A SQL Heuristic: ORs Are Expensive
But this is slow! With 1,000,000 applications and 1000 users uniformly distributed on both columns, it takes over 100ms. 1
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The most popular blog posts about databases & data on Hacker News. 148 posts.
But this is slow! With 1,000,000 applications and 1000 users uniformly distributed on both columns, it takes over 100ms. 1
Durable execution with just postgres.
I analysed almost 2,000 Oscar speeches to discover if the claim that Harvey Weinstein was thanked more often than God is true. Plus, we'll find out which Hollywood icon is bigger than both of them.
Above is a graph that displays the amount of Form Ds filed, where the entity (read: company/firm) name contains the phrases "fund I", "fund II", "fund III", and "fund IV". The x-axis is not the prettiest, but it is broken down by quarter. You can see that the line for "fund I" sees by far the greatest peak around…
A few years back I did a bit of dance music related data visualization over at Lazily Evaluated. My favourite was an analysis of clubs and their lineups using Resident Advisor / RA data, I called it Clubster Analysis. I always wanted to dig into the technical aspects of gathering the data, analyzing it and building…
the psql client version 18 comes with pipelining, which can speed up client-server communication. In this post, let's see how it works and how much can be g...
Missing the Forest for the Sequence Trees.
Rene Schallner (@renerocksai): software engineer turned AI researcher and engineer, in Vienna.
Whither Major Depression?
6.2k words, 29 minutes reading time
An interesting twist in my recent usage of SQLite was the fact that I noticed my research scripts and the database intertwine more. SQLite is unique in that it really lives in-process, unlike standalone database servers. There is a feature to that which does not get used very frequently, but can be indispensable in…
Personal website for some random tidbits I work on
For quite some time now, i have been working on and off on a fully self-hosted search engine , in hope to make it easier to search across Personal data in an end to end manner. Even as individuals, we are hoarding and generating more and more data with no end in sight. Such "personal" data is being stored from local…
In a previous [0] post I’ve discussed why I ditched sea-query and why sql is almostalways the best way to not re-learn something new from the beginning...
Stop deploying broken SQL queries. RegreSQL provides regression testing for PostgreSQL queries with performance baselines and automated warnings.
There comes a time in every software engineer’s life when they come up with a new binary-to-decimal floating-point conversion method. I guess my time has come. I just wrote one, mostly over a weekend: https://github.com/vitaut/zmij .
The data on the page is presented in a hierarchichal structure. The movie page contains a director, a list of genres, a list of actors, and each actor in the list contains a list of characters they played in the movie. You can't sensibly fit all of this into a single flat structure like a relation.
What does a relational database designed specifically for local SSDs look like? Postgres, MySQL, SQLite and many others were invented in the 90s and 00s, the era of spinning disks. A local NVMe SSD has ~1000x improvement in both throughput and latency. Design decisions like write-ahead logs, large page sizes, and…
Benchmarks & Tips for Big Data, Hadoop, AWS, Google Cloud, PostgreSQL, Spark, Python & More...
(or actually they do, but they don’t use this knowledge effectively)Update, April 26, 2025: the address fix for W 6th Ave is live, mostly. Going forward I wish that Google Maps would make it harder…
Is SQLite durable by default? What settings guarantee durability? The documentation and even comments from its creator give conflicting answers.
Integrating my BM25 pandas search library, SearchArray, into BEIR, in order to embarass myself in public.
Thomas Ptacek, a friend and expert witness in this lawsuit summed it up best in the court's hallway while walking within three feet of opposing counsel: "This is fucking stupid" .
Understanding query planner quirks yielded a ~35% speedup.
Every modern exchange is a distributed database in disguise. This article reveals how trading engines transform chaotic streams of buy and sell orders into a perfectly ordered, replayable log, ensuring fairness, determinism, and market data reliability.
As we saw in the opening post, SQLite stores metadata about tables in a special "schema table" starting on page 1. We've been reading records from this…
Pydantic’s JSON loading uses a huge amount of memory; here’s how to reduce it.
AWS Senior Principal Engineers, Niko Matsakis and Marc Bowes, take us inside Aurora DSQL's development: scaling write operations without two-phase commit, overcoming garbage collection hurdles, and embracing Rust for both data and control planes.