Query Decomposition: Breaking Complex Questions into Sub-Queries
~15 min read
A single complex question often can't be answered by one retrieval pass. Query decomposition breaks it into smaller, independently-answerable sub-queries, retrieves for each, then synthesizes a final answer — a common complement to the core agentic RAG loop.
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Key points
- •Complex, multi-part questions often can't be answered by a single retrieval pass
- •Query decomposition breaks a complex question into smaller, independently-answerable sub-queries, each with its own retrieval
- •A final synthesis step combines individual sub-answers into one coherent answer to the ORIGINAL question — not just concatenation
- •Decomposition typically happens early in the pipeline, before source selection and retrieval begin for each sub-query
- •Most valuable for analytical/comparative/multi-hop questions — adds little value (just extra LLM calls) for simple single-fact questions