When we moved to Hadoop 2.4, the associated protobuf upgrade (2.4.1 -> 2.5.0) proved to be one of the bigger problems. In our case, most of our users were using protobuf 2.4.x or earlier.
We identified a couple of places where the backward compatibility was broken, and patched for those issues. We've been running with that patched version of protobuf 2.5.0 since. I can push out those changes to github or something if others are interested FWIW. Regards, Sangjin On Tue, May 19, 2015 at 9:59 AM, Colin P. McCabe <cmcc...@apache.org> wrote: > I agree that the protobuf 2.4.1 -> 2.5.0 transition could have been > handled a lot better by Google. Specifically, since it was an > API-breaking upgrade, it should have been a major version bump for the > Java library version. I also feel that removing the download links > for the old versions of the native libraries was careless, and > certainly burned some of our Hadoop users. > > However, I don't see any reason to believe that protobuf 2.6 will not > be wire-compatible with earlier versions. Google has actually been > pretty good about preserving wire-compatibility... just not about API > compatibility. If we want to get a formal statement from the project, > we can, but I would be pretty shocked if they decided to change the > protocol in a backwards-incompatible way in a minor version release. > > I do think there are some potential issues for our users of bumping > the library version in a minor Hadoop release. Until we implement > full dependency isolation for Hadoop, there may be some disruptions to > end-users from changing Java dependency versions. Similarly, users > will need to install a new native protobuf library version as well. > So I think we should bump the protobuf versions in Hadoop 3.0, but not > in 2.x. > > cheers, > Colin > > On Fri, May 15, 2015 at 4:55 AM, Alan Burlison <alan.burli...@oracle.com> > wrote: > > On 15/05/2015 09:44, Steve Loughran wrote: > > > >> Now: why do you want to use a later version of protobuf.jar? Is it > >> because "it is there"? Or is there a tangible need? > > > > > > No, it's because I'm looking at this from a platform perspective: We have > > other consumers of ProtoBuf beside Hadoop and we'd obviously like to > > minimise the versions of PB that we ship, and preferably just ship the > > latest version. The fact that PB seems to often be incompatible across > > releases is an issue as it makes upgrading and dropping older versions > > problematic. > > > > -- > > Alan Burlison > > -- >
