concerning server list management, connection pooling

Ofer Nave ofer at
Fri Jan 12 22:55:29 UTC 2007

I've known about memcached for a while, but only recently starting
researching it for potential implementation within my company.  I love the
architecture, but there are two specific issues that concern me that I
haven't heard have been solved yet:


1)       modifying the server list (to add a new memcached server, for
instance) destroys the key -> server mapping. the equivalent of a

2)       connection pooling


I realize both of these are not new issues to anyone on the list.  I've
tried skimming the archives to glean some insight from past discussions.  I
found a thread
( that
referenced a research paper about consistent hashing.  I also found a post
by Brad
( that
talks about the 'server list propagation' problem potentially being solved
by running a set of trackers and using virtual buckets.


Unfortunately, I can't find anything in the memcached docs themselves (at
danga/memcached/, and in the docs of the PHP and CPAN modules) addressing
these issues, or covering the use of trackers and virtual buckets, so I
suspect that while clever individuals may have come up with various
solutions, none of them have made it into the code.


So, my questions are as follows:


1)       What's the current consensus (or nearest to) on the list as to the
best strategies for these two issues?  (For the sake of context, assume an
apache environment with mod_perl or mod_php).

2)       Are there any working implementations of these solutions, either as
part of the client libraries, or as additional tools (one of the posts
mentioned creating a memcached admin tool)?

3)       If not, can I help?  I'm strongest with Perl, but can hack PHP if
need be, and I'm likely to need both clients at my work.  I'm also learning
Python, so I'm up for a good limited-scope project.. I can write good code,
but I have zero experience with memcached to date.  So while I'm happy to
help, I don't think I should be deciding what to implement, or how.



-------------- next part --------------
An HTML attachment was scrubbed...

More information about the memcached mailing list