Agreed! Let's move forward with kborchers document and think about the same problem guys.

Sorry, I didn't notice that.

"The measure of a man is what he does with power" - Plato
Volenti Nihil Difficile

On Thursday, September 13, 2012 at 11:10 AM, Kris Borchers wrote:

Should these documents be merged?

On Sep 13, 2012, at 9:08 AM, Bruno Oliveira <> wrote:

Hi my friends, we have a great discussion here and we can't miss it, for this reason I've created this document feel free to tweak, change, delete sections as needed.

I'd like to have UUID generation details there, in this way we don't lose it. Probably the server will handle this UUID generation, but assuming that it will affect all platforms would be nice to start a minimum description.

"The measure of a man is what he does with power" - Plato
Volenti Nihil Difficile

On Wednesday, September 12, 2012 at 10:39 AM, Marko Strukelj wrote:

Hey Kris,

On 9/11/12 4:20 PM, Kris Borchers wrote:
I have been thinking about this a bit lately and am also hoping to
people's thoughts on whether or not this may be overkill. The
reason I
say that is that really the only reason you would need such a
unique id
is if there will be a chance of something else (another client,
etc.) generating an id for a piece of data that would conflict with
one. What I was thinking though is that is only an issue at sync
As long as you know the id is unique in the client, and the status
that piece of data (new, modified, removed), then at sync time, you
rectify those id's that are out of sync with what is generated at
server and you have one point of id generation.

I've always been a fan of server-side ID generation, just because I
always tend to think about malicious or badly-written clients. It's
possible for someone to pollute the ID pool such that a real ID that
later client generates for a new object is rejected as a duplicate -
so we'd need to account for that possibility and have the UUID
regenerated in that case. Edge case, to be sure, but those are often
where the problems lie.

ID generation only happens upon create operation. And it's a UNIQUE constraint on relational DB that can be used, or a simple EXISTS check to see if an entity with the ID exists already. And if it does, that's an error that cancels the operation. So, if you can guess a UUID about to be produced by someone else, and use it before they do (sync your entity to the server, before they do theirs) you can cause theirs to fail to sync - be rejected.

I can imagine such a denial of service attack possible if there is an issue with UUID generator used.

I can also imagine a duplicate UUIDs generated if there is an issue with UUID generator or the way it is used.

Adding a autorecovery that would automatically regenerate UUIDs on the client and perform updates would add to reliability, but adds bloat.

It's an interesting issue for sure.

That said, as long as we're careful I'm fine with client-gen'ed

+0 from me.


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