(PECL memcache >= 2.0.0)
Memcache::getExtendedStats — Get statistics from all servers in pool
$type
   [, int $slabid
   [, int $limit = 100
  ]]] )
   Memcache::getExtendedStats() returns a two-dimensional
   associative array with server statistics. Array keys correspond to 
   host:port of server and values contain the individual server statistics.
   A failed server will have its corresponding entry set to FALSE.
   You can also use the memcache_get_extended_stats() function.
  
Note:
This function has been added to Memcache version 2.0.0.
typeThe type of statistics to fetch. Valid values are {reset, malloc, maps, cachedump, slabs, items, sizes}. According to the memcached protocol spec these additional arguments "are subject to change for the convenience of memcache developers".
slabid
       Used in conjunction with type set to 
       cachedump to identify the slab to dump from. The cachedump
       command ties up the server and is strictly to be used for 
       debugging purposes.
      
limit
       Used in conjunction with type set to 
       cachedump to limit the number of entries to dump.
      
The cachedump stat type has been removed from the memcached daemon due to security reasons.
   Returns a two-dimensional associative array of server statistics or FALSE
   on failure.
  
Example #1 Memcache::getExtendedStats() example
<?php
    $memcache_obj = new Memcache;
    $memcache_obj->addServer('memcache_host', 11211);
    $memcache_obj->addServer('failed_host', 11211);
    
    $stats = $memcache_obj->getExtendedStats();
    print_r($stats);
?>
The above example will output:
Array
(
    [memcache_host:11211] => Array
        (
            [pid] => 3756
            [uptime] => 603011
            [time] => 1133810435
            [version] => 1.1.12
            [rusage_user] => 0.451931
            [rusage_system] => 0.634903
            [curr_items] => 2483
            [total_items] => 3079
            [bytes] => 2718136
            [curr_connections] => 2
            [total_connections] => 807
            [connection_structures] => 13
            [cmd_get] => 9748
            [cmd_set] => 3096
            [get_hits] => 5976
            [get_misses] => 3772
            [bytes_read] => 3448968
            [bytes_written] => 2318883
            [limit_maxbytes] => 33554432
        )
    [failed_host:11211] => false
)