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Selecting a vector store for Amazon Bedrock Knowledge Bases

AWS Machine Learning · September 17, 2026

Unlocking optimal performance and cost efficiency for retrieval-augmented generation (RAG) applications hinges critically on your choice of vector store. This AWS Machine Learning analysis meticulously evaluates three prominent AWS vector store options—Amazon OpenSearch Service, Amazon Aurora PostgreSQL with pgvector, and Amazon S3 Vectors—specifically in the context of Amazon Bedrock Knowledge Bases. The team provides benchmarks and a practical framework for selecting the most suitable store based on various RAG use cases, detailing how each impacts factors like retrieval speed, scalability, and operational expense. For developers and operators, this directly translates into informed decision-making that can significantly impact project viability and user experience. Consider a small e-commerce shop in Austin, Texas, looking to deploy a Bedrock-powered chatbot for customer service. Choosing S3 Vectors might offer the simplest, most cost-effective solution for a modest product catalog and infrequent queries, avoiding the overhead of managing a database. Conversely, a logistics startup in Chicago building a RAG application to analyze complex shipping manifests and provide real-time updates to clients might find Aurora PostgreSQL with pgvector offers the balance of structured data management and vector search performance needed for sophisticated, frequently updated knowledge bases. Even an internal IT team at a mid-sized financial firm in New York City, developing a secure internal documentation search tool, could leverage OpenSearch Service for its robust indexing and advanced search capabilities, ensuring rapid, precise information retrieval from a vast and constantly evolving data corpus. The practical implication here is a tangible guide to sidestep common pitfalls of over-provisioning or under-performing infrastructure for your AI initiatives. It equips you to match technical requirements with cost-effective solutions, ensuring that your Bedrock Knowledge Bases deliver the desired impact without unnecessary expenditure or complexity. This analysis empowers you to build smarter, more efficient AI-driven products and services, whether you are a solo founder or part of a larger enterprise. To put this into immediate practice, identify one current or prospective RAG application in your workflow that relies on Bedrock Knowledge Bases. Spend an hour this week sketching out its core requirements: data volume, query frequency, latency tolerance, and budget constraints. Then, cross-reference these against the capabilities and cost profiles of OpenSearch, Aurora with pgvector, and S3 Vectors to determine which aligns best, even if you’re just running a quick proof-of-concept.