I was working with CombinedQuerySearchHandler (in solr 10.1.0.rc2) today and noticed that it reports numFound as the largest sub-query's hit count, not the size of the fused result. Shouldn't it instead be the number of distinct documents in the combined result, which is the union of the sub-queries?
Here's a reproduction: SOLR=http://localhost:8983/solr/demo curl -s "$SOLR/config" -H 'Content-Type: application/json' -d '{ "add-searchcomponent": {"name": "combined_query", "class": "solr.CombinedQueryComponent"}, "add-requesthandler": {"name": "/hybrid", "class": "solr.CombinedQuerySearchHandler"} }' 3 cat docs, 2 dog docs, no overlap curl -s "$SOLR/update?commit=true" -H 'Content-Type: application/json' -d '[ {"id": "1", "subject_s": "cat"}, {"id": "2", "subject_s": "cat"}, {"id": "3", "subject_s": "cat"}, {"id": "4", "subject_s": "dog"}, {"id": "5", "subject_s": "dog"} ]' curl -s "$SOLR/hybrid" -H 'Content-Type: application/json' -d '{ "queries": { "cats": {"lucene": {"query": "subject_s:cat"}}, "dogs": {"lucene": {"query": "subject_s:dog"}} }, "params": { "combiner": true, "combiner.query": ["cats", "dogs"], "combiner.algorithm": "rrf", "fl": "id", "rows": 10 } }' Expected `numFound: 5`, the same as `/select?q=subject_s:cat OR subject_s:dog`, which returns `numFound: 5, numFoundExact: true`. Actual {"response": {"numFound": 3, "start": 0, "numFoundExact": false, "docs": [{"id": "4"}, {"id": "1"}, {"id": "5"}, {"id": "2"}, {"id": "3"}]}} The response returns five documents but reports `numFound: 3`.
