How Quail wins: operator ordering, KV pinned in HBM, and tree attention for AI joins

sh_reya · x · 2026-09-25

Quail's speedups come from jointly optimizing planning and inference: it reorders AI operators and pipelines rows so KV cache stays in GPU HBM, batches work to keep the GPU busy, and uses tree attention tricks (à la SpecInfer and Hydragen) to reuse forward-pass work in AI joins. The author argues AI-SQL is a distinct workload — requests known upfront, throughput-oriented, entirely prefill — justifying a specialized inference engine.

Related event: UC Berkeley Open-Sources Quail, an AI-SQL Engine Hitting 1B+ Tokens/min on a Single H100(10 posts)→

Original post →

More from Infra

Infra channel →