Applications and use cases
These are the topics in this section, each on its own page with a stable path you can bookmark or share.
What topics are covered in this section?
- What is semantic search?
- What is recommendation-system retrieval?
- What is candidate generation and ranking?
- What is two-stage reranking?
- What is image similarity search?
- What is face and instance retrieval?
- What is duplicate detection?
- What is cross-modal retrieval?
- What is a joint embedding space?
- What is retrieval-augmented generation (RAG)?
- What is passage embedding?
- What is document chunking?
- What is cross-encoder reranking?
- What is multi-vector document retrieval?
- What are user and item embeddings?
- What is popularity skew in recommendations?
- What is business-rule filtering?
- What is fresh-item insertion in a recommender system?
- What is text-to-image retrieval?
- What is update freshness in retrieval systems?
Applications and use cases show where HNSW shows up in products: semantic search, recommendations, images, RAG, chunking, reranking, and freshness under business rules.
What product patterns rely on approximate neighbors?
Semantic search and RAG embed passages or chunks and retrieve context for people or generators. Recommendations use user and item embeddings with candidate generation, ranking, popularity skew, and fresh-item insertion. Image, face, duplicate, and text-to-image retrieval live in visual or joint embedding spaces. Cross-encoders and multi-vector document retrieval add second-stage ranking. Business-rule filtering and update freshness couple ANN to application policy.
HNSW is usually the retrieval engine inside these loops, not the whole product.
How does Weaviate support these patterns?
Weaviate provides vector, keyword, and hybrid search, filtered HNSW, multi-tenancy, and model integrations for embedding and reranking – matching the application glossary’s building blocks. Chunking and passage embedding remain application responsibilities that strongly affect recall. Part IX walks these use cases in curriculum form.
Application terms keep algorithm tuning tied to user outcomes.
What should you read next?
Start with semantic search, RAG, candidate generation, and hybrid-related filtered pages, then Part IX chapters for your domain. For infrastructure under the app, see persistence and scaling hubs.
This section connects HNSW to product work. Next, open “What is retrieval-augmented generation (RAG)?” or Part IX’s semantic-search chapter, then chunking and reranking terms when quality issues sit above the index.