Hi ShaoFeng, Thank you. I'll check that.
Best Regards, Hari On Mon, 24 Sep 2018, 11:59 ShaoFeng Shi, <[email protected]> wrote: > Hi Hari, > > You're right that Cube has joined data (from fact and lookup tables), and > then aggregate them by the dimensions. But Kylin doesn't keep the raw data > after the cube be built, only keep the cuboid (group by certain > dimensions), so couldn't answer the "select * " without "group by" query. > > The logic to pushdown is quite simple today. Please look at > QueryService#executeRequest(); > When Cube throws an exception, it redirects to the pushdown engine. > > hosur narahari <[email protected]> 于2018年9月21日周五 上午11:11写道： > >> Hi ShaoFeng, >> >> Thanks for your response. I've few follow up questions. >> >> 1. In FAQ, it's mentioned that "The cube only has aggregated data, so >> all your queries should be aggregated queries". But since cube is created >> by joining based on various dimensions, shouldn't joins without aggregation >> be valid cube querying scenarios(I hope it's already being done). >> >> 2. "select price from " statement should also be pushed down, the rule >> can be optimized for it. Can you point me to documentation for specifying >> pushdown rules. It would be of big help. >> >> Thanks & Regards, >> Hari >> >> On Thu, Sep 20, 2018 at 5:27 PM ShaoFeng Shi <[email protected]> >> wrote: >> >>> Hi Hosur, >>> >>> Firstly, please check Kylin's FAQ, search "Why I got an error when >>> running a “select * “ query?": >>> https://kylin.apache.org/docs/gettingstarted/faq.html >>> >>> Maybe the "select price from " statement should also be pushed down, the >>> rule of pushdown can be optimized for it. >>> >>> hosur narahari <[email protected]> 于2018年9月20日周四 上午11:15写道： >>> >>>> Hi, >>>> >>>> I was trying out kylin with sample-cube example. And when I run >>>> "select * from kylin_sales" query, it returns all the values correctly. But >>>> when >>>> I run "select price from kylin_sales", it returns null in all rows. >>>> Price also was coming correctly in first scenario. >>>> >>>> One more thing is, first query is pushed down to hive and second one is >>>> fetched from cube. And yes, I've enabled pushdown. >>>> >>>> Please let me know if I'm missing something. >>>> >>>> Best Regards, >>>> Hari >>>> >>> >>> >>> -- >>> Best regards, >>> >>> Shaofeng Shi 史少锋 >>> >>> > > -- > Best regards, > > Shaofeng Shi 史少锋 > >
