You are viewing a plain text version of this content. The canonical link for it is here.

Posted to issues@carbondata.apache.org by "dhatchayani (JIRA)" <ji...@apache.org> on 2019/02/15 07:15:00 UTC

[jira] [Updated] (CARBONDATA-3293) Prune for count(*) improvement

     [ https://issues.apache.org/jira/browse/CARBONDATA-3293?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

dhatchayani updated CARBONDATA-3293:
------------------------------------
    Description: 
Problem:

(1) Currently for count(*), the prune is same as select * query.  Blocklet and ExtendedBlocklet are formed from the DataMapRow and that is of no need.

 

Solution:

We have the blocklet row count in the DataMapRow itself, so it is just enough to read the count. With this count(*) query performance can be improved.

> Prune for count(*) improvement
> ------------------------------
>
>                 Key: CARBONDATA-3293
>                 URL: https://issues.apache.org/jira/browse/CARBONDATA-3293
>             Project: CarbonData
>          Issue Type: Improvement
>            Reporter: dhatchayani
>            Assignee: dhatchayani
>            Priority: Major
>
> Problem:
> (1) Currently for count(*), the prune is same as select * query.  Blocklet and ExtendedBlocklet are formed from the DataMapRow and that is of no need.
>  
> Solution:
> We have the blocklet row count in the DataMapRow itself, so it is just enough to read the count. With this count(*) query performance can be improved.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)