In Kylin 1.x as it only allow one Fact table, you have to join multiple big tables as one before using in Cube. Of course you can do that with a Hive view, so all joins are over fly when Kylin fetches data from Hive. The impact is, when query Kylin you need to use the name of the joined table, instead of original fact table name.
>From Kylin 2.x, it supports multiple Fact tables in one Cube; You don't need create additional view or flat table, just use the original names. 2017-03-09 9:45 GMT+08:00 Sonny Heer <sonnyh...@gmail.com>: > to clarify in my use case the data can be organized to either have a > couple fact tables or a large single one. Queries are open ended at this > point. queries may cross facts or may not. > > On Wed, Mar 8, 2017 at 5:13 PM, Sonny Heer <sonnyh...@gmail.com> wrote: > >> Let me put it anther way. assume a SALES table and a PRODUCT table. >> This is not highly normalized in the grand scheme of things, but somewhat. >> The question is what benefit is there to denormalize this further into a >> single table for kylin. i read something about hierarchical dimensions. >> So from Kylin perspective which is better. have one-to-many in a single >> table or some normalized form? >> >> On Wed, Mar 8, 2017 at 4:24 PM, Billy Liu <billy...@apache.org> wrote: >> >>> please check star schema first： https://en.wikipedia.or >>> g/wiki/Star_schema >>> >>> 2017-03-08 12:48 GMT-08:00 Sonny Heer <sonnyh...@gmail.com>: >>> >>>> Hi I'm somewhat new to Kylin. we have a relational db schema imported >>>> into hive as is at the moment. The schema is highly normalized with lots >>>> of tables. I can see this database having multiple fact tables or a >>>> handful of fact tables. >>>> >>>> In Kylin I see when creating a model (star) you have the option to pick >>>> a single fact table...meaning there is a single cube per fact table. >>>> Please provide pros/cons on running transformations to denormalize the >>>> tables into a single table vs keeping lots of tables with many fact/lookup >>>> tables. >>>> >>>> In short: >>>> should we do any transformations in Hive before presenting the tables >>>> to kylin for cubing?... >>>> >>>> Thanks >>>> >>> >>> >> >> >> -- >> >> >> Pushpinder S. Heer >> Senior Software Engineer >> m: 360-434-4354 <(360)%20434-4354> h: 509-884-2574 <(509)%20884-2574> >> > > > > -- > > > Pushpinder S. Heer > Senior Software Engineer > m: 360-434-4354 h: 509-884-2574 > -- Best regards, Shaofeng Shi 史少锋
