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https://issues.apache.org/jira/browse/DRILL-836?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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George Chow updated DRILL-836:
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Description:
Drill needs to help users understand the available columns in a given HBase
table's column-family. One way to do this is to implement the DESCRIBE command
for a column-family. The purpose of this is to let Drill do the column
sampling. The mandatory LIMIT clause specifies the sample size so as to
throttle the number of columns returned.
==
Instead of the above narrow proposal, a general mechanism to return complex
types in a JSON string so as to allow client tools (such as the ODBC driver) to
operate on these complex types.
Returning a map as JSON would provide transparency into HBase column-families
and allow the ODBC driver to help surface the names of columns within a
column-family.
Returning an array as JSON would provide transparency into CSV files since that
conveys the number of columns to the ODBC driver.
was:Drill needs to help users understand the available columns in a given
HBase table's column-family. One way to do this is to implement the DESCRIBE
command for a column-family. The purpose of this is to let Drill do the column
sampling. The mandatory LIMIT clause specifies the sample size so as to
throttle the number of columns returned.
Summary: Drill needs to return complex types (e.g., map and array) as a
JSON string (was: Implement "DESCRIBE hbase.table.column-family LIMIT n")
> Drill needs to return complex types (e.g., map and array) as a JSON string
> --------------------------------------------------------------------------
>
> Key: DRILL-836
> URL: https://issues.apache.org/jira/browse/DRILL-836
> Project: Apache Drill
> Issue Type: Bug
> Reporter: George Chow
>
> Drill needs to help users understand the available columns in a given HBase
> table's column-family. One way to do this is to implement the DESCRIBE
> command for a column-family. The purpose of this is to let Drill do the
> column sampling. The mandatory LIMIT clause specifies the sample size so as
> to throttle the number of columns returned.
> ==
> Instead of the above narrow proposal, a general mechanism to return complex
> types in a JSON string so as to allow client tools (such as the ODBC driver)
> to operate on these complex types.
> Returning a map as JSON would provide transparency into HBase column-families
> and allow the ODBC driver to help surface the names of columns within a
> column-family.
> Returning an array as JSON would provide transparency into CSV files since
> that conveys the number of columns to the ODBC driver.
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