[HIVE-20287] Document the differences between managed and external tables

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: Documentation
• Assignee: Lars Francke
• Reporter: Lars Francke
• Created: 01/Aug/18 10:15
• Updated: 02/Nov/18 12:28
• Resolved: 02/Nov/18 12:28

Description

We should document all the differences between managed and external tables. I need everyone's help for that though.

This is what I know:

• ARCHIVE/UNARCHIVE - DDLTask - Only works for managed tables
• TRUNCATE - DDLSemanticAnalyzer - Only works for managed tables
• MERGE/CONCATENATE - HiveRelOpMaterializationValidator - Only works for managed tables
• Constraints - DDLSemanticAnalyzer -  (NOT NULL, DEFAULT, CHECK, only RELY ist allowed)
• IMPORT - ImportSemanticAnalyzer - This has some wild restrictions I didn't follow for external tables
• Query Results Caching - https://issues.apache.org/jira/browse/HIVE-18513 SemanticAnalyzer
   
  Hortonworks has extra documentation listing these things:
• Query cache
• Materialized views, except in a limited way
• Default statistics gathering
• Compute queries using statistics
• Automatic runtime filtering
• File merging after insert
   
  It'd be great if someone (from Hortonworks or otherwise) could elaborate on those.