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From "Hyunsik Choi (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (TAJO-256) Support data cube (Umbrella)
Date Wed, 16 Oct 2013 14:37:44 GMT

    [ https://issues.apache.org/jira/browse/TAJO-256?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13796836#comment-13796836

Hyunsik Choi commented on TAJO-256:

Sounds interesting. Sample-based query planning will be widely used in various query types.

Sampling an input data should be executed as a distributed query. They should work transparently
to users. However, the current Tajo does not support a internal mechanism to submit a distributed
query for sampling without disclosing query executions. It would be also a nice idea to design
and implement a sampling and analysis system to collect statistics information with various
aspects. In addition, the sampling results will be available until an input table is changed.
As a result, it will be very useful if the sampling results are kept in catalog system. For
this, we may need more elaborate catalog system that maintains and keeps statistics information.

For them, it would be a good starting point to refer other database systems.

> Support data cube (Umbrella)
> ----------------------------
>                 Key: TAJO-256
>                 URL: https://issues.apache.org/jira/browse/TAJO-256
>             Project: Tajo
>          Issue Type: New Feature
>          Components: catalog, distributed query plan, parser
>            Reporter: Jihoon Son
>            Assignee: Jihoon Son
>             Fix For: 0.3-incubating
> This issue includes follows sub issues
> * SQL support of group by extensions (GROUPING SETS, CUBE, ROLLUP)
> * Query execution of group by extensions
> * GROUPING() function
> * Data cube materialization process
> * Cube schema maintenance
> * Sample-based cost estimation

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