[DRILL-836] Drill needs to return complex types (e.g., map and array) as a JSON string

• Type: New Feature
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.4.0
• Fix Version/s: 0.4.0
• Component/s: Execution - Relational Operators, Execution - RPC
• Assignee: Aditya Kishore
• Reporter: George Chow
• Created: 24/May/14 08:16
• Updated: 29/Sep/14 06:18
• Resolved: 16/Jun/14 21:33

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.

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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.

Issue Links

• relates to: DRILL-1060 Support ComplexToJson for Array Data Type