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https://issues.apache.org/jira/browse/COUCHDB-1259?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13089982#comment-13089982
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Jason Smith commented on COUCHDB-1259:
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@Paul, I overlooked or misunderstood Randal's point about duplicating the UUID.
Makes sense.
@Paul and Jens, totally: URLs are unstable. And, in general, on the web, if a
URL changes, that is a huge piece of information. That is a huge hint that you
need to re-evaluate your assumptions. Exhibit A: the replicator starts from
scratch if you give it a new URL. That is the correct general solution.
Your requirement to change the couch URL and everything is just fine and the
application doesn't have to worry--I think that requirement is asking CouchDB
to be a bad web citizen. In other words, IMO you have an application-level
problem, not a couch problem, *except* that even if you could determine
everything is alright, you can't specify the replication ID.
I think Damien just time-traveled again.
BTW, @Jens, you can already give Apache CouchDB a UUID for your own needs. If
you have admin access, just put it anywhere, /_config/jens/uuid. If an
unprivileged client must know this UUID, then change the "Welcome" mesage in
_config/httpd_global_handlers/%2f. Any unprivileged client can find it there.
(You could also place the UUID in the authentication realm in
_config/httpd/WWW-Authenticate which actually sounds sort of appropriate.)
Finally, if you are willing to run a fork (which mobile Couchbase is) then you
could add any feature you need which doesn't make sense for Apache CouchDB.
> 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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