Cache::Memcached::Lock

[Cahill, Earl]

Sure, but hopefully, it being able to handle timeouts and the like
properly would ease some of those concerns.  The two or three days I
have been using mine have treated me well :)

I think some of the concern comes from Cache being in the name of
Cache::Memcache.  I guess my question is, when can you trust Memcached?
Like, can I trust the ttl?  Is add really atomic?  If I set x=y, do I
get x=y back?  If yes to those three things, then Memcached seems a good
candidate for my project.  If not?  Well, then maybe I shouldn't be
using Memcached for my other projects.  I don't really want data to
randomly change or disappear.  But in my experience, it doesn't.

I really like that Memcached is simply a fast, potentially big,
distributed hash.  If I can build something that I find useful around
it, something that maybe stretches it a little, all the better.  If I
find the stretching to be a touch painful, then I can report my findings
and try to contribute back to Memcached, or if worse comes to worse,
just use something else.

Some concerns seem a touch FUD-ish.

Earl

-----Original Message-----
From: Larry Leszczynski [mailto:larryl at emailplus.org] 
Sent: Monday, September 26, 2005 6:31 PM
To: Cahill, Earl
Cc: Perrin Harkins; memcached at lists.danga.com
Subject: RE: Cache::Memcached::Lock

Hi Earl -

> > I'm sure memcached would be fast at this, but I wonder if it's a
good 
> > idea to store locks in a cache.  Maybe a simple MySQL-based approach

> > would be safer.
> >
> > - Perrin
> 
> Yeah, I can buy that.  I can also buy that memcached on our system has

> been live for nearly six months, has yet to have a problem, has 
> 41,173,166 things currently cached across three boxes, and has handled

> over 120 requests per second per box during that time.  So yeah, it is
a 
> simple cache thing, but I don't think I would have much of a problem 
> relying on it.

I hope I don't mis-speak on behalf of Perrin, but I got the impression 
that his point was that it's not an issue of whether memcache was 
reliable/fast enough, but rather that it would be A Bad Thing if your
lock 
item got flushed or expired from the cache before the lock had really
been 
released...


Larry