MEMCACHED_STAT(3)

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)