Episode 139 - RAG is Expensive but is it really

🧠 What RAG Actually DoesRAG enhances LLMs by retrieving relevant external information (e.g. from documents or databases) at query time, then feeding that into the prompt. This allows the LLM to answer with up-to-date or domain-specific knowledge without retraining.💸 Is RAG Expensive?Yes, it can be — especially if:* You repeatedly reprocess large documents for every query.* You use high token counts to include raw content in prompts.* You rely on real-time parsing of files (e.g. PDFs or Excel) without preprocessing.This is where vector storage and embedding optimization come in.📦 Role of Vector StorageInstead of reloading and reprocessing documents every time:* Documents are chunked into smaller segments.* Each chunk is converted into a vector embedding.* These embeddings are stored in a vector database (e.g. FAISS, Pinecone, Weaviate).* At query time, the user’s question is embedded and matched against stored vectors to retrieve relevant chunks.This avoids reprocessing the original files and drastically reduces cost and latency⚙️ Efficiency StrategiesHere’s how to make RAG more efficient:StrategyDescriptionBenefitVector StorageStore precomputed embeddingsAvoids repeated parsing and embeddingANN IndexingUse Approximate Nearest Neighbor searchFast retrieval from large datasetsQuantizationCompress embeddings (e.g. float8, int8)Reduces memory footprint with minimal accuracy lossDimensionality ReductionUse PCA or UMAP to reduce vector sizeSpeeds up search and lowers storage costContextual CompressionFilter retrieved chunks before sending to LLMReduces token usage and cost Get full access to Just Five Mins! at www.justfivemins.com/subscribe