[LUCENE-10620] Can we pass the Weight to Collector?

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 9.3
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Adrien Grand
• Created: 16/Jun/22 09:53
• Updated: 28/Aug/22 16:42
• Resolved: 23/Jun/22 16:04

Description

Today collectors cannot know about the Weight, and thus they cannot leverage Weight#count. IndexSearcher#count works around it by extending TotalHitCountCollector in order to shortcut counting the number of hits on a segment via Weight#count whenever possible.

It works, but I would prefer this shortcut to work for all users of TotalHitCountCollector. For instance the faceting module creates a MultiCollector over a TotalHitCountCollector and a FacetCollector, and today it doesn't benefit from quick counts, which would enable it to only collect matches into a FacetCollector.

I'm considering adding a new Collector#setWeight API to allow collectors to leverage Weight#count. I gave TotalHitCountCollector as an example above, but this could have applications for our top-docs collectors too, which could skip counting hits at all if the weight can provide them with the hit count up-front.

Issue Links

• links to: GitHub Pull Request #964