1.5.4 · Lesson 20 of 28
Advanced search and reranking
Improve retrieval relevance beyond basic vector similarity.
WHAT
Improve retrieval relevance beyond basic vector similarity.
Keyword search
Good for:
- exact names
- IDs
- product codes
- legal terms
- error codes
Vector search
Good for:
- semantic meaning
- paraphrases
- conceptual similarity
Hybrid search
Combine both:
Query
├── Keyword Search
└── Vector Search
↓
Combined Results
↓
Reranker
↓
Final ContextReranking
A reranker evaluates retrieved candidates and reorders them by relevance.
AWS
- Amazon OpenSearch Service
- Amazon Bedrock reranking capabilities
- Bedrock Knowledge Bases
EXAM TRAP
If exact terms matter, pure semantic search may not be enough.
Hybrid retrieval can be better.
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Key points
- Improve retrieval relevance beyond basic vector similarity.
Exam focus
If exact terms matter, pure semantic search may not be enough. Hybrid retrieval can be better.