http://apache-carbondata-dev-mailing-list-archive.168.s1.nabble.com/Discussion-Support-Secondary-Index-on-Carbon-Table-tp91074p91077.html
> Hi Community,
>
> Currently we have datamaps like,* default datamaps* which are block and
> blocklet and *coarse grained datamaps* like bloom, and *fine grained
> datamaps* like lucene
> which helps in better pruning during query. What if we introduce another
> kind of datamap which can hold blockletId as index? Initial level, we call
> it as index which
> will work as a child table to the main table like we have MV in our current
> code.
>
> Yes, lets introduce the secondary index to carbon table which will be the
> child table to main table and it can be created on column like we create
> lucene datamap,
> where we give index columns to create index. In a similar way, we create
> secondary index on column, so indexes on these column will be blocklet IDs
> which will
> help in better pruning and faster query when we have a filter query on the
> index column.
>
> Currenlty we will take it as index table and then later part we will make
> it inline to datamap interface.
>
> So design document is attached in JIRA, please give your suggestion/inputs.
>
> JIRA Link: CARBONDATA-3680
> <
https://issues.apache.org/jira/browse/CARBONDATA-3680>
>
> Thanks & Regards,
> Indhumathi M
>