Fixed mget_execute possibly failing into some non ending recursive call

[m6w6/libmemcached] / docs / memcached_get.pod

diff --git a/docs/memcached_get.pod b/docs/memcached_get.pod
old mode 100755 (executable)
new mode 100644 (file)
index 1cf0a60..db2c9b5
--- a/docs/memcached_get.pod
+++ b/docs/memcached_get.pod
@@ -1,6 +1,7 @@
 =head1 NAME
 
-memcached_get, memcached_mget, memcached_fetch
+memcached_get, memcached_mget, memcached_fetch, memcached_mget_execute,
+memcached_mget_execute_by_key - Get a value
 
 =head1 LIBRARY
 
@@ -16,40 +17,65 @@ C Client Library for memcached (libmemcached, -lmemcached)
                       memcached_return *error);
 
   char *memcached_get (memcached_st *ptr,
-                       char *key, size_t key_length,
+                       const char *key, size_t key_length,
                        size_t *value_length, 
                        uint32_t *flags,
                        memcached_return *error);
 
   memcached_return
   memcached_mget (memcached_st *ptr, 
-                  char **keys, size_t *key_length, 
-                  unsigned int number_of_keys);
+                  const char * const *keys, 
+                  const size_t *key_length, 
+                  size_t number_of_keys);
   char *
   memcached_get_by_key(memcached_st *ptr, 
-                       char *master_key, size_t master_key_length, 
-                       char *key, size_t key_length, 
+                       const char *master_key, size_t master_key_length, 
+                       const char *key, size_t key_length, 
                        size_t *value_length, 
                        uint32_t *flags,
                        memcached_return *error);
 
   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);
+                        const char *master_key, size_t master_key_length,
+                        const char * const *keys, 
+                        const size_t *key_length, 
+                        size_t number_of_keys);
 
   char *memcached_fetch (memcached_st *ptr,
                          char *key, size_t *key_length, 
                          size_t *value_length,
                          uint32_t *flags, 
                          memcached_return *error);
+
   memcached_return 
   memcached_fetch_execute(memcached_st *ptr, 
-                          unsigned int (*callback[])(memcached_st *ptr, memcached_result_st *result, void *context),
+                          memcached_return (*callback[])(memcached_st *ptr, memcached_result_st *result, void *context),
                           void *context,
                           unsigned int number_of_callbacks);
 
+
+  memcached_return
+  memcached_mget_execute(memcached_st *ptr,
+                         const char * const *keys,
+                         const size_t *key_length,
+                         size_t number_of_keys,
+                         memcached_execute_function *callback,
+                         void *context,
+                         unsigned int number_of_callbacks);
+
+  memcached_return 
+  memcached_mget_execute_by_key(memcached_st *ptr,
+                                const char *master_key,
+                                size_t master_key_length,
+                                const char * const *keys,
+                                const size_t *key_length,
+                                size_t number_of_keys,
+                                memcached_execute_function *callback,
+                                void *context,
+                                unsigned int number_of_callbacks);
+
+
 =head1 DESCRIPTION
 
 memcached_get() is used to fetch an individual value from the server. You
@@ -58,7 +84,8 @@ three pointer variables which will give you the state of the returned
 object.  A uint32_t pointer to contain whatever flags you stored with the value,
 a size_t pointer which will be filled with size of of the object, and a
 memcached_return pointer to hold any error. The object will be returned
-upon success and NULL will be returned on failure. 
+upon success and NULL will be returned on failure. Any object returned by
+memcached_get() must be released by the caller application. 
 
 memcached_mget() is used to select multiple keys at once. For multiple key
 operations it is always faster to use this function. This function always
@@ -77,7 +104,10 @@ three pointer variables which will give you the state of the returned
 object.  A uint32_t pointer to contain whatever flags you stored with the value,
 a size_t pointer which will be filled with size of of the object, and a
 memcached_return pointer to hold any error. The object will be returned
-upon success and NULL will be returned on failure. 
+upon success and NULL will be returned on failure. MEMCACHD_END is returned
+by the *error value when all objects that have been found are returned. 
+The final value upon MEMCACHED_END is null. Values returned by
+memcached_fetch() musted be free'ed by the caller.
 
 memcached_fetch_result() is used to return a memcached_result_st(3) structure 
 from a memcached server. The result object is forward compatible with changes
@@ -95,11 +125,27 @@ you supply the calling function. Currently only one value is being passed
 to each function call. In the future there will be an option to allow this
 to be an array.
 
+memcached_mget_execute() and memcached_mget_execute_by_key() is
+similar to memcached_mget(), but it may trigger the supplied callbacks
+with result sets while sending out the queries. If you try to perform
+a really large multiget with memcached_mget() you may encounter a
+deadlock in the OS kernel (we fail to write data to the socket because
+the input buffer is full). memcached_mget_execute() solves this
+problem by processing some of the results before continuing sending
+out requests. Please note that this function is only available in the
+binary protocol.
+
 memcached_get_by_key() and memcached_mget_by_key() behave in a similar nature
 as memcached_get() and memcached_mget(). The difference is that they take
 a master key that is used for determining which server an object was stored
 if key partitioning was used for storage.
 
+All of the above functions are not supported when the C<MEMCACHED_BEHAVIOR_USE_UDP>
+has been set. Executing any of these functions with this behavior on will result in 
+C<MEMCACHED_NOT_SUPPORTED> being returned or, for those functions which do not return
+a C<memcached_return>, the error function parameter will be set to 
+C<MEMCACHED_NOT_SUPPORTED>.
+
 =head1 RETURN
 
 All objects returned must be freed by the calling application.