PHP Manual: Get statistics of the server

arrayfalse Memcache::getStats(string $type = ?, int $slabid = ?, int $limit = 100)

arrayfalse memcache_get_stats(
    Memcache $memcache,
    string $type = ?,
    int $slabid = ?,
    int $limit = 100
)

Memcache::getStats returns an associative array with server's statistics. Array keys correspond to stats parameters and values to parameter's values.

type: The 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.

Returns an associative array of server statistics or false on failure.

Memcache::getStats