[LUCENE-10250] Add hierarchical labels to SSDV facets

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 9.1, 10.0 (main)
• Component/s: modules/facet
• Labels: discussion
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Marc D'Mello
• Created: 22/Nov/21 22:10
• Updated: 28/Aug/22 16:30
• Resolved: 10/Jan/22 17:36

Description

Hi all,

I recently added a new benchmarking task to luceneutil to count facets on a random word chosen from each document which would give us a very high cardinality facet benchmarking compared to the faceting benchmarks we already had. After being merged, mikemccand pointed out some interesting results in the nightly benchmarks where the BrowseRandomLabelSSDVFacets task was much faster than the BrowseRandomLabelTaxoFacets task.

I was thinking that using SSDV facets instead of taxonomy facets for our use case at Amazon Product Search could potentially lead to some increases in QPS and decreases in index size, but the issue is we use hierarchical labels, and as I understand it, SSDV faceting only supports a 2 level hierarchy as of today. This leads to my question of why is there a limitation like this on SSDV facets? Is hierarchical labels just a feature that hasn't been implemented in SSDV facets yet, or is there some more complex reason that we can't add hierarchical labels to SSDV facets?

Thanks!

Issue Links

• links to: GitHub Pull Request #509
• links to: GitHub Pull Request #595