get all keys set in memcached

If you have PHP & PHP-memcached installed, you can run

$ php -r '$c = new Memcached(); $c->addServer("localhost", 11211); var_dump( $c->getAllKeys() );'

Found a way, thanks to the link here (with the original google group discussion here)

First, Telnet to your server:

telnet 127.0.0.1 11211

Next, list the items to get the slab ids:

stats items
STAT items:3:number 1
STAT items:3:age 498
STAT items:22:number 1
STAT items:22:age 498
END

The first number after ‘items’ is the slab id. Request a cache dump for each slab id, with a limit for the max number of keys to dump:

stats cachedump 3 100
ITEM views.decorators.cache.cache_header..cc7d9 [6 b; 1256056128 s]
END

stats cachedump 22 100
ITEM views.decorators.cache.cache_page..8427e [7736 b; 1256056128 s]
END

memdump

There is a memcdump (sometimes memdump) command for that (part of libmemcached-tools), e.g.:

memcdump --servers=localhost

which will return all the keys.

---

memcached-tool

In the recent version of memcached there is also memcached-tool command, e.g.

memcached-tool localhost:11211 dump | less

which dumps all keys and values.

See also:

• What's the simplest way to get a dump of all memcached keys into a file?
• How do I view the data in memcache?

Base on @mu 無 answer here. I've written a cache dump script.

The script dumps all the content of a memcached server. It's tested with Ubuntu 12.04 and a localhost memcached, so your milage may vary.

#!/usr/bin/env bash

echo 'stats items'  \
| nc localhost 11211  \
| grep -oe ':[0-9]*:'  \
| grep -oe '[0-9]*'  \
| sort  \
| uniq  \
| xargs -L1 -I{} bash -c 'echo "stats cachedump {} 1000" | nc localhost 11211'

What it does, it goes through all the cache slabs and print 1000 entries of each.

Please be aware of certain limits of this script i.e. it may not scale for a 5GB cache server for example. But it's useful for debugging purposes on a local machine.