Connect to your memcached host. (AWS elasticache is memcached)

telnet foohost23.cs2631.0001.euw1.cache.amazonaws.com 11211 

Growing Rails Applications in Practice

Check out our e-book. Learn to structure large Ruby on Rails codebases with the tools you already know and love.

• Introduce design conventions for controllers and user-facing models
• Create a system for growth
• Build applications to last

Read more Show archive.org snapshot

Once you're connected, find out which 'slabs' exist within the cache:

stats items
STAT items:1:number 3550
STAT items:1:age 5166393
STAT items:1:evicted 0
STAT items:1:evicted_nonzero 0
STAT items:1:evicted_time 0
STAT items:1:outofmemory 0
STAT items:1:tailrepairs 0
STAT items:1:reclaimed 0
STAT items:2:number 144886
STAT items:2:age 1375536
STAT items:2:evicted 0
STAT items:2:evicted_nonzero 0
STAT items:2:evicted_time 0
STAT items:2:outofmemory 0
STAT items:2:tailrepairs 0
STAT items:2:reclaimed 1638
STAT items:3:number 2628952
STAT items:3:age 232524
STAT items:3:evicted 0
STAT items:3:evicted_nonzero 0
STAT items:3:evicted_time 0
STAT items:3:outofmemory 0
STAT items:3:tailrepairs 0
STAT items:3:reclaimed 151110
...

The number after items: shows the respective slab.
You can retrieve the keys stored within this container using stats cachedump <slab> <limit>:

stats cachedump 1 5
ITEM foo100:Class|last_id [6 b; 1342195946 s]
ITEM foo106:Class|last_id [7 b; 1342195946 s]
ITEM foo:Class|last_id [7 b; 1342195946 s]
ITEM foo106:Class|lock [9 b; 1373030893 s]
ITEM foo100:Class|lock [8 b; 1373030581 s]