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Date: Mon, 29 Jul 2013 19:47:10 +0100
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 <CABvT1DFJ1P_-qndRR4ewWnVYYSqutzeya42wJBE5fQ45X7Cf=Q@mail.gmail.com>
Subject: Re: Two way replication question
From: Robert Newson <rnewson@apache.org>
To: "user@couchdb.apache.org" <user@couchdb.apache.org>
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CouchDB will check that the current revision of every document is
present on the target and will skip copying it if it is. In your case,
the replication will not transfer any documents at all but will check
every id/rev pair which will take some time.

B.


On 29 July 2013 19:37, James Marca <jmarca@translab.its.uci.edu> wrote:
> Hi,
>
> I have two machines, A and B.  I am running an analysis on A, saving
> the output to couchdb, and then replicating by push from A to B.
>
> B's database started life from this push replication, and has never
> been otherwise modified.  So the two are more or less identical.
>
> What I want to do now is parallelize my work flow and run more
> analyses on B, save locally (to B's couchdb), and then replicate those
> changes to A.  (The database is used both to save output, and also to
> keep track of what has been done already, so it is useful to keep the
> output db syncronized between all machines.)
>
> My question is whether replicating from B to A will require pushing
> all of the docs to A.  This is an issue because my database is 21 GB
> and growing, and I'd rather not push all that data from B to A when I
> *know* the two are identical right now.
>
> Is there a way to set up replication to skip everything already there?
> Or to copy the replication state from A to B so that B knows that
> replication with A can start with new data only?
>
> If not, I can of course just save work done on B to the CouchDB on A
> directly, but I'd rather set it up so that the computation process
> always just hits couchdb on localhost, and let couchdb do the machine
> to machine copying.
>
> Thanks for any insights or pointers to the correct docs page,
>
> James Marca