# How to resolve a million domains

DevFeed: [How to resolve a million domains](<https://devfeed.tech/articles/how-to-resolve-a-million-domains-38931.md>)

Original publisher: [Read original article](<https://idea.popcount.org/2013-11-28-how-to-resolve-a-million-domains>)

Author: Marek

Published: 2013-11-27T23:00:00Z

Content type: tutorial

Language: en

Sources: [Marek Majkowski](<https://devfeed.tech/sources/marek-majkowski.md>)

Topics: [Concurrency](<https://devfeed.tech/topics/concurrency.md>), [Programming](<https://devfeed.tech/topics/programming.md>), [data](<https://devfeed.tech/topics/data.md>), [Internet](<https://devfeed.tech/topics/internet.md>), [Latency](<https://devfeed.tech/topics/latency.md>), [Protocol (disambiguation)](<https://devfeed.tech/topics/protocol.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [code](<https://devfeed.tech/tags/code.md>), [concurrency](<https://devfeed.tech/tags/concurrency.md>), [data](<https://devfeed.tech/tags/data.md>), [dns](<https://devfeed.tech/tags/dns.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [internet](<https://devfeed.tech/tags/internet.md>), [latency](<https://devfeed.tech/tags/latency.md>), [programming](<https://devfeed.tech/tags/programming.md>)

## AI overview

This article examines the technical challenge of resolving one million domains within a constrained time. It compares DNS resolution approaches and explains how protocol characteristics, blocking calls, and concurrency affect throughput, including an experiment that increased performance with parallel worker goroutines before file-descriptor limits became a bottleneck.

## Source excerpt

How to resolve a million domains Few years ago Alexa started to publish a daily snapshot of top one million domains used on the internet. Using this data I wanted to analyse how the DNS assignments change over time. The plan was simple: - Every day download the Alexa list of top domains. - Every day resolve all the domains. - Do something with the gathered data. - Profit!