptr->distribution= MEMCACHED_DISTRIBUTION_MODULA;
+ ptr->number_of_replicas= 1;
return ptr;
}
uint64_t *value)
{
size_t send_length;
- memcached_return rc;
char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
unsigned int server_key;
+ uint8_t replicas= 0;
+ memcached_return rc[MEMCACHED_MAX_REPLICAS];
if (key_length == 0)
return MEMCACHED_NO_KEY_PROVIDED;
if (send_length >= MEMCACHED_DEFAULT_COMMAND_SIZE)
return MEMCACHED_WRITE_FAILURE;
- rc= memcached_do(&ptr->hosts[server_key], buffer, send_length, 1);
- if (rc != MEMCACHED_SUCCESS)
- return rc;
-
- rc= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
-
- /*
- So why recheck responce? Because the protocol is brain dead :)
- The number returned might end up equaling one of the string
- values. Less chance of a mistake with strncmp() so we will
- use it. We still called memcached_response() though since it
- worked its magic for non-blocking IO.
- */
- if (!strncmp(buffer, "ERROR\r\n", 7))
+ do
{
- *value= 0;
- rc= MEMCACHED_PROTOCOL_ERROR;
- }
- else if (!strncmp(buffer, "NOT_FOUND\r\n", 11))
+ rc[replicas]= memcached_do(&ptr->hosts[server_key], buffer, send_length, 1);
+ if (rc[replicas] != MEMCACHED_SUCCESS)
+ goto error;
+
+ rc[replicas]= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
+
+ /*
+ So why recheck responce? Because the protocol is brain dead :)
+ The number returned might end up equaling one of the string
+ values. Less chance of a mistake with strncmp() so we will
+ use it. We still called memcached_response() though since it
+ worked its magic for non-blocking IO.
+ */
+ if (!strncmp(buffer, "ERROR\r\n", 7))
+ {
+ *value= 0;
+ rc[replicas]= MEMCACHED_PROTOCOL_ERROR;
+ }
+ else if (!strncmp(buffer, "NOT_FOUND\r\n", 11))
+ {
+ *value= 0;
+ rc[replicas]= MEMCACHED_NOTFOUND;
+ }
+ else
+ {
+ *value= (uint64_t)strtoll(buffer, (char **)NULL, 10);
+ rc[replicas]= MEMCACHED_SUCCESS;
+ }
+ /* On error we just jump to the next potential server */
+error:
+ if (replicas > 1 && ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT)
+ {
+ if (server_key == (ptr->number_of_hosts - 1))
+ server_key= 0;
+ else
+ server_key++;
+ }
+ } while ((++replicas) < ptr->number_of_replicas);
+
+ /* As long as one object gets stored, we count this as a success */
+ while (replicas--)
{
- *value= 0;
- rc= MEMCACHED_NOTFOUND;
- }
- else
- {
- *value= (uint64_t)strtoll(buffer, (char **)NULL, 10);
- rc= MEMCACHED_SUCCESS;
+ if (rc[replicas] == MEMCACHED_STORED)
+ return MEMCACHED_SUCCESS;
}
- return rc;
+ return rc[0];
}
memcached_return memcached_increment(memcached_st *ptr,
{
switch (flag)
{
+ case MEMCACHED_BEHAVIOR_REPLICAS:
+ {
+ uint8_t number_of_replicas= (uint8_t)data;
+
+ if (number_of_replicas > ptr->number_of_hosts || number_of_replicas == 0 || number_of_replicas > MEMCACHED_MAX_REPLICAS)
+ return MEMCACHED_FAILURE;
+ else
+ ptr->number_of_replicas= number_of_replicas;
+ break;
+ }
case MEMCACHED_BEHAVIOR_SUPPORT_CAS:
set_behavior_flag(ptr, MEM_SUPPORT_CAS, data);
break;
switch (flag)
{
+ case MEMCACHED_BEHAVIOR_REPLICAS:
+ return (unsigned long long)ptr->number_of_replicas;
case MEMCACHED_BEHAVIOR_SUPPORT_CAS:
temp_flag= MEM_SUPPORT_CAS;
break;
{
char to_write;
size_t send_length;
- memcached_return rc;
char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
unsigned int server_key;
-
- LIBMEMCACHED_MEMCACHED_DELETE_START();
+ uint8_t replicas= 0;
+ memcached_return rc[MEMCACHED_MAX_REPLICAS];
if (key_length == 0)
return MEMCACHED_NO_KEY_PROVIDED;
if (send_length >= MEMCACHED_DEFAULT_COMMAND_SIZE)
{
- rc= MEMCACHED_WRITE_FAILURE;
+ rc[replicas]= MEMCACHED_WRITE_FAILURE;
goto error;
}
to_write= (ptr->flags & MEM_BUFFER_REQUESTS) ? 0 : 1;
- rc= memcached_do(&ptr->hosts[server_key], buffer, send_length, to_write);
