Aggregation groups is to reduce the cube calculation and storage; Lets see a simple case:
Say we have a cube has 6 dimensions: [A B C D E F] It will has 2^6 cuboids: 64; If your query pattern is: [group by A, B, C] or [group by D, E, F], then you can split the 6 dimensions to two groups: [A B C], [D E F]; Then Kylin will skip some cuboid like AD, AE, Š; The total cuboid count will be 2^3 + 2^3 = 16, which is much less than the original 64; On 3/31/15, 1:49 PM, "Abhishek Sinha" <[email protected]> wrote: >Went through the slide. Doesn't give much information about Advanced >Settings. > >On Tue, Mar 31, 2015 at 9:01 AM, jason zhong <[email protected]> >wrote: > >> Hi Abhishek, >> >> Aggregation Group is for cube optimization, >> >> Kylin will pick up dimension column and *fk on lookup table* as default >> rowkey and aggregation group item. >> >> you can refer >> http://www.slideshare.net/YangLi43/design-cube-in-apache-kylin >> to know more about cube creation first. >> >> and for kylin architecture >> >> >> >>http://www.slideshare.net/YangLi43/apache-kylin-deep-dive-2014-dec?next_s >>lideshow=1 >> >> >> >> On Mon, Mar 30, 2015 at 2:16 PM, Abhishek Sinha <[email protected]> >> wrote: >> >> > Can someone explain the following while designing the cube in Kylin? >> > >> > 1. New Aggregation Groups >> > 2. New RowKey Column >> > >> > By default, Kylin automatically picks up the some values for RowKey >>and >> > Aggregation groups in Advanced Settings Page. >> > a) How is that done? >> > b) When do we need add our own Aggregation Groups and RowKey? >> > c) How is RowKey related to Aggregation Groups? >> > d) What does length, dictionary and mandatory indicate? >> > >> > -- >> > Abhishek Sinha >> > Mobile: +919035191078 >> > infoworks.io >> > >> > > > >-- >Abhishek Sinha >Mobile: +919035191078 >infoworks.io
