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https://issues.apache.org/jira/browse/COUCHDB-1259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13089841#comment-13089841
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Randall Leeds commented on COUCHDB-1259:
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I'd rather see the replicator respect a naming field. CouchDB core places no 
specific significance on the replication documents, treating them as any other 
document in the _local/ namespace. And we've heard a number of times, 
especially in the last few weeks, about how config files (and specifically ones 
that change) are ugly.

I proposed UUIDs at the DB level a long time ago for this reason, and relatedly 
so that you could trigger push/pull without using HTTP at both sides and have 
it be the same replication (discover that you are a host via UUID). 
Configuration files would work to make it server level, but it's hacky. 
DB-level is a bad idea because sysadmins might copy couch files. Ultimately, 
the client should identify the replication if it can. I think that's the best 
solution.

> Replication ID is not stable if local server has a dynamic port number
> ----------------------------------------------------------------------
>
>                 Key: COUCHDB-1259
>                 URL: https://issues.apache.org/jira/browse/COUCHDB-1259
>             Project: CouchDB
>          Issue Type: Bug
>          Components: Replication
>    Affects Versions: 1.1
>            Reporter: Jens Alfke
>
> I noticed that when Couchbase Mobile running on iOS replicates to/from a 
> remote server (on iriscouch in this case), the replication has to fetch the 
> full _changes feed every time it starts. Filipe helped me track down the 
> problem -- the replication ID is coming out different every time. The reason 
> for this is that the local port number, which is one of the inputs to the 
> hash that generates the replication ID, is randomly assigned by the OS. (I.e. 
> it uses a port number of 0 when opening its listener socket.) This is because 
> there could be multiple apps using Couchbase Mobile running on the same 
> device and we can't have their ports colliding.
> The underlying problem is that CouchDB is attempting to generate a unique ID 
> for a particular pair of {source, destination} databases, but it's basing it 
> on attributes that aren't fundamental to the database and can change, like 
> the hostname or port number.
> One solution, proposed by Filipe and me, is to assign each database (or each 
> server?) a random UUID when it's created, and use that to generate 
> replication IDs.
> Another solution, proposed by Damien, is to have CouchDB let the client work 
> out the replication ID on its own, and set it as a property in the 
> replication document (or the JSON body of a _replicate request.) This is even 
> more flexible and will handle tricky scenarios like full P2P replication 
> where there may be no low-level way to uniquely identify the remote database 
> being synced with.

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