QUITE: A Query Rewrite System Beyond Rules with LLM Agents

Understand

Query rewrite transforms SQL queries into semantically equivalent forms that run more efficiently.

• Existing approaches mainly rely on predefined rewrite rules, but they handle a limited subset of queries and can cause performance regressions.
• This limitation stems from three challenges of rule-based query rewrite: (1) it is hard to discover and verify new rules, (2) fixed rewrite rules do not generalize to new query patterns, and (3) some rewrite techniques cannot be expressed as fixed rules.
• Motivated by the fact that human experts exhibit significantly better rewrite ability but suffer from scalability, and Large Language Models (LLMs) have demonstrated nearly human-level semantic and reasoning abilities, we propose a new approach of using LLMs to rewrite SQL queries beyond rules.