- if (rc != MEMCACHED_SUCCESS)
- goto error;
-
- if ((ptr->flags & MEM_BUFFER_REQUESTS))
+ do
{
- rc= MEMCACHED_BUFFERED;
- }
- else
+ rc[replicas]= memcached_do(&ptr->hosts[server_key], buffer, send_length, to_write);
+ if (rc[replicas] != MEMCACHED_SUCCESS)
+ goto error;
+
+ if ((ptr->flags & MEM_BUFFER_REQUESTS))
+ {
+ rc[replicas]= MEMCACHED_BUFFERED;
+ }
+ else
+ {
+ rc[replicas]= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
+ if (rc[replicas] == MEMCACHED_DELETED)
+ rc[replicas]= MEMCACHED_SUCCESS;
+ }
+
+ /* On error we just jump to the next potential server */
+error:
+ if (replicas > 1 && ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT)
+ {
+ if (server_key == (ptr->number_of_hosts - 1))
+ server_key= 0;
+ else
+ server_key++;
+ }
+ } while ((++replicas) < ptr->number_of_replicas);
+
+ /* As long as one object gets stored, we count this as a success */
+ while (replicas--)
{
- rc= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
- if (rc == MEMCACHED_DELETED)
- rc= MEMCACHED_SUCCESS;
+ if (rc[replicas] == MEMCACHED_DELETED)
+ return MEMCACHED_SUCCESS;
+ else if (rc[replicas] == MEMCACHED_DELETED)
+ rc[replicas]= MEMCACHED_BUFFERED;
}
-error:
- LIBMEMCACHED_MEMCACHED_DELETE_END();
- return rc;
+ return rc[0];
}
uint32_t *flags,
memcached_return *error)
{
- char *value;
- size_t dummy_length;
- uint32_t dummy_flags;
- memcached_return dummy_error;
-
- /* Request the key */
- *error= memcached_mget_by_key(ptr,
- master_key,
- master_key_length,
- &key, &key_length, 1);
-
- value= memcached_fetch(ptr, NULL, NULL,
- value_length, flags, error);
- /* This is for historical reasons */
- if (*error == MEMCACHED_END)
- *error= MEMCACHED_NOTFOUND;
-
- if (value == NULL)
- return NULL;
-
- (void)memcached_fetch(ptr, NULL, NULL,
- &dummy_length, &dummy_flags,
- &dummy_error);
- WATCHPOINT_ASSERT(dummy_length == 0);
-
- return value;
-}
-
-memcached_return memcached_mget(memcached_st *ptr,
- char **keys, size_t *key_length,
- unsigned int number_of_keys)
-{
- return memcached_mget_by_key(ptr, NULL, 0, keys, key_length, number_of_keys);
-}
-
-memcached_return memcached_mget_by_key(memcached_st *ptr,
- char *master_key, size_t master_key_length,
- char **keys, size_t *key_length,
- unsigned int number_of_keys)
-{
- unsigned int x;
- memcached_return rc= MEMCACHED_NOTFOUND;
- char *get_command= "get ";
- uint8_t get_command_length= 4;
- unsigned int master_server_key= 0;
-
- LIBMEMCACHED_MEMCACHED_MGET_START();
- ptr->cursor_server= 0;
-
- if (number_of_keys == 0)
- return MEMCACHED_NOTFOUND;
+ unsigned int server_key;
+ size_t send_length;
+ char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
+ memcached_result_st *result_buffer= &ptr->result;
+ memcached_return rc[MEMCACHED_MAX_REPLICAS];
+ uint8_t replicas= 0;
if (ptr->number_of_hosts == 0)
- return MEMCACHED_NO_SERVERS;
-
- if ((ptr->flags & MEM_VERIFY_KEY) && (memcachd_key_test(keys, key_length, number_of_keys) == MEMCACHED_BAD_KEY_PROVIDED))
- return MEMCACHED_BAD_KEY_PROVIDED;
+ {
+ *error= MEMCACHED_NO_SERVERS;
+ return NULL;
+ }
- if (ptr->flags & MEM_SUPPORT_CAS)
+ if ((ptr->flags & MEM_VERIFY_KEY) && (memcachd_key_test(&key, &key_length, 1) == MEMCACHED_BAD_KEY_PROVIDED))
{
- get_command= "gets ";
- get_command_length= 5;
+ *value_length= 0;
+ *error= MEMCACHED_BAD_KEY_PROVIDED;
+ return NULL;
}
- if (master_key && master_key_length)
- master_server_key= memcached_generate_hash(ptr, master_key, master_key_length);
+ if (master_key)
+ server_key= memcached_generate_hash(ptr, master_key, master_key_length);
+ else
+ server_key= memcached_generate_hash(ptr, key, key_length);
- /*
- Here is where we pay for the non-block API. We need to remove any data sitting
- in the queue before we start our get.
