The impetus for these changes comes from the discussion in ACCUMULO-118. This API change and the issues surrounding the per-table Volume Chooser is a follow-on feature to Multi-Volume support that was added in 1.5. I want/need these changes.
In ACCUMULO-2844 you wanted, if not demanded, to make a breaking API change (changing the name of the Master) in the development and all bug fix branches without discussion. Here we have a non-breaking API change in a major release and all of a sudden it's an issue. By that logic, we should scrub 1.7 for all API changes and revert them. At this point I would much rather have these changes committed in 2.0 just so we can stop having this ridiculous discussion. I'm happy to fork Accumulo and backport these fixes to the version I need. ----- Original Message ----- From: "Sean Busbey" <bus...@cloudera.com> To: "dev@accumulo apache. org" <dev@accumulo.apache.org> Sent: Tuesday, December 2, 2014 1:14:50 PM Subject: Re: [VOTE] ACCUMULO-3176 Responses below. I feel like most of these questions (with the noted exception of details on my issue with one of the late compromise positions) were previously answered, but I've tried to add additional detail below where I may have been unclear in prior exchanges. While I agree that objections are the start of a conversation, votes are meant to be provide closure so the community can move on to other work. I'd ask that we try to bring this thread to a close. On Mon, Dec 1, 2014 at 2:40 PM, Keith Turner <ke...@deenlo.com> wrote: > > > The question I was most curious about was why you are ok w/ making this API > change in 2.0 but not 1.7.0. I do not understand the reasoning behind > this. > As a matter of background, over time I have become more convinced of the need for a stable, coherent API. Too many of the end users I have seen endure substantial work because of our altering of the API. This applies equally for forwards and backwards compatibility. When someone has a requirement to use our software and they find that the particular version they need to integrate with is different than they initially expected, I would like them to not have to endure project delays merely for updating use of our API. For 2.0, we already have broad consensus around improving our API in ACCUMULO-2589 despite the cost it puts on our user base; both because of a better delineation of what is and is not expected to stay constant and because we'll have a better formulation of a lifecycle for Accumulo related resources. In that particular matter, it's the proper lifecycle that I personally find compelling enough to broadly cause a burden. This is probably colored by my having dealt with ACCUMULO-2128 and its ilk. So, given that we're going to be asking our users to deal with a headache come 2.0 (which will hopefully be in the next 6-9 months) I would prefer to minimize asking them to take on dealing with changes in versions prior to that. There may be some future issue that fixes something severe enough to warrant changing my position on the matter. This issue did not. I talked previously about my position on API changes in general in the background info for Josh’s message: http://s.apache.org/HJg and I had meant to cover the "we already agreed to break things in 2.0" side in this admittedly short offer of compromise: http://s.apache.org/imf On Mon, Dec 1, 2014 at 4:25 PM, Christopher <ctubb...@apache.org> wrote: > Explicit questions and outstanding requests for clarification since your > last response (see previous emails for details and context): > -> So, are you arguing for no more API additions until 2.0? > My general preference, as mentioned above and previously in the background info Josh asked for, is to avoid API changes prior to 2.0. I am not arguing that this stance be taken on as a matter of course through this particular vote. I think any change to our API, prior to 2.0 or after, should be carefully considered. How we plan for users to interact with our software over time matters. Through removals we will be directly impacting the ability of operational users to adopt our newer versions. Through additions we will be impacting how system integrators go about building applications above us. It does neither us nor them any good for our API to change merely because it improves our abstractions or condenses our support footprint. In the consideration of the above and the nice-to-have fixes this particular patch brings, I think it can wait for the API overhaul in 2.0. The same two previous mailings I mentioned above to Keith are where I went through this previously. > -> Please address the fact that there is no breakage here... -> Another reasonable compromise has also been proposed that seems to address all of your concerns. Please explain why it does not. I think these are the same question, presuming your "other compromise" is the one of adding the new API and leaving the extant create methods undeprecated. If not, please let me know what other compromise I missed so that I can respond accordingly. I covered the breakage part of this explicitly in my response to Keith's question about which part of the API move I was concerned with: http://s.apache.org/nn5 Essentially, moving our table creation API to use a configuration object instead of the myriad of different arguments is a shift in how we expect users to interact with Accumulo. Even if the breakage doesn't happen right now, this change is setting downstream users up for pain when the break happens. To that same end, users attempting to proactively stay up to date on our API will break if they have to move backwards. Yes, this a normal part of API evolution. Yes, users will have to do this at some point. I'm merely stating that we have already reached consensus on that point being 2.0 and we should reserve using up the good will of our end users. Similarly, simply expanding our API to have multiple long term ways of doing table creation isn't tenable. For one, downstream users will ask which method to use. Deprecation is how we normally offer them clear guidance on where the API is going in the future. Without that, we'll just be using some proxy for deprecation (either a javadoc or emails on user@). Additionally, since the version that takes a single configuration object is clearly the most sustainable approach, the other methods are likely to be deprecated and then removed should we end up with additional major versions prior to 2.0. I covered some of this concern in my response to Brian in the first part of my last response: http://s.apache.org/0um > -> Please explain how you see omitting this API addition is compatible with > [the goal of supporting non-major intermediate releases]. Please also > explain why, if you consider 1.7 to be a major (expected) release, why such > an addition would not be appropriate, but would be appropriate for a future > major release (2.0). I believe I covered this through a combination of the above explanations to Keith and my response to Brian in the first part of my last response: http://s.apache.org/0um That we are having a 1.7 release at all is a matter of scheduling. There are already too many things different in that development line for us to release it as a follow on to 1.6 but not enough of our goals for 2.0 are done to get that release out. That doesn't mean we should feel free to pack as many breaking changes as we want into the release. > > Brian also asked: > -> I don’t see what breakage users would be required to deal with if the > proposed changes were made. A new method would be added to the API and some > existing methods deprecated (presumably to be removed in 2.0). So how would > this hurt our users? > I think this is covered above. In summary, when we alter our API we need to consider long term impact rather than just the immediate release. We are already going to ask our users to handle major changes in a relatively short time period. > -> Given that you are ok with with the change in 2.0, it seems that your > objection is not to the content of the change but rather the timing of it. > Given that users aren’t required to use the new API method added by the > change, this objection and the veto seem invalid to me. Am I missing > something? > I believe the rest of this message restates in detail my concerns about our API evolution and specifically why I am on board with the planned breakage in the 2.0 release. Let me know where there are particular gaps so I can help clarify. Please everyone stop this divisive tactic of continuing to claim my veto is invalid. The surface of our API and our impact on downstream users are valid technical considerations. Our bylaws clearly state what is needed for a veto to be sustained and I have already passed that bar. Let’s focus our discussion on the underlying problem rather than technicalities of our governance. -- Sean
