From: Eric Hodel <drbrain@...7.net>
Date: 2008-02-23T05:07:22+09:00
Subject: Re: Memcached: Dealing with unknown keys

On Feb 14, 2008, at 14:33 PM, Tony Garcia wrote:
> Ben Bleything wrote:
>> On Fri, Feb 15, 2008, Tony Garcia wrote:
>>> I need to pass information (for example, an email address) based  
>>> on user
>>> name from a rails application to a disconnected ruby process  
>>> through the
>>> cache. The external process has no way to know what users are being
>>> passed to it. I had wanted to use the user name as the key, but it  
>>> seems
>>> that I can't find the values of current keys in the cache - at  
>>> least not
>>> with memcache-client.
>>
>> It sounds like you're trying to use the cache as a message queue,  
>> when
>> you should probably be using both in tandem... that is, store user  
>> data
>> in the cache, but send messages along the queue with the user name,  
>> so
>> the disconnected process can look it up in the cache.
>
> Only the username, email address, and a code are being stored - there
> are no messages or other items that need to be passed along.
>
>> Caching in general (and memcache in particular) are intended to  
>> speed up
>> slow data access, not to act as data repositories.
>
> Granted - and I am using memcache as a queue in this case. I've done a
> lot of looking and can't find much else that will do what I need - and
> Joyent has memcache already installed.
>
> If anyone has a better suggestion, I'd love to hear it. This is the  
> best
> I've been able to figure out on my own.

memcached is the wrong tool for this purpose.  It is intended to be a  
cache for some other persistent storage service.