Problem
GPUKnnFloatVectorQuery.rewrite() can send explicit MULTI_KERNEL searches to cuVS multi-partition search, although that native path rejects MULTI_KERNEL.
Proposed change
Route explicit MULTI_KERNEL through Lucene's per-segment rewrite path so each CAGRA reader executes the supported algorithm. Preserve AUTO, SINGLE_CTA, supported multi-partition behavior, and the selective-filter fallback being developed in #2612.
Add a multi-segment CAGRA-only regression test covering rank-one self matches, exact hit count, unique IDs, and absence of brute-force indexes.
Problem
GPUKnnFloatVectorQuery.rewrite()can send explicitMULTI_KERNELsearches to cuVS multi-partition search, although that native path rejectsMULTI_KERNEL.Proposed change
Route explicit
MULTI_KERNELthrough Lucene's per-segment rewrite path so each CAGRA reader executes the supported algorithm. PreserveAUTO,SINGLE_CTA, supported multi-partition behavior, and the selective-filter fallback being developed in #2612.Add a multi-segment CAGRA-only regression test covering rank-one self matches, exact hit count, unique IDs, and absence of brute-force indexes.