[Standards] Unread syncing

Christian Schudt christian.schudt at gmx.de
Fri Dec 2 14:35:45 UTC 2016


> Except that they’re not chat messages, so won’t be stored, and if they were you’d be potentially up to doubling the size of your archive (I guess adding a quarter to, on average) as you fill it with read markers - unless you want to customise the MAM service to understand unread state, in which case what have you gained?
 
As I read this, I was suprised, that MAM would only store chat messages. But it turns out MAM allows to store "normal" and "additional non-conversation messages" as per § 5.1.1.


> If you log on, your client does a complete synchronisation of all history from the (modified to include non-chat history for read markers) archive to local storage, and then processes the stanzas it will be able to see which contacts have unread messages and how many, yes. Having to do a full history download is clearly not tenable in the general case.

Are we talking about "read by user", or "read by resource"?

If it's "read by user", a client may receive zero unread messages and therefore not updating its local history, because the messages have already been read by another client (of the same user of course).
In that case, it's desirable to do a full history download anyway (not a full one, but only since the last download).
If it would only download the unread messages, the client would miss the messages, which have already been read on another device, resulting in an incomplete local history presentation.

If it's "read by resource", then you want MAM to manage which messages have been read by which resource?

-- Christian


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