Many thanks ShaoFeng Shi,
I understand this could be necesary to support snowflake schema.
However, some BI tools could generate queries putting first a dimension
table and after the fact table, with correct ANSI-92 SQL sintax but
incorrect for Kylin 2.1. Maybe could be useful and option to select
between Star Schema and Snowflake schema when you define data model on
Kylin. What do you think about?
Best Regards,
El 23/10/2017 a las 10:10, ShaoFeng Shi escribió:
Should be related to the snowflake support; Now all joined query
should start from the fact table. Add the second join doesn't work I
believe.
2017-10-22 0:36 GMT+08:00 Roberto Tardío <[email protected]
<mailto:[email protected]>>:
Hi,
I have replaced (not updated) Kylin 1.6 for Kylin 2.1. I created a
cube (and also underlying model) with the same sources and
metadata that I have used for the same I previously implementend
on Kylin 1.6. The cube construcction was Ok. However, some strange
occurs with join queries. The following query goes
/F_RENDIMIENTO is the fact table and //D_CURSO_ACADEMICO_VK is a
dimension table:
/
/select D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO, sum(CREDITOS)/
/from F_RENDIMIENTO JOIN D_CURSO_ACADEMICO_VK ON
F_RENDIMIENTO.ID_CURSO_ACADEMICO =
D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO/
/group by D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO/
But susprisingly if I change the INNER JOIN order the following
query does not go
/select D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO, sum(CREDITOS)//
//from D_CURSO_ACADEMICO_VK JOIN F_RENDIMIENTO ON
F_RENDIMIENTO.ID_CURSO_ACADEMICO =
D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO//
//group by D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO/
/Error while executing SQL "select
D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO, sum(CREDITOS) from
D_CURSO_ACADEMICO_VK JOIN F_RENDIMIENTO ON
F_RENDIMIENTO.ID_CURSO_ACADEMICO =
D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO group by
D_CURSO_ACADEMICO_VK.ID_CURSO_ACADEMICO LIMIT 50000": No
realization found for
rel#7393:OLAPTableScan.OLAP.[](table=[DM_ACAD_KYLIN_ORC,
D_CURSO_ACADEMICO_VK],fields=[0, 1]), JoinDesc [type=INNER,
primary_key=[ID_CURSO_ACADEMICO], foreign_key=[ID_CURSO_ACADEMICO]]/
This does not happend with the same cube implemented using Kylin 1.6.
Why does this happen?
Maybe is related to the new snowflake schema support. I used I a
star schema and I defined the INNER JOIN as I show in the next picture
Maybe I have to add a second explicit JOIN between
D_CURSO_ACADEMICO --> F_RENDIMIENTO, i.e, the inverted join.
Regards,
Roberto
--
*Roberto Tardío Olmos*
/Senior Big Data & Business Intelligence Consultant/
Avenida de Brasil, 17
<https://maps.google.com/?q=Avenida+de+Brasil,+17&entry=gmail&source=g>,
Planta 16.28020 Madrid
Fijo: 91.788.34.10
--
Best regards,
Shaofeng Shi 史少锋
--
*Roberto Tardío Olmos*
/Senior Big Data & Business Intelligence Consultant/
Avenida de Brasil, 17, Planta 16.28020 Madrid
Fijo: 91.788.34.10
