0. 特别注意：

通过cachedump命令只能获取1M的数据，无法获取更多的数据。

1. 命令行来查看memcache的key及取值

1. stats slabs 查看有哪些slab

   STAT 18:chunk_size 4544
   STAT 18:chunks_per_page 230
   STAT 18:total_pages 1
   STAT 18:total_chunks 230
   STAT 18:used_chunks 0
   STAT 18:free_chunks 7
   STAT 18:free_chunks_end 223
   STAT 18:mem_requested 18446744073709551411
   STAT 18:get_hits 777
   STAT 18:cmd_set 103
   STAT 18:delete_hits 0
   STAT 18:incr_hits 0
   STAT 18:decr_hits 0
   STAT 18:cas_hits 0
   STAT 18:cas_badval 0

2. stats cachedump slab_id limit

   将slab为slab_id的数据展示出来。 limit是展示的个数，如果取值为0， 则不作限制（其实是限制了1m）

http://blog.elijaa.org/2010/12/24/understanding-memcached-stats-cachedump-command/
http://blog.elijaa.org/2010/05/21/memcached-telnet-command-summary/#slabs_stats

2. php代码来获取

<?php
$mcobj = new Memcache();
$mcobj->addServer('xxx',9150);

$to_mcobj = new Memcache();
$to_mcobj->addServer('xxx', 21212);

$allSlabs = $mcobj->getExtendedStats('slabs');
$items    = $mcobj->getExtendedStats('items');
foreach ($allSlabs as $server => $slabs) {
    foreach ($slabs as $slabId => $slabMeta) {
        $cdump = $mcobj->getExtendedStats('cachedump', (int)$slabId, 0);
        foreach ($cdump as $keys => $vals) {
            foreach ((array)$vals as $k => $v) {
                $real_val = $mcobj->get($k);
                $set_res = $to_mcobj->set($k, $real_val);
                error_log('|slabId='.$slabId.'set--'.'|key='.$k.'|val='.json_encode($real_val).'|res='.$set_res."\n",3,'/tmp/yk.log');
            }
        }
   }
                                                                                            }