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From Paul Davis <>
Subject Re: [DISCUSSION] Emit an instance ID value in DB info API response in CouchDB 4.0
Date Tue, 26 May 2020 18:37:27 GMT
We already have the uuid generated. I'd suggest just adding a `uuid`
field that exposes it.

On Tue, May 26, 2020 at 1:27 PM Nick Vatamaniuc <> wrote:
> Hi everyone,
> I was wondering if we could expose an "instance_id" field in the top
> level `/<db>` (db_info) result. The value would be a uuid which is
> unique for every database instance. That is, if a database is deleted
> and re-created with the same name, it would have a different
> "instance_id". [*]
> We'd get at least 2 benefits from it:
> 1) Replicator could eventually could be updated to checkpoint on the
> target only, and thus have a read-only access to the source. Currently
> we need to checkpoint on the source to account for the case when the
> source db has been recreated, so we maintain the checkpoint history on
> the source and the target.
> 2) User's code might want to know if it the database has been
> recreated, mostly to avoid mishaps when they continue performing
> requests against the db with the same, which now may have completely
> different data in it.
> What do we think, do we like this idea?
> Cheers,
> -Nick
> [*] Back in 1.x we had the "instance_start_time" field which does
> mostly same thing, but is based on time. In 2.x and 3.x we still emit
> that field and for compatibility and hard code it to "0". We could
> re-use that field, but I think since the idea is to make it a uuid and
> not a timestamp so it's name doesn't quite match and it would have a
> different format (64bits vs 128bits).

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