Thanks Arpit!
On Tue, Jul 29, 2014 at 2:24 PM, Arpit Agarwal <aagar...@hortonworks.com> wrote: > I cleared out the wiki page and left a forwarding link to the site docs. > From a quick scan all the content is included in the site docs. > > > On Tue, Jul 29, 2014 at 2:14 PM, Sandy Ryza <sandy.r...@cloudera.com> > wrote: > > > Eli pointed out to me that this is the up-to-date compatibility guide: > > > > > http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/Compatibility.html > > > > Thanks, > > Sandy > > > > > > On Tue, Jul 29, 2014 at 9:39 AM, Sandy Ryza <sandy.r...@cloudera.com> > > wrote: > > > > > Hi Zhijie, > > > > > > The Hadoop compatibility guide mentions this as "semantic > compatibility": > > > http://wiki.apache.org/hadoop/Compatibility > > > > > > My interpretation of the section is that we can't change the behavior > of > > > public APIs unless we're fixing buggy behavior. If the change could > > break > > > an existing application that's behaving reasonably with respect to the > > old > > > API, it's an incompatible change. > > > > > > -Sandy > > > > > > > > > > > > On Tue, Jul 29, 2014 at 9:26 AM, Zhijie Shen <zs...@hortonworks.com> > > > wrote: > > > > > >> Hi folks, > > >> > > >> Recently we have a conversation on YARN-2209 about the incompatible > > >> changes > > >> over releases. For those API changes that will break binary > > compatibility, > > >> source compatibility towards the existing API users, we've already > had a > > >> rather clear picture about what we should do. However, YARN-2209 has > > >> introduced another case which I'm not quite sure about, which is kind > of > > >> *logic > > >> incompatibility*. > > >> > > >> In detail, an ApplicationMasterProtocol API is going to throw an > > exception > > >> which is not expected before. The exception is a sub-class of > > >> YarnException, such that it doesn't need any method signature change, > > and > > >> won't break any binary/source compatibility. However, the exception is > > not > > >> expected before, but needs to be treated specially at the AM side. Not > > >> being aware of the newly introduced exception, the existing YARN > > >> applications' AM may not handle it exception properly, and is at the > > risk > > >> of being broken on a new YARN cluster after this change. > > >> > > >> An additional thought around this problem is that the change of what > > >> exception is to throw under what situation may be considered as a > *soft > > >> *method > > >> signature change, because we're supposed to write this javadoc to tell > > the > > >> users (though we didn't it well in Hadoop), and users refer to it to > > guide > > >> how to handle the exception. > > >> > > >> In a more generalized form, let's assume we have a method, which > behaves > > >> as > > >> A, in release 1.0. However, in release 2.0, the method signature has > > kept > > >> the same, while its behavior is altered from A to B. A and B are > > different > > >> behaviors. In this case, do we consider it as an incompatible change? > > >> > > >> I think it's somewhat a common issue, such that I raise it on the > > mailing > > >> list. Please share your ideas. > > >> > > >> Thanks, > > >> Zhijie > > >> > > >> -- > > >> Zhijie Shen > > >> Hortonworks Inc. > > >> http://hortonworks.com/ > > >> > > >> -- > > >> CONFIDENTIALITY NOTICE > > >> NOTICE: This message is intended for the use of the individual or > entity > > >> to > > >> which it is addressed and may contain information that is > confidential, > > >> privileged and exempt from disclosure under applicable law. If the > > reader > > >> of this message is not the intended recipient, you are hereby notified > > >> that > > >> any printing, copying, dissemination, distribution, disclosure or > > >> forwarding of this communication is strictly prohibited. If you have > > >> received this communication in error, please contact the sender > > >> immediately > > >> and delete it from your system. Thank You. > > >> > > > > > > > > > > -- > CONFIDENTIALITY NOTICE > NOTICE: This message is intended for the use of the individual or entity to > which it is addressed and may contain information that is confidential, > privileged and exempt from disclosure under applicable law. If the reader > of this message is not the intended recipient, you are hereby notified that > any printing, copying, dissemination, distribution, disclosure or > forwarding of this communication is strictly prohibited. If you have > received this communication in error, please contact the sender immediately > and delete it from your system. Thank You. >
