[LUCENE-10062] Explore using SORTED_NUMERIC doc values to encode taxonomy ordinals for faceting

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 9.0, 10.0 (main)
• Component/s: modules/facet
• Lucene Fields: New
• Assignee: Greg Miller
• Reporter: Greg Miller
• Created: 23/Aug/21 23:36
• Updated: 28/Aug/22 16:24
• Resolved: 23/Nov/21 14:03

Description

We currently encode taxonomy ordinals using varint style packing in a binary doc values field. I suspect there have been a number of improvements to SortedNumericDocValues since taxonomy faceting was first introduced, and I plan to explore replacing the custom binary format we have today with a SORTED_NUMERIC type dv field instead.

I'll report benchmark results and index size impact here.

Issue Links

• links to: GitHub Pull Request #264
• links to: GitHub Pull Request #443