[DRILL-6810] Disable NULL_IF_NULL NullHandling for functions with ComplexWriter

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.14.0
• Fix Version/s: 1.15.0
• Labels: doc-impacting ready-to-commit
• Assignee: Bohdan Kazydub
• Reporter: Bohdan Kazydub
• Reviewer: Arina Ielchiieva
• Created: 23/Oct/18 08:09
• Updated: 13/Aug/19 08:58
• Resolved: 02/Nov/18 21:23

Description

Currently NullHandling.NULL_IF_NULL is allowed for UDFs with @Output of type org.apache.drill.exec.vector.complex.writer.BaseWriter.ComplexWriter but no null handling is performed for the kind of functions which leads to confusion. The problem is ComplexWriter holds list/map values and Drill does not yet support NULL values for the types (there is an issue to allow null maps/lists in DRILL-4824).
For such functions support for NULL_IF_NULL will be disabled, as it is done for aggregate functions, and NullHandling.INTERNAL should be used instead.

Issue Links

• links to: GitHub Pull Request #1509