[
https://issues.apache.org/jira/browse/DRILL-1061?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14075688#comment-14075688
]
Jacques Nadeau commented on DRILL-1061:
---------------------------------------
Fixed by caa8b78 or earlier
> Add or modify Optiq rule such that two projects involving complex JSON
> objects should not be collapsed into one.
> ------------------------------------------------------------------------------------------------------------------
>
> Key: DRILL-1061
> URL: https://issues.apache.org/jira/browse/DRILL-1061
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Jinfeng Ni
> Assignee: DrillCommitter
> Fix For: 0.4.0
>
> Attachments: DRILL-1061.patch
>
>
> Currently, Drill could not nest a function whose output is a complex JSON
> object into another function directly. For instance,
> select foo.mycol.x from (
> select convert_from('{ x : [1,2], y : 100 }', 'JSON') as mycol
> from cp.`tpch/nation.parquet`) as foo(mycol);
> select convert_to(foo.mycol.x, 'JSON') from (
> select convert_from('{ x : [1,2], y : 100 }', 'JSON') as mycol
> from cp.`tpch/nation.parquet`) as foo(mycol);
> Optiq will merge the project in the out subquery with the project in the
> inner subquery into one project expression. This cause issues in Drill side.
> In stead, we should add or modify Optiq rule so that the two projects will
> stay where they are, and evaluate the convert_from () first and produce a
> record batch. The second project will read from the record batch, and produce
> its output.
> Doing that will enable Drill to use out / inner subquery to refer the complex
> JSON object .
--
This message was sent by Atlassian JIRA
(v6.2#6252)
