https://yaooqinn.github.io/tags/sql-rewrite/ Recent content in Sql-Rewrite on Kent Yao Hugo -- 0.157.0 en-us Wed, 27 May 2026 00:00:00 +0000 https://yaooqinn.github.io/posts/query-engines/rule-rewrite-blindspot-dsb/ Wed, 27 May 2026 00:00:00 +0000 https://yaooqinn.github.io/posts/query-engines/rule-rewrite-blindspot-dsb/ On TPC-H 10GB, a state-of-the-art learned rewriter cuts mean execution time from 69.84s to 37.57s — a 46% win. On DSB 10GB, the same rewriter takes 32.62s to 31.93s — a 2.1% non-event. The gap isn’t query difficulty; it’s whether the benchmark is in the rewriter’s training distribution. “Rule-based systems are stable and reliable” is often a benchmark artifact, not an engineering fact. https://yaooqinn.github.io/posts/query-engines/llm-only-rewrite-doesnt-work/ Tue, 26 May 2026 00:00:00 +0000 https://yaooqinn.github.io/posts/query-engines/llm-only-rewrite-doesnt-work/ On TPC-H 10GB, asking GPT-4o to rewrite SQL takes mean execution time from 78.81s down to 74.92s — almost nothing. Swap in an open 14B model, feed it plans, add a reward, fine-tune once, and the same workload drops to 29.67s. Whether LLMs can help SQL rewriting is not a question about model strength; it’s a question about whether you’re willing to give the model the signals it actually needs.