HI! I have spent a few weeks getting Phoenix working with HBase 3, and while I'm not done, I am at the point where everything compiles and most unit tests run.
My VERY WIP patch is at https://github.com/apache/phoenix/pull/1815, in case you want to check. I want to get the discussion started, as keeping the code in one branch requires some rather ugly hacks. PROTOBUF CHANGES The biggest difference is that HBase 3 removes protobuf 2.5, and the unshaded hbase-protocol classes, and moves everything to protobuf 3. While in the grand scheme of things this is great, it is a serious challenge to us. The solution suggested in the HBase docs is basically just performing text replacement using the maven-replacer-plugin, and I could not find a way to avoid this. This means that when building for HBase 3, we copy everything to a tmp directory, do a string replacement on the protobuf and hbase-protocol packages in the source, then add these to the build with the build-helper plugin. Surprisingly, my Eclipse picks up these changes, and it IS possible to debug the generated code with some minor inconveniences. I have also considered simply switching the shaded libraries for HBase 2 as well, but some of the classes we use (f.e. RPCController) are simply not there in Hbase 2.x (in the shaded packages), so I did not pursue this direction. If you think we should explore this direction, then I can make more effort here. While the HBase docs does not talk about this, I will also check if it is possible to use protoc 3.x in the HBase 3 build. OTHER API CHANGES There are some minor API changes that can be handled just fine with the usual compatibility modules, but there are also quite a few removed APIs. We have already made a pass to replace HBase 1.x APIs, but there is still work to do here. The good news is that the replacements for the removed APIs also work with HBase 2.x, so they can be replaced anytime. I plan to put up a PR to replace these APIs as soon as 5.2 is released. This way the actual HBase 3 patch will be much smaller and easier to rebase as needed. CI As soon as HBase 3 support lands, we should make sure to at least compile Phoenix with HBase 3 for every PR, lest old API calls creep back. Looking forward to your suggestions, questions or comments Istvan
