[DRILL-5531] Nullable value vectors unnecessarily inherit from BaseDataValueVector

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.8.0
• Assignee: Unassigned
• Reporter: Paul Rogers
• Created: 21/May/17 23:21
• Updated: 15/Feb/23 06:33

Description

Consider a typical nullable value vector: NullableVarCharVector. The members are:

  private final UInt1Vector bits = new UInt1Vector(bitsField, allocator);
  private final VarCharVector values = new VarCharVector(field, allocator);

Inheritance is defined as:

class NullableVarCharVector extends BaseDataValueVector ...

But, notice the members of BaseDataValueVector:

  protected DrillBuf data;

It is confusing that a nullable vector has a data buffer that is never used. Instead, the data is carried by the values member.

Improvements:

• Define a new BaseNullableVector class that does not extend BaseDataValueVector.
• Move the bits member to the new base class rather than declaring it anew in each generated class.
• Adjust member functions to match.