Re: load time regression: Re: commit: Change Record UUID's

>
>> I can't claim to understand what's going on here, but how about using
>> the timer when the document is loaded (and/or saved?) to generate a
>> document-unique ID, and then appending a counter value to this for
>> change records?
>
> Counter will not work in whatever shape and form: think of two users
> running two instances of AW on two different computers editing the same
> document via the collab features, and hence generating change records.
> It must be possible to order the change records in absolute (i.e., not
> relative) manner to create a single change record queue, and that
> requires that the change record id carries a reasonably accurate
> timestamp.
>

I'm not so sure about that. I think that after synchronization we actually
do want counters running on each users document. The counters will inform
other members of the abicollab network if there has been a clash of edits
due to network latency.

ie if Alice and Bob are both editting the same document then there was no
latency issues something like this would happen:

Alice Bob
counter Counter
1 1 (initially)
2 1 (Alice edits)
2 > 2 (Alice's edit is tranmitted to Bob and is applied)
3 2 (Alice edits again)
3 > 3 (Transmitted to Bob)
3 4 (Bob edits)
4 < 4 (Transmitted to Alice)
4 5 (Bob Edits again)
5 < 5 (Transmitted to Alice)
6 5 (Alice edits)
6 > 6 (Transmitted to Bob)

OK Now suppose we have a latency issue....

7 7 (Alice and Bob both edit before seeing the other)
7? <> 7? (When the packets arrive they see counters equal
                         or greater than themselves. So they know they need
                         to do some sort of conflict resolution.)

I talk about how to solve this sort of problem in the GOCollab document.

We may also need timestamps but they need to be very accurate.

Martin

> We can, of course #if 0 the bit in 2.4.x; in general we might decide to
> only generate proper uuid's for change records when AW is running in
> collaborative mode, using something like PD_Document::isCollaborative().
>
> Tomas
>
>
> ___________________________________________________________
> How much free photo storage do you get? Store your holiday
> snaps for FREE with Yahoo! Photos http://uk.photos.yahoo.com
>
>
Received on Mon Oct 24 16:46:50 2005