We're looking at branching 0.6 today and starting 0.7 work. 0.6 shaped up to be a really nice follow-up to 0.5, where we improved just about everything while keeping the upgrade path super easy. (We changed the network around again, but no disk changes, so it's just going to be shutdown-and-restart.) Client APIs are 100% compatible, with the exception of get_key_range, which we had tagged as deprecated in 0.5 for removal in the next release.
So to recap recent history, we went from 0.4 to 0.5 to 0.6 without major client level API changes. I think that is an excellent record for where we were when we were releasing 0.4. 0.7 is probably going to be a little more painful, after which we hope to have things stable for another few releases, at the least. Tickets currently tagged 0.7 are here: https://issues.apache.org/jira/secure/IssueNavigator.jspa?reset=true&mode=hide&sorter/order=DESC&sorter/field=priority&resolution=-1&pid=12310865&fixfor=12314533 They are a good mix of - fundamental internals changes that we have been putting off so far (#674, #16, and friends) - stuff that we really really want to make ops better (#44) - pie in the sky new features (#749) - incremental improvements to what we already have The primary pain source from the client perspective is going to be the internals changes, particularly moving row keys from String to byte[]. But it's a change we've know need need to make and I think it's time to bite the bullet. Also, if we were to execute on all the tickets there, 0.7 would be this huge monster release that will take like 6 months to get out. i think that's too long. Shipping is feature #1 at this stage, I'm really scared of biting off too much and losing weeks or months to that. So what I'd like to propose is making 0.7 primarily about the internals changes and push for high-level queries in 0.8, where both of those hit our usual ~3 month release cycle. I don't think it makes sense to do those the other way around; introducing new APIs that we already know we need to break just seems mean. :) -Jonathan