+ send_length= snprintf(buffer, MEMCACHED_DEFAULT_COMMAND_SIZE,
+ "get %.*s\r\n", (int)key_length, key);
- It might be optimum to bounce the connection if count > some number.
- */
- for (x= 0; x < ptr->number_of_hosts; x++)
+ do
{
- if (memcached_server_response_count(&ptr->hosts[x]))
+ if (memcached_server_response_count(&ptr->hosts[server_key]))
{
char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
if (ptr->flags & MEM_NO_BLOCK)
- (void)memcached_io_write(&ptr->hosts[x], NULL, 0, 1);
+ (void)memcached_io_write(&ptr->hosts[server_key], NULL, 0, 1);
- while(memcached_server_response_count(&ptr->hosts[x]))
- (void)memcached_response(&ptr->hosts[x], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, &ptr->result);
+ while(memcached_server_response_count(&ptr->hosts[server_key]))
+ (void)memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, result_buffer);
}
- }
- /*
- If a server fails we warn about errors and start all over with sending keys
- to the server.
- */
- for (x= 0; x < number_of_keys; x++)
- {
- unsigned int server_key;
+ rc[replicas]= memcached_do(&ptr->hosts[server_key], buffer, send_length, 1);
+ if (rc[replicas] != MEMCACHED_SUCCESS)
+ goto error;
- if (master_server_key)
- server_key= master_server_key;
- else
- server_key= memcached_generate_hash(ptr, keys[x], key_length[x]);
+ rc[replicas]= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, result_buffer);
- if (memcached_server_response_count(&ptr->hosts[server_key]) == 0)
- {
- rc= memcached_connect(&ptr->hosts[server_key]);
-
- if (rc != MEMCACHED_SUCCESS)
- continue;
-
- if ((memcached_io_write(&ptr->hosts[server_key], get_command, get_command_length, 0)) == -1)
- {
- rc= MEMCACHED_SOME_ERRORS;
- continue;
- }
- WATCHPOINT_ASSERT(ptr->hosts[server_key].cursor_active == 0);
- memcached_server_response_increment(&ptr->hosts[server_key]);
- WATCHPOINT_ASSERT(ptr->hosts[server_key].cursor_active == 1);
- }
-
- if ((memcached_io_write(&ptr->hosts[server_key], keys[x], key_length[x], 0)) == -1)
+ /* On no key found, we check the replica */
+ if (rc[replicas] == MEMCACHED_END) /* END means that we move on to the next */
{
memcached_server_response_reset(&ptr->hosts[server_key]);
- rc= MEMCACHED_SOME_ERRORS;
- continue;
}
-
- if ((memcached_io_write(&ptr->hosts[server_key], " ", 1, 0)) == -1)
+ else if (rc[replicas] == MEMCACHED_SUCCESS)
{
- memcached_server_response_reset(&ptr->hosts[server_key]);
- rc= MEMCACHED_SOME_ERRORS;
- continue;
+ *value_length= memcached_string_length(&result_buffer->value);
+
+ if (result_buffer->flags)
+ *flags= result_buffer->flags;
+
+ return memcached_string_c_copy(&result_buffer->value);
}
- }
- /*
- Should we muddle on if some servers are dead?
