[Standards] mobile optimizations

Pedro Melo melo at simplicidade.org
Thu Feb 28 10:54:03 UTC 2008


On Feb 27, 2008, at 9:19 PM, Alexander Gnauck wrote:
> Fabio Forno wrote:
>> I like this one, since it always has a backup when no sinchronization
>> is needed. Moreover the server can store only a window of changes,  
>> and
>> send the whole roster if the last known by the client is too old
> +1, I don't think we want to keep all roster revisions from the  
> beginning. If servers will give us such a option this is great, but  
> I don't think it should be required.
> For "normal" usage about 100 revisions should be fine.

well, in practical terms, if we store a generation_id on each roster  
entry, that gets updated for each entry modification, and assuming a  
SQL-style roster store, keeping changes "forever" costs you the size  
of the generation_id field per entry, and you can just add a WHERE  
generation_id > SENT_BY_CLIENT to the usual SQL.

So I would vote for a generation/version-style solution.

Best regards,
Pedro Melo
Blog: http://www.simplicidade.org/notes/
XMPP ID: melo at simplicidade.org

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