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From Adam Kocoloski <kocol...@apache.org>
Subject Re: Replicating between CouchDB and BigCouch
Date Tue, 07 Dec 2010 15:25:56 GMT
On Dec 7, 2010, at 12:43 AM, Matt Adams wrote:

> Hi folks,
> 
> I have a scenario where it would be really great to leverage BigCouch at the data center
level and regular CouchDB at the mobile client level.
> 
> Are there any hurdles to doing this?  The intent is that replication will either involve
many smaller databases (most mobile clients will only need to replicate a few of these) or
a few very large databases in which case a client will likely only replicate a very small
subset of one of these databases (using filters and so on).
> 
> I would appreciate if anyone with a better knowledge of both projects would be able to
chime in with some reasons "why this would not work" or draw my attention to caveats.
> 
> 
> Thanks in advance,
> 
> Matt

Hi Matt, you'll want to be using 1.0.1 for this on the CouchDB side, as it contains some fixes
for dealing with the weird sequences transmitted by BigCouch.

Other than that, there's one bug I'm aware of that can cause the replicator to stop saving
checkpoints when BigCouch is used as a source.  The bug stems from the fact that the replicator
sorts sequences, and the BigCouch sequences are strings, so when the replicator sees a sequence
like "9999-..." it thinks it has reached the end of time :P  The replication will continue,
but it won't save any checkpoints, so the next time it runs it will scan through a bunch of
revisions again (but it will save checkpoints then).  Best,

Adam
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