consistent hashing: in Perl, standards

Alex Stapleton alexs at
Wed Apr 25 12:27:02 UTC 2007

Is this meant to be a thread about algorithms or a thread about  
implementations of algorithms?

Personally I think we should be working towards having a standard C  
implementation of a memcached client that can be linked in as a  
library for other languages. (I've done some work on this already  
actually...)  C afterall is the LCD for pretty much every language we  
care about right? Which means I think we should simply be hacking on  
top of Ketama or a fork or start from scratch :) Is there some  
advantage to having lots of client implementations in various  
languages that I'm not aware of?

Alex Stapleton
alexs at
T: 0207 0700 956

On 25 Apr 2007, at 03:36, Brad Fitzpatrick wrote:

> Back in August I posted some consistent hashing code.  I finally got
> around to putting it into a Perl library recently:
> But with some of the alternatives springing up, it might be a good  
> time to
> discuss some standard consistent hashing strategies, for inter- 
> language
> interop (when sharing the same set of memcached server using different
> client libraries/languages), in the same way we all agreed to use
> certain bits out of crc32 back in the day.
> And let me predeclare that I don't claim my implementation to be the
> best... it might have bugs, or there might be better ways to do stuff.
> But it was my testbed for testing how things distributed on  
> failures, and
> I made sure it was fast (it precomputes the node selection for 1024  
> points
> on the circle, so the common case is an array lookup on, say,
> crc32($your_key) % 1024, rather than doing the full lookup every  
> time...)
> Anybody care to lead this discussion?  I just wanted to kick-start  
> it. :)
> - Brad

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