hi Jacky & Ravindra, I have little more query about this design, thank you
very much can clarify my query.
1. if we support create aggreagation tables from two or more tabels join,
how to set the aggretate.parent?, whether can be like
'aggretate.parent'='fact1,dim1,dim1'
2. what's the agg table colum name ? for following create command it will be
as: user_id,name,c2, price ?
CREATE TABLE agg_sales
STORED BY 'carbondata'
TBLPROPERTIES ('aggregate.parent'='sales')
AS SELECT user_id,user_name as name, sum(quantity) as c2, avg(price) FROM
sales GROUP BY user_id.
3. if we create the dictioanry column in agg table, whether the dictionary
file will use the same one main table?
4. for rollup table main table creation: what's the mean for
timeseries.eventtime, granualarity? what's column can belong to this?
5. for rollup table main table creation: what's the mean for
‘timeseries.aggtype’ =’quantity:sum, max', it means the column quantity only
support sum, max ?
6. In both the above cases carbon generates the 4 pre-aggregation tables
automatically for
year, month, day and hour. (their table name will be prefixed with
agg_sales). -- in about cause only see the column hour, how to generate the
year, month and day ?
7.In internal implementation, carbon will create these table with
SORT_COLUMNS=’group by
column defined above’, so that filter group by query on main table will be
faster because it
can leverage the index in pre-aggregate tables. -- I suggstion user can
control the sort columns order
8. whether support merge index to agg table ? -- it is usefull.
Jacky Li wrote
> Hi community,
>
> In traditional data warehouse, pre-aggregate table or cube is a common
> technology to improve OLAP query performance. To take carbondata support
> for OLAP to next level, I’d like to propose pre-aggregate table support in
> carbondata.
>
> Please refer to CARBONDATA-1516
> <https://issues.apache.org/jira/browse/CARBONDATA-1516> and the
> design document attached in the JIRA ticket
> (https://issues.apache.org/jira/browse/CARBONDATA-1516
> <https://issues.apache.org/jira/browse/CARBONDATA-1516>)
>
> This design is still in initial phase, proposed usage and SQL syntax are
> subject to change. Please provide your comment to improve this feature.
> Any suggestion on the design from community is welcomed.
>
> Regards,
> Jacky Li
--
Sent from:
http://apache-carbondata-dev-mailing-list-archive.1130556.n5.nabble.com/
