A traditional Bavarian Hefeweizen: medium body, cloudy, malty, and spicy, with a smooth mouth-feel and dense, whipped-cream head.

At Teem, we aim for zero down-time deploys; so, one of the most important things we must validate is that things will not break mid-deploy!

The most sensitive step of the deploy process is the changes to our database. Prior to the automation I am about to describe, validation of the database migrations required specialized knowledge about Postgres, the changes to the application model, load on the database for that model, and a bit of general experience. This obviously slows down reviews and subsequently deploys. Worse, it was simply too easy to miss problem migrations when depending on only peer reviews. To make our lives easier we created a series of validation checks to ensure that each database migration will be backwards compatible.

How do we build a fast API against database models with foreign keys and many- to-many relationships? If you do nothing you get what I call the “waterfall of doom”. At some point in the past someone told me or I read that “joins are effectively free in Postgres”. While this might be somewhat true when you are writing all of the SQL and can control every part of your query; I have recently found that when the database gets big enough and you are using the Django ORM, joins aren’t free and less can be more!

The other day I was having lunch with a friend when he asked what resources I use to learn about management and tech leadership in general. I will share some recommendations at the end, but my answer to him got me thinking about my philosophy around management and how to be good at it, which is what I really want to share here.

TL;DR: be a multiplier for your team and reduce friction.

I just finished my winter beer. I usually do one dark spicy beer for the winter season. Last year was the “Better Not Pout Stout”, this year is the less excitingly named “Spicy Winter Porter”.


Welcome! This is just a test post, a proof of life.

Lucas Roesler

I am director of engineering at teem.com and an ex-mathematician. I have worked on web applications, algorithms for image analysis, machine learning problems, and pure math research.

Director of Engineering

Utah, USA