On Tue, Feb 19, 2013 at 7:58 PM, Ralph Meijer <[email protected]> wrote: > On 2013-02-19 12:06, Dave Cridland wrote: >> >> >> On 19 Feb 2013 08:47, "Ashley Ward" <[email protected] >> <mailto:[email protected]>> wrote: >> > >> > >> > >> > On 18/02/2013 18:19, "Ralph Meijer" <[email protected] >> <mailto:[email protected]>> wrote: >> > >> > >On 2013-02-18 17:34, Kevin Smith wrote: >> > >> >> > >> Thoughts? >> > > >> > >Maybe this option is not very well suited for the case where there are >> > >potentially multiple publishers, as one of them going offline would >> > >result in the retraction of items published by others, too. >> > > >> > >I agree this should be described better. >> > >> > Maybe it would make more sense if purge_offline applied to the node >> owner >> > rather than the publisher? >> > >> >> Except that you can have multiple node owners, too. >> >> So seeing as I can think of use cases where multiple publishers and >> partial purges happen, I think we should be sending retractions for >> partial purges and purge notifications for full purges - both subject to >> the notify_retract option, of course. > > > Agreed. > > I'd like to reiterate that this particular feature is probably useful only > for some very specific use cases. The changelog that mentions the feature > being added mentions 'extended presence'. This more or less implies PEP > nodes with a single publisher/owner and a tight availability presence > coupling. > > Having "partial purges" might be quite an expensive operation with many > persisted items and I don't really feel like addressing that at this point > (e.g. with new protocol). > > Even though I know that at least ejabberd's pubsub support has this feature, > I am not aware of any applications using it. > > We can either clarify the intended use while mentioning some potential > issues mentioned in this thread, or deprecate the feature altogether.
Thanks. The reason this came up is that someone /is/ using the feature :) So, my follow-up question is whether this should be triggered when a user goes offline (no remaning presence) or a session becomes unavailable. That is, if you have multiple resources, do you get partial purges each time a resource goes offline, or do you just get a complete purge once all resources are offline (I would assume the latter, given earlier discussions about 'just one publisher'). /K
