I found it confusing initially until I read about how it is mostly a method of optimising the cube (rather than a separate type of dimension that would be queried differently). It makes a lot of sense now that I understand, but perhaps a little bit more documentation would help others starting out. (it is not covered in the cube construction slides)
Not a huge deal though On Mon, Sep 21, 2015 at 3:21 PM, Julian Hyde <[email protected]> wrote: > Yes, hierarchies may be a useful organizing concept. I claim that > hierarchies are separate things: (1) navigation paths for a UI, (2) > statistical patterns in data access. Conversations like this one are > evidence that — at least for some people — hierarchies are confusing. So, > keep them as a user concept only if they make life simpler for the majority > of users. > > Julian > > > > On Sep 21, 2015, at 2:34 AM, Li Yang <[email protected]> wrote: > > > > @Julian, plan to refactor the underlying aggregation group in Q4. Will > drop > > hierarchy concept in the backend, however in the frontend for ease of > > understanding, may still call it hierarchy. :-) > > > > On Sat, Sep 19, 2015 at 2:40 AM, Patrick McAnneny < > > [email protected]> wrote: > > > >> Great thread and great read. I see now that hierarchies are just a way > to > >> specify correlated dimensions for added efficiencies in cube > architecture. > >> I understand now. Thanks a lot! > >> > >> On Fri, Sep 18, 2015 at 1:08 PM, Julian Hyde <[email protected]> wrote: > >> > >>> As I've said before[1] I don't think hierarchies add much to Kylin. > >>> > >>> Julian > >>> > >>> [1] > >>> > >> > http://mail-archives.apache.org/mod_mbox/kylin-dev/201506.mbox/%[email protected]%3E > >>> > >>> On Fri, Sep 18, 2015 at 9:18 AM, Patrick McAnneny > >>> <[email protected]> wrote: > >>>> So does a regular dimension though right? What's the difference > >> between a > >>>> singular hierarchy dimension and a regular dimension? The end > resulting > >>>> kylin sql would be the same (group by) right? Thanks for helping me > >>>> understand! > >>>> > >>>> On Fri, Sep 18, 2015 at 12:01 PM, Sarnath <[email protected]> wrote: > >>>> > >>>>> Hierarchy indicates that drill down is possible. > >>>>> > >>> > >> > >
