Working with statistical information from a server

Get memcached statistics


#include <libmemcached/memcached.h>
Compile and link with -lmemcached
typedef struct memcached_stat_st memcached_stat_st
typedef memcached_return_t (*memcached_stat_fn)(const memcached_instance_st *server, const char *key, size_t key_length, const char *value, size_t value_length, void *context)
  • server -- pointer to the memcached_instance_st being stat'ed
  • key -- the current key
  • key_length -- the length of the key without any terminating zero
  • value -- the value read
  • value_length -- the length of the value without any terminating zero
  • context -- pointer to the user supplied context

memcached_return_t indicating success

memcached_stat_st *memcached_stat(memcached_st *ptr, char *args, memcached_return_t *error)
  • ptr -- pointer to an initialized memcached_st struct
  • args -- particular state object to query
  • error -- pointer to memcached_return_t indicating success

array of memcached_stat_st objects for all available servers

memcached_return_t memcached_stat_servername(memcached_stat_st *stat, char *args, const char *hostname, in_port_t port)
  • stat -- pointer to a memcached_stat_st struct to fill
  • args -- particular state object to query
  • hostname -- the hostname or IP address of the server to stat
  • port -- the port of the server to stat

memcached_return_t indicating success

char *memcached_stat_get_value(memcached_st *ptr, memcached_stat_st *stat, const char *key, memcached_return_t *error)

string value of the statistic

char **memcached_stat_get_keys(memcached_st *ptr, memcached_stat_st *stat, memcached_return_t *error)

array of default keys probably available in the statistics

memcached_return_t memcached_stat_execute(memcached_st *ptr, const char *args, memcached_stat_fn func, void *context)
  • ptr -- pointer to initialized memcached_st struct
  • args -- particular state object to query
  • func -- memcached_stat_fn callback
  • context -- pointer to user supplied context

memcached_return_t indication success


libmemcached has the ability to query a memcached(1) server (or collection of servers) for their current state. Queries to find state return a memcached_stat_st structure. You are responsible for freeing this structure. While it is possible to access the structure directly it is not advisable. memcached_stat_get_value() has been provided to query the structure.

memcached_stat_execute() uses the servers found in memcached_stat_st and executes a "stat" command on each server. args is an optional argument that can be passed in to modify the behavior of "stats". You will need to supply a callback function that will be supplied each pair of values returned by the memcached server.

memcached_stat() fetches an array of memcached_stat_st structures containing the state of all available memcached servers. The return value must be freed by the calling application. If called with the MEMCACHED_BEHAVIOR_USE_UDP behavior set, a NULL value is returned and the error parameter is set to MEMCACHED_NOT_SUPPORTED.

memcached_stat_servername() can be used standalone without a memcached_st to obtain the state of a particular server. "args" is used to define a particular state object (a list of these are not provided for by either the memcached_stat_get_keys() call nor are they defined in the memcached protocol). You must specify the hostname and port of the server you want to obtain information on.

memcached_stat_get_value() returns the value of a particular state key. You specify the key you wish to obtain. The key must be null terminated.

memcached_stat_get_keys() returns a list of keys that the server has state objects on. You are responsible for freeing this list.

A command line tool, memstat, is provided so that you do not have to write an application to do this.


Varies, see particular functions.

Any method returning a memcached_stat_st expects you to free the memory allocated for it.