~/talk

Late Interaction Retrieval in Practice: Implications for OpenSearch-Based Search Systems

Talkat OpenSearchCon Europe 2026 · on Thursday, 2026-04-16· at 12:00· Bohemia 3· [large-language-models, machine-learning]
links:none on file
slides:none on file

Late interaction retrieval is practical as a rescoring stage in OpenSearch: documents store one pooled canonical vector for ANN indexing and separate token vectors kept as nonindexed objects, queries pool a query vector then expand candidates 10x and apply token-level max-sum scoring. A recent cold bandit algorithm reduces token comparisons and reports about 5x fewer computations with nDCG@10 unchanged and overlap@10 >0.9. OpenSearch 3.3 adds a native late-interaction score field and mappings for canonical + multivector storage.

AI-written summary · about

  1. 0:00Late interaction retrieval intro
  2. 1:03Three retrieval interaction levels
  3. 7:03Optimization for late interaction
  4. 8:33Cold bandit algorithm
  5. 13:54Late interaction in OpenSearch
  6. 16:40What’s coming next in OpenSearch
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