[LUCENE-9845] Improve encoding of HNSW graph offsets

• Type: Wish
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Michael Sokolov
• Created: 15/Mar/21 21:25
• Updated: 28/Aug/22 16:18

Description

Today we use a simple long[] to encode the offset of each document's array of neighbors in the HNSW graph. Instead we should use a data structure that is optimized for encoding an increasing numeric array, like   monotonic PackedInts