[Standards] mobile optimizations
gnauck at ag-software.de
Wed Feb 27 18:19:13 UTC 2008
Dave Cridland wrote:
> 2) Client says "I have the roster as of this point in time". Server says
> "Here's all the changes since then.".
> This is obviously the best option in terms of efficiency, but it, too,
> has problems. The key issue is that roster entries won't die - instead,
> they'll be maintained along with a timestamp when deleted, in order that
> the server can tell a client it's gone.
yes I think the logic on the server will get very complicated. Util I
have a mutual subscription to a contact the server updates the roster
item several times(subscription=none,from or to,both +ask). This will be
~5 versions until the subscription is mutual.
> I also have a fondness for modified strictly increasing timestamps, but
> implementors need to appreciate that computer clocks go backwards, so
> they need to remember to handle odd cases like that by "letting time
> catch up" - just using a few ms later than the last timestamp until the
> real time is greater than the last timestamp.
for this reason I would prefer a versioning of the roster, so I client
can just tell the server I have version 235241 of the roster, let me
know if this is the current roster or send me the changes otherwise.
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