For what it's worth, Yarn Timeline Service v2 makes use of Tags only in the coprocessor code in the custom Scanner that is invoked during get/scan/compact and at the PrePut step.
thanks Vrushali On Fri, Sep 22, 2017 at 9:20 AM, Andrew Purtell <andrew.purt...@gmail.com> wrote: > I think not making the relevant APIs LP(Coprocessor) was an oversight. In > my opinion we should do that. I'm not sure about Public. We could do that > too but somewhere we need to call out that coprocessors have access to > tags, but not clients. (Tags are removed at RPC except for replication.) LP > doesn't imply what Public might. > > > On Sep 22, 2017, at 9:11 AM, Andrew Purtell <andrew.purt...@gmail.com> > wrote: > > > > Tags are server side internal metadata. Some carry sensitive information > like labels. I guess this could appear odd if not around for discussion > when they were introduced. So what documentation can be improved to lessen > the surprise? Javadoc? Online book? A JIRA with suggestions welcome. > > > > > >> On Sep 22, 2017, at 9:07 AM, Josh Elser <els...@apache.org> wrote: > >> > >> I can appreciate how we've gotten to this point, it just struck me > extremely odd that the contents of a Tag weren't expected to be accessed by > users. "Arbitrary metadata that rides along with a cell, you just can't see > that metadata" ;) > >> > >> I totally understand not wanting to let another thing come into 2.0. > Like MikeD said, let's hope for a faster 3.0 and we can slate this for that > time. > >> > >> Thanks for entertaining the discussion. We'll just deal with the > "downstream pain" for 2.0. > >> > >>> On 9/22/17 1:32 AM, ramkrishna vasudevan wrote: > >>> CellUtil similar type of methods. Coming to Tags yes there are not > much > >>> cases where clients can directly set Tags. And I think we don't expose > any > >>> APIs which allow you to use mutations with Tags. So probably moving to > >>> LimitedPrivate is better and mark with Evolving if there are some users > >>> depending on the internals of Tags and its impl. But this will be a > One of > >>> case. > >>> And also since Tags are internal ideally the CellUtil#getTAgs() should > have > >>> been in another Util method that is exposed with LimitedPrivate and > also > >>> Tags if tags should be made LimitedPRivate. So this may help in not > having > >>> a PRivate interface like Tag in a public CellUtil class. > >>> 3.0 is fine but need some clean up in 2.0? Indicating what could happen > >>> going forward from 2.0? > >>> Regards > >>> Ram > >>>> On Fri, Sep 22, 2017 at 2:59 AM, Sean Busbey <bus...@apache.org> > wrote: > >>>> Yeah. I mean, I think we should improve the situation. Just think > >>>> it's too much to bite off at this stage of 2.0, we can aim for 3.0 and > >>>> start working in some tooling to help us. > >>>> > >>>>> On Thu, Sep 21, 2017 at 3:35 PM, Josh Elser <els...@apache.org> > wrote: > >>>>> That really makes me groan (we have downstream users depending on > code > >>>> we've > >>>>> explicitly said "don't use"), but if that's what it is given the > current > >>>>> state, so be it. My complaining won't fix it. > >>>>> > >>>>> Thanks. > >>>>> > >>>>> > >>>>>> On 9/21/17 4:25 PM, Sean Busbey wrote: > >>>>>> > >>>>>> We have lots of examples of including non-Public stuff in Public > APIs. > >>>>>> we have docs that advise folks to be wary on relying on them beyond > >>>>>> opaque symbols. > >>>>>> > >>>>>> ref: http://hbase.apache.org/book.html#hbase.client.api.surface > >>>>>> > >>>>>>> On Thu, Sep 21, 2017 at 3:21 PM, Josh Elser <els...@apache.org> > wrote: > >>>>>>> > >>>>>>> I was going to suggest LimitedPrivate in my original, but this > doesn't > >>>>>>> make > >>>>>>> sense as we're exposing Public API via CellUtil. > >>>>>>> > >>>>>>> It seems odd to me that we wouldn't treat the cell tags as a > supported > >>>>>>> API > >>>>>>> call. However, I'm happy to remain "confused" if the rest of folks > >>>> don't > >>>>>>> consider tags to be intended for users :) > >>>>>>> > >>>>>>> > >>>>>>>> On 9/21/17 3:15 PM, Ted Yu wrote: > >>>>>>>> > >>>>>>>> > >>>>>>>> Can we mark Tag LimitedPrivate ? > >>>>>>>> > >>>>>>>> We know how ATS uses Tags so it should be straight forward to keep > >>>> their > >>>>>>>> usage intact. > >>>>>>>> > >>>>>>>> On Thu, Sep 21, 2017 at 12:03 PM, Josh Elser <els...@apache.org> > >>>> wrote: > >>>>>>>> > >>>>>>>>> Hiya, > >>>>>>>>> > >>>>>>>>> (Background, I'm starting what is likely to be an onerous task of > >>>>>>>>> looking > >>>>>>>>> through downstream components and seeing what is broken with the > >>>> latest > >>>>>>>>> hbase-2.0.0*) > >>>>>>>>> > >>>>>>>>> Looking at YARN's use of HBase for the Application > TimelineServer, I > >>>>>>>>> see > >>>>>>>>> that they're relying on the Tag interface. > >>>>>>>>> > >>>>>>>>> Presently, Tag is marked as Private, yet we expose it via the > Public > >>>>>>>>> CellUtil. > >>>>>>>>> > >>>>>>>>> My gut reaction is that we should bump Tag up Public since the > intent > >>>>>>>>> is > >>>>>>>>> for downstream users to, ya know, use those Tags. Any objections? > >>>>>>>>> > >>>>>>>>> If we don't want to expose Tag, we should make a pass over the > Public > >>>>>>>>> methods and mark them as Private (so not as to provide a Public > >>>> method > >>>>>>>>> with > >>>>>>>>> Private objects). CellUtil#getTag(Cell, byte) would be one such > >>>>>>>>> example. > >>>>>>>>> > >>>>>>>>> - Josh > >>>>>>>>> > >>>>>>>> > >>>>>>> > >>>>> > >>>> >
