Name: Meta Case Study - Debugging A Massive Production Issue
Uploaded: 2023-09-06T20:30:37+00:00
Duration: 6 min 10 s
Description: Here we go through an example bug at Meta

Meta Case Study - Debugging A Massive Production Issue

Here we go through an example bug at Meta. Given the information, we need to figure out what kind of root cause is behind the issue. This case study shows:
- Why it's important to understand the blast radius of a bug
- How knowing the context behind a bug can help you locate the problem area
- The value of having robust analytics

This video is a clip from our debugging masterclass. You can watch it here: [[Masterclass] How To Become A Debugging Master And Fix Issues Faster](https://www.jointaro.com/lesson/ioR6WzamAIUTpySLAr7o/masterclass-how-to-become-a-debugging-master-and-fix-issues-faster/)

Related resources:
- [[Case Study] Solving A Multi-Million $$ Instagram Bug](https://www.jointaro.com/lesson/WYk4J05iBqOuPtD0CYKX/case-study-solving-a-multi-million-dollardollar-instagram-bug/)
- ["How can I become more independent and better at unblocking myself with tricky technical issues?"](https://www.jointaro.com/question/QhqQQGrDgFjