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Databases & Data

The most popular blog posts about databases & data on Hacker News. 138 posts.

2021
35

PostGIS at 20, the Beginning

Twenty years ago today, the first email on the postgis users mailing list (at that time hosted on yahoogroups.com) was sent, announcing the first numbered release of PostGIS. The early history of PostGIS was tightly bound to a consulting company I had started a few years prior, Refractions Research. My first contracts…

37

EBCDIC is incompatible with GDPR

Welcome to acronym city! The Court of Appeal of Brussels has made an interesting ruling. A customer complained that their bank was spelling the customer's name incorrectly. The bank didn't have support for diacritical marks. Things like á, è, ô, ü, ç etc. Those accents are common in many languages. So it was a little…

41

Word-Aligned Bloom Filters

Programmers often need to 'filter out' data. Suppose that you are given a database of users where only a small percentage are 'paying customers' (say 5% or less). You can write an SQL query to check whether a given user is indeed a paying customer, but it might require a round trip to your database … Continue reading…

47

Why SELECT * is bad for SQL performance (2020)

Here’s a list of reasons why SELECT * is bad for SQL performance, assuming that your application doesn’t actually need all the columns. When I write production code, I explicitly specify the columns of interest in the select-list (projection), not only for performance reasons, but also for application reliability…

55

Why do we use R rather than Excel?

I recently had cause to take a beginners course in R - a language I'm fairly familiar with. One of the other students had never used it before, so we were buddied up in order for me to show them the ropes. The first lesson of R is always the same. Read a CSV, manipulate it a bit, draw a graph. We did it all without…

57

Why isn't differential dataflow more popular?

Differential dataflow is a library that lets you write simple dataflow programs and a) then runs them in parallel and b) efficiently updates the outputs when new inputs arrive. Compared to competition like spark and kafka streams , it can handle more complex computations and provides dramatically better throughput and…

58

Replacing Elasticsearch with Rust and SQLite (2017)

Caveat: Elasticsearch is a multi-purpose, distributed, battle-tested, schema-free, log and document storage engine. We’ll be replacing it with a single-purpose, relational schema, me-tested, and custom nginx access log storage engine. Knowing that, let’s begin. Find this project on Github After building my home…

59

I don't think Elasticsearch is a good logging system

I’ve been a heavy user of ElasticSearch for coming up 7 years now. During that time I’ve used it for a few main usecases: A Search Engine, An APM Solution (after NewRelic started being stupidly expensive), a backend for Jaeger, and as a log storage system. In all of those usecases I’ve really pushed ElasticSearch to…