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From Randall Leeds <randall.le...@gmail.com>
Subject Re: Unique instance IDs?
Date Tue, 13 Dec 2011 04:03:40 GMT
On Mon, Dec 12, 2011 at 19:31, Adam Kocoloski <kocolosk@apache.org> wrote:
> On Dec 12, 2011, at 10:26 PM, Paul Davis wrote:
>
>>> * Merkle trees are great for two-way synchronization, but it's not immediately
clear to me how you'd use them to bootstrap a single source -> target replication.  I
might just be missing a straightforward extension of the tech here.
>>
>> This is the point that's important with checksums and so on. Merkle
>> trees are great when you want to mirror structured data but CouchDB
>> replication is a mirror operation. Think, N db's replicating to a
>> central DB. you have a mixture of things which breaks checksums (or at
>> least any obvious application I can think of given our internal
>> structures)
>
> You're missing a rather important s/is/isn't/ there ;-)  But yeah, I agree.

Ah, thanks. That's why hash trees are a dead-end.
I think this is why I started to go down the replicating checkpoints
road in the first place.

Make documents like _checkpoint/<id>.
Instrument reading by protecting everything but _id. These become opaque.
Replicate them. Hoo-ray!
Diff/bisect the history of them using _revs_diff.

Something like this?

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