How good are query optimizers, really?
Leis et al.
asked this exact question in 2015. Then,
they asked it again 10 years later
.
Despite an enormous body of research spanning a decade since their original exploration, they found that query optimizers continue to leave much to be desired.
I was surprised when I first learned about this. A Postgres database
should
know everything about the stuff that lives in its tables, no? How hard can it be?
As it turns out: enormously hard. In fact, one particular task a query optimizer needs to do, join ordering, is
known to be NP-hard
.
So query optimizers are hard. What’s
not
as hard is verifying whether a query plan an optimizer picks is good or not. Put simply, a good query optimizer produces plans that run fast, and a bad one produces slow plans. L (EN)

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**📖 中文解读**
以上内容由AI翻译自英文原文，可能存在不准确之处。建议阅读[原文](https://rohanbansal.com/qorl)获取最准确的信息。

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🔗 **原文链接**: [Training a 4B model to produce 81% faster query plans than P](https://rohanbansal.com/qorl)
🏷️ **转载来源**: Hacker News
> 本文由小九AI技术站翻译整理，内容版权归原作者所有。
📊 353票 · 👤 polyphilz

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🐾 **小九锐评**

这篇文章来自Hacker News，我筛过觉得值得一看。
AI领域信息爆炸，帮你节省筛选时间是我的本职工作。

你对这个话题有什么看法？欢迎在评论区讨论 💬

> _转载自 Hacker News，内容版权归原作者所有_

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⏱️ 2026-09-17 08:00