- */
- for (x= 0; x < ptr->number_of_hosts; x++)
- {
- if (memcached_server_response_count(&ptr->hosts[x]))
+ /* On error we just jump to the next potential server */
+error:
+ if (replicas > 1 && ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT)
{
- /* We need to do something about non-connnected hosts in the future */
- if ((memcached_io_write(&ptr->hosts[x], "\r\n", 2, 1)) == -1)
- {
- rc= MEMCACHED_SOME_ERRORS;
- }
+ if (server_key == (ptr->number_of_hosts - 1))
+ server_key= 0;
+ else
+ server_key++;
}
- }
+ } while ((++replicas) < ptr->number_of_replicas);
+
+ /* TODO: An error on replica 1 of host down, but not found on 2, will give wrong error */
+ /* This is for historical reasons */
+ if (rc[0] == MEMCACHED_END)
+ *error= MEMCACHED_NOTFOUND;
+ else
+ *error= rc[0];
+
+ *value_length= 0;
- LIBMEMCACHED_MEMCACHED_MGET_END();
- return rc;
+ return NULL;
}
char to_write;
size_t write_length;
ssize_t sent_length;
- memcached_return rc;
+ memcached_return rc[MEMCACHED_MAX_REPLICAS];
char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
unsigned int server_key;
+ uint8_t replicas= 0;
WATCHPOINT_ASSERT(!(value == NULL && value_length > 0));
WATCHPOINT_ASSERT(!(value && value_length == 0));
(unsigned long long)expiration, value_length);
if (write_length >= MEMCACHED_DEFAULT_COMMAND_SIZE)
- {
- rc= MEMCACHED_WRITE_FAILURE;
- goto error;
- }
-
- rc= memcached_do(&ptr->hosts[server_key], buffer, write_length, 0);
- if (rc != MEMCACHED_SUCCESS)
- goto error;
-
- if ((sent_length= memcached_io_write(&ptr->hosts[server_key], value, value_length, 0)) == -1)
- {
- rc= MEMCACHED_WRITE_FAILURE;
- goto error;
- }
+ return MEMCACHED_WRITE_FAILURE;
if ((ptr->flags & MEM_BUFFER_REQUESTS) && verb == SET_OP)
to_write= 0;
else
to_write= 1;
- if ((sent_length= memcached_io_write(&ptr->hosts[server_key], "\r\n", 2, to_write)) == -1)
+ do
{
- rc= MEMCACHED_WRITE_FAILURE;
- goto error;
- }
+ rc[replicas]= memcached_do(&ptr->hosts[server_key], buffer, write_length, 0);
+
+ if (rc[replicas] != MEMCACHED_SUCCESS)
+ goto error;
- if (to_write == 0)
- return MEMCACHED_BUFFERED;
+ if ((sent_length= memcached_io_write(&ptr->hosts[server_key], value, value_length, 0)) == -1)
+ {
+ rc[replicas]= MEMCACHED_WRITE_FAILURE;
+ goto error;
+ }
- rc= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
+ if ((sent_length= memcached_io_write(&ptr->hosts[server_key], "\r\n", 2, to_write)) == -1)
+ {
+ rc[replicas]= MEMCACHED_WRITE_FAILURE;
+ goto error;
+ }
- if (rc == MEMCACHED_STORED)
- return MEMCACHED_SUCCESS;
- else
- return rc;
+ if (to_write == 0)
+ return MEMCACHED_BUFFERED;
+ else
+ rc[replicas]= memcached_response(&ptr->hosts[server_key], buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
+ /* On error we just jump to the next potential server */
error:
- memcached_io_reset(&ptr->hosts[server_key]);
+ if (replicas > 1 && ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT)
+ {
+ if (server_key == (ptr->number_of_hosts - 1))
+ server_key= 0;
+ else
+ server_key++;
+ }
+ } while ((++replicas) < ptr->number_of_replicas);
+
+ /* As long as one object gets stored, we count this as a success */
+ while (replicas--)
+ {
+ if (rc[replicas] == MEMCACHED_STORED)
+ return MEMCACHED_SUCCESS;
+ }
- return rc;
+ return rc[0];
}
memcached_return memcached_set(memcached_st *ptr, char *key, size_t key_length,
projects / awesomized / libmemcached / commitdiff
