[DRILL-7610] Allow user to specify table schema in Metastore

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.17.0
• Fix Version/s: 1.18.0
• Assignee: Vova Vysotskyi
• Reporter: Paul Rogers
• Created: 27/Feb/20 01:53
• Updated: 12/May/20 13:42
• Resolved: 23/Mar/20 11:52

Description

The Drill Metastore will infer the schema of a table while gathering stats. Unfortunately, this creates a chicken-and-egg problem. Some files need the Metastore because the schema is ambiguous. Such data won't even scan correctly without such information. Classic JSON example:

{a: 10} {a: 10.1}

In these cases, the user should first define the table schema, then run the ANALYZE TABLE commands. In such cases, Drill should not attempt to change the type information (since the actual data is ambiguous.)