How Modern SQL Databases Come up with Algorithms that You Would Have Never Dreamed Of by Lukas Eder

Devoxx · 55K views · 2017 · 50:31

Open on YouTube

Databases & storagetalk

Why Hacker News recommends it

HN commenters recommend it to developers unfamiliar with how much leverage and intelligence there is in a SQL database.

What it is

Lukas Eder's Devoxx talk on how modern cost-based SQL optimizers rewrite and plan queries in ways developers would not expect. It argues that declarative SQL, used well, can run complex queries very fast.

Recommended by 3 HN commenters across 3 different months, 2019 to 2023.

What Hacker News said

Recommends nerdbaggy · 2020-05 · on “Medium-hard SQL interview questions”

I use to think that too. This is a good talk about how smart SQL query engines are. It is an hour though [this video]

Recommends loudlambda · 2022-02 · on “A Hairy PostgreSQL Incident”

I would suggest that learning SQL (the syntax) isn't the crux--it's just syntax you learn over time based off need, just like learning python--what you need is motivation. I'd suggest watching this video to get a flavor of how much leverage using the database can give you: [this video] If the database can make you more productive and more efficient and make your life easier, you now have incentive to use it more. Another thing that took my use of databases to the next level, was using PostGraphile ( [LINK] ). It takes a PostgreSQL database and provides a GraphQL endpoint for it. Use that as your only backend. You can use PostgreSQL row-level security to do access control (who can see or modify wh

Recommends lukaseder · 2023-09 · on “Permazen: Language-natural persistence to KV stores”

> This may be more intuitive for some developers, especially those that don't use SQL all the time. I tend to recommend my famous talk to such developers: [this video]

Cites jodrellblank · 2019-05 · on “Joins In Steps”

This talk ("How Modern SQL Databases Come up with Algorithms that You Would Have Never Dreamed Of by Lukas Eder" [this video] ) is not particularly gripping, but he does claim that modern database engines will ignore indexes if they estimate it will be faster to read all the data than it is to access the index first then read the relevant data. And that Oracle can have multiple execution plans and switch between them mid-query if the first one isn't working out as expected. Could this be a rare case of the mythical sufficiently smart compiler having more information at runtime than the programmer has at coding time, and that if you could hint which index to use, the trade off would be that you'd

Cites taffer · 2019-11 · on “Modern Data Practice and the SQL Tradition”

> further, afaik there's no assignment nor iteration in SQL That was until CTEs were introduced in SQL:1999 > it's not a programming language at all. It's a.. query language. The two are not mutually exclusive. SQL is used to tell a computer what to do, and it is very powerful at it: [this video]

Cites lukaseder · 2022-08 · on “Parsing SQL”

>Totally agree. Lukas Eder has some nice presentations about it. Thanks for the shout out! For the record, that's probably the referenced talk: [this video]