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https://issues.apache.org/jira/browse/DRILL-2284?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14635108#comment-14635108
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Hari Sekhon edited comment on DRILL-2284 at 7/21/15 3:15 PM:
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With regards to what is achievable in this ticket because the scope of
describing all these formats is quite large I think it's sufficient for this
ticket to simply print an error for these formats to say "describe is not yet
supported for format <type>".
There should also be a general catch-all condition added where if describe
returns an empty table, print error "Failed to determine schema of <source>"
instead of printing an empty table.
Regarding adding support for these different dynamic formats I've created
individual tickets per storage format that I've bumped in to myself and wanted
a describe command for, including implementation suggestions for how to handle
them since I believe that is why there is not yet any describe support for them:
Describe JSON - DRILL-3526
Describe Parquet - DRILL-3525
Describe MongoDB - DRILL-3524
Describe CSV - DRILL-3529
was (Author: harisekhon):
With regards to what is achievable in this ticket because the scope of
describing all these formats is quite large I think it's sufficient for this
ticket to simply print an error for these formats to say "describe is not yet
supported for format <type>".
There should also be a general catch-all condition added where if describe
returns an empty table, print error "Failed to determine schema of <source>"
instead of printing an empty table.
Regarding adding support for these different dynamic formats I've created
individual tickets per storage format that I've bumped in to myself and wanted
a describe command for, including implementation suggestions for how to handle
them since I believe that is why there not yet any describe support for them:
Describe JSON - DRILL-3526
Describe Parquet - DRILL-3525
Describe MongoDB - DRILL-3524
Describe CSV - DRILL-3529
> Describe table returns no rows for Parquet / JSON / Text
> --------------------------------------------------------
>
> Key: DRILL-2284
> URL: https://issues.apache.org/jira/browse/DRILL-2284
> Project: Apache Drill
> Issue Type: Bug
> Components: Metadata
> Reporter: Abhishek Girish
> Assignee: Steven Phillips
> Priority: Minor
> Fix For: 1.4.0
>
>
> 'Describe' table should either support displaying schema information or fail
> indicating the lack of support for Parquet / JSON / Text
> Currently no rows are returned, which might confuse an end user
> *Parquet/JSON/Text:*
> > describe store_sales;
> +--+
> | |
> +--+
> +--+
> No rows selected (0.07 seconds)
> *Hive:*
> > describe region;
> +-------------+------------+-------------+
> | COLUMN_NAME | DATA_TYPE | IS_NULLABLE |
> +-------------+------------+-------------+
> | r_regionkey | INTEGER | YES |
> | r_name | VARCHAR | YES |
> | r_comment | VARCHAR | YES |
> +-------------+------------+-------------+
> *Views:*
> > describe ship_mode_par_view;
> +-------------+------------+-------------+
> | COLUMN_NAME | DATA_TYPE | IS_NULLABLE |
> +-------------+------------+-------------+
> | * | ANY | NO |
> +-------------+------------+-------------+
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