MEMCACHED_STAT

NAME

memcached_stat - libmemcached Documentation

Get memcached statistics

SYNOPSIS

#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)

Param server

pointer to the memcached_instance_st being stat'ed

Param key

the current key

Param key_length

the length of the key without any terminating zero

Param value

the value read

Param value_length

the length of the value without any terminating zero

Param context

pointer to the user supplied context

Returns

memcached_return_t indicating success

memcached_stat_st *memcached_stat(memcached_st *ptr, char *args,
memcached_return_t *error)

Parameters

	•		ptr -- pointer to an initialized memcached_st struct
	•		args -- particular state object to query
	•		error -- pointer to memcached_return_t indicating success

Returns

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)

Parameters

	•		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

Returns

memcached_return_t indicating success

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

Parameters

	•		ptr -- pointer to initialized memcached_st struct
	•		stat -- pointer to initialized memcached_stat_st struct
	•		key -- the statistic to query
	•		error -- pointer to memcached_return_t indicating success

Returns

string value of the statistic

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

Parameters

	•		ptr -- pointer to initialized memcached_st struct
	•		stat -- pointer to initialized memcached_stat_st struct
	•		error -- pointer to memcached_return_t indicating success

Returns

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)

Parameters

	•		ptr -- pointer to initialized memcached_st struct
	•		args -- particular state object to query
	•		func -- memcached_stat_fn callback
	•		context -- pointer to user supplied context

Returns

memcached_return_t indication success

DESCRIPTION

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.

RETURN VALUE

Varies, see particular functions.

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

SEE ALSO

memcached(1) libmemcached(3) memcached_strerror(3)