Hi all, I committed a good bit of replication-related code today and  
wanted to check with the list regarding the 0.10 branch.  Here's what  
I changed ..

one flat-out bugfix,
r807308, r807354: more precise and accurate calculation of replication  
progress

one new feature that could be classified as a bugfix depending on your  
point-of-view,
r807342, r807345: follow 302 redirects during replication

and two significant performance improvements (thanks rnewson for all  
the stress testing):
r807320, r807360: checkpoint at most once per 5 seconds
r807208, r807459, r807461: minimize the number of full commit operations

There's another new feature hiding in that last set of commits, namely  
the ability to do a restricted full commit

POST /db/_ensure_full_commit?seq=N

which guarantees that everything up to and including update_seq N will  
be synced to disk.  This is a weaker guarantee than a vanilla  
_ensure_full_commit, and as a result it can be much faster in certain  
situations (e.g. replication from a server experiencing a heavy  
batch=ok write load).

I'd like to merge all of these into the 0.10 branch if that abides by  
our release policies. Best,

Adam