[jdev] The future of Jabber/XMPP?

Dave Cridland dave at cridland.net
Thu Aug 26 11:47:57 CDT 2010

On Thu Aug 26 15:41:29 2010, Evgeniy Khramtsov wrote:
> 27.08.2010 00:16, Stephen Pendleton wrote:
>> I agree, PEP support isn't so great on the major server platforms.  
>> For
>> example Openfire's implementation has a memory leak. I think PEP  
>> is one
>> differentiating factor for XMPP. It would be nice to have solid,  
>> dependable
>> support in all the major platforms for it.
> Lots of bugs in PEP server implementations are because the XEP  
> itself is written poorly. It doesn't scale: the idea of keeping  
> resources and features of every user from every server on the  
> planet is completely insane. Don't be surprised if you see memory  
> leaks - they are by design :)

Well, I agree it's pretty easy to "leak" subscriptions (we[1] do,  
sometimes, if we never see an unavailable from a resource). That's  
our bug, and we'll be sorting that one out soon. Otherwise I don't  
think there's anything that inherently has a leak associated with it  
- even including the fact you gradually learn about every feature of  
every client, it's simply not that big a deal.

Honestly, I don't find PEP too much of a pain - it does have a memory  
cost, but it's really not astronomical, and the benefits are very  
nice for clients and users. We did try turning it off on one large  
site briefly (we had to first code in the off-switch), but it made  
sufficiently little difference to performance and memory that we  
re-enabled it. That site has somewehere approaching 80,000 PEP nodes,  

But the lack of PEP on many servers *is* causing us indirect  
problems, because services which'd really benefit from PEP  
(Buddycloud springs to mind, but there are others) don't use it at  
all because it's not available in so many places. I'd love to see a  
lot more PEP around, and I think the community as a whole would  
benefit enormously.


1. That's Isode M-Link, in case you wonder.
2. It's tricky to give an exact figure, but there's around 80,700  
pubsub nodes in total, but that includes around 3,000 MUC rooms.
Dave Cridland - mailto:dave at cridland.net - xmpp:dwd at dave.cridland.net
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