[LUCENE-8703] Build point writers only when needed on the BKD tree

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 8.x, master (9.0)
• Lucene Fields: New
• Assignee: Ignacio Vera
• Reporter: Ignacio Vera
• Created: 21/Feb/19 08:28
• Updated: 01/Mar/19 06:44
• Resolved: 01/Mar/19 06:44

Description

With the introduction of LUCENE-8699, I have realised the BKD tree uses quite a lot of heap even when it is not needed, for example for 1D points. 

In this issue I propose to create point writers only when needed. In addition I propose to create PointWriters based on the estimated point count given in the constructor.