On Tue, Jul 30, 2013 at 3:29 PM, Andrew Purtell <apurt...@apache.org> wrote: > Perhaps you can elaborate on the difference you see between HFileV3 and > namespaces?
Sure. From my perspective, Namespaces: * arrived earlier in the merge window. * Has been run publicly on a large cluster * Has had more public reviews. * Was re-worked to get closer to a greenfield best implementation * Is closer to being merged * Is less prone to have unforeseen perf impacts. * Is almost impossible to create without needing downtime ** (hence it should go in the singularity if possible). HFileV3: * Showed up very late in the merge window * Still needs revisions * Hasn't been put on large clusters publicly. * Is not the green field HFileV3, and doesn't have time for a complete re-do * Can easily be done without out downtime ** (changing the encoders could be done without needing downtime. meaning no singularity is required). * Will 100% have perf impacts. None of that actually has anything to do with what I think is a more exciting feature. It's all about stability of the project and trying to find a way move us towards the stable and externally explainable release cycles that other real databases have. I'm actually really excited about tagging. It could allow a lot of new and cool features without adding too much core code.
