[ARROW-6869] [C++] Dictionary "delta" building logic in builder_dict.h produces invalid arrays

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 0.15.1, 0.16.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/16925
• Assignee: Wes McKinney
• Reporter: Wes McKinney
• Created: 14/Oct/19 01:19
• Updated: 11/Jan/23 07:50
• Resolved: 18/Oct/19 13:50

Description

Looking at the unit tests for the dictionary delta logic – the arrays that are produced by subsequent invocations of Finish yield DictionaryArray instances with partial dictionaries. I think this is misleading (I was surprised to find this while working on ARROW-6861). We should develop a different approach to computing dictionary delta.

Issue Links

• links to: GitHub Pull Request #5687