[HIVE-6632] ORC should be able to only read needed fields in a complex column

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Yin Huai
• Created: 12/Mar/14 16:49
• Updated: 12/Mar/14 16:50

Description

Currently, we use a string of ids to record needed columns. However, this string cannot record needed fields of a complex column. Although ORC decomposes a complex column to multiple sub-columns, it has to load the entire complex column if only a single field of this complex column is needed.