When RAG Meets Query Planning: Logical Query Trees for Resolving Exploratory Reasoning Problems
This work addresses the limitations of traditional retrieval-augmented generation (RAG) in handling highly uncertain exploratory reasoning problems (ERPs), where it is prone to retrieval noise and error propagation due to the absence of an end-to-end query planning mechanism. To overcome this, the authors propose PlanRAG, a novel framework that introduces database-inspired query planning into RAG for the first time. PlanRAG formalizes complex natural language queries as logical query trees (LQTs) and constructs high-quality LQTs using a multidimensional cost model combined with dynamic programming. It then executes a concurrent, iterative pipeline of retrieval, rewriting, aggregation, and generation, enabling parallel processing of subqueries. Evaluated on the newly introduced WikiWeb-ERP dataset, PlanRAG significantly outperforms existing iterative and graph-based RAG approaches, demonstrating its effectiveness and superiority in exploratory reasoning tasks.