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Re: Digest for [email protected] - 8 Messages in 4 Topics

Posted by Fei Wang 
武汉大学z

Sent from my iPhone

On Aug 28, 2010, at 12:48 PM, memcached+noreply@googlegroups.com wrote:

> Today's Topic Summary
> Group: http://groups.google.com/group/memcached/topics
>
> memcached permissions [4 Updates]
> Surge 2010 Early Registration ends Tuesday! [1 Update]
> Consistent hashing in PHP and Java [2 Updates]
> Help Needed - Rails Cache - Time Based [1 Update]
> Topic: memcached permissions
> KaiGai Kohei <[email protected]> Aug 27 05:45PM +0900 ^
>
> BTW, how about getting inclusion of this patch?
>
> (2010/08/16 14:38), KaiGai Kohei wrote:
>
> --
> KaiGai Kohei <[email protected]>
>
>
> dormando <[email protected]> Aug 27 02:02AM -0700 ^
>
> We're still working on merging down 1.6... but if this exists outside as
> an engine nothing of us blocks you from using it for now.
>
> I sort of wonder a little about outright pulling it into the tree, since
> that implies we have to maintain it.
>
> On Fri, 27 Aug 2010, KaiGai Kohei wrote:
>
>
>
> KaiGai <[email protected]> Aug 27 04:57PM -0700 ^
>
> Sorry for the confusion.
> I intended to talk to maintainer of the standard security policy in
> SELinux.
>
> It is my job to maintain the selinux_engine.so module. :-)
>
> Thanks,
>
>
>
> dormando <[email protected]> Aug 27 04:59PM -0700 ^
>
> Ahhah, thanks :)
>
> Was uh, scared for a moment the that initial thread had been lost in time.
>
> On Fri, 27 Aug 2010, KaiGai wrote:
>
>
>
> Topic: Surge 2010 Early Registration ends Tuesday!
> Jason Dixon <[email protected]> Aug 27 03:33PM -0400 ^
>
> Early Bird Registration for Surge Scalability Conference 2010 ends next
> Tuesday, August 31. We have a killer lineup of speakers and architects
> from across the Internet. Listen to experts talk about the newest
> methods and technologies for scaling your Web presence.
>
> http://omniti.com/surge/2010/register
>
> This year's event is all about the challenges faced (and overcome) in
> real-life production architectures. Meet the engineering talent from
> some of the best and brightest throughout the Internet:
>
> John Allspaw, Etsy
> Theo Schlossnagle, OmniTI
> Bryan Cantrill, Joyent
> Rasmus Lerdorf, creator of PHP
> Tom Cook, Facebook
> Benjamin Black, fast_ip
> Christopher Brown, Opscode
> Artur Bergman, Wikia
> Baron Schwartz, Percona
> Paul Querna, Cloudkick
>
> Surge 2010 takes place at the Tremont Grand Historic Venue on Sept 30
> and Oct 1, 2010 in Baltimore, MD. Register NOW for the Early Bird
> discount and guarantee your seat to this year's event!
>
>
> --
> Jason Dixon
> OmniTI Computer Consulting, Inc.
> jdixon@omniti.com
> 443.325.1357 x.241
>
>
> Topic: Consistent hashing in PHP and Java
> Vicente Aguilar <[email protected]> Aug 27 09:19AM +0200 ^
>
> Hi
>
> At work we're setting up a multi-layered cluster with a 1st line of web/proxy/cache servers (nginx+memcached) and several layers of PHP-FPM and Tomcat application servers. At the moment we're using memcached just to cache raw HTML pages, not serialized objects: upon a request nginx checks if that URL (key) is on memcached and then serves it, else it proxies the request to the appropriate app server which serves it and saves it to memcached. Pretty basic memcached usage.
>
> The problem is that we can't get the PHP, Java and nginx implementations to work together, the PHP and Java consistent hashing algorithms don't seem to match.
>
> We're using:
>
> - nginx: http://wiki.nginx.org/NginxHttpUpstreamConsistentHash
> - PHP: PECL:memcache http://pecl.php.net/package/memcache
> - Java: spymemcached http://code.google.com/p/spymemcached/
>
> Both the nginx and PHP implementations match, any HTML representation saved by PHP is retrieved by nginx from the same memcached server; but spymemcached's implementation seems to be different and with 2 memcached server only matches 50% of the time, so it's a completely different algorithm and the matches are random. We're using the nginx patch and PECL:memcached with their default configuration, and as for spymemcached we've tried the NATIVE_HASH, CRC32_HASH and KETAMA_HASH algorithms but none of them matches nginx' and PHP's hashing.
>
> Anybody else here is using memcached in Java and PHP and got them to work together? I've searched the list and this question has been raised several times but haven't find any definitive answer, just the obvious "different libraries may use different hashing implementations". We don't mind switching to other libraries.
>
> Thanks in advance.
>
> Regards
>
> --
> Vicente Aguilar <[email protected]> | http://www.bisente.com
>
>
> Matt Ingenthron <[email protected]> Aug 27 10:45AM -0700 ^
>
> Hi Vicente,
>
> Vicente Aguilar wrote:
>
> > The problem is that we can't get the PHP, Java and nginx
> > implementations to work together, the PHP and Java consistent hashing
> > algorithms don't seem to match.
>
> We (Dustin Sallings and Steve Yen mainly) did a lot of testing in
> spymemcached to ensure the hashing was the same between it and libketama
> in the most recent release. There is a very large test of these in
> spymemcached. In the process a bug was found and fixed, but it was a
> very minor bug.
>
> It was compared to what libmemcached is doing with it's hashing and it's
> been well verified. More below...
>
> > raised several times but haven't find any definitive answer, just the
> > obvious "different libraries may use different hashing
> > implementations". We don't mind switching to other libraries.
>
> Assuming you're using the latest spymemcached (which was released some
> time ago) and a recent pecl/memcached, at least those two should work
> together. The PHP level wasn't, but the libmemcached ketama and
> spymemcached ketama are well tested.
>
> With only two servers, nearly anything could make it be 50% off but it
> almost sounds like one client is seeing one of the servers as down. In
> a ketama world, that'd mean put all of it on the remaining up servers
> (the other one in your case).
>
> The only other thing to be careful with is perhaps the key (which seems
> to be a URL in your case?) is getting truncated or treated differently
> in different places?
>
> Sorry I don't have any clear answers here, but I can say it's been
> tested and SHOULD work.
>
> - Matt
>
>
> Topic: Help Needed - Rails Cache - Time Based
> moses wejuli <[email protected]> Aug 27 11:05AM +0100 ^
>
> thanks but i'm unavailable at the moment.
>
>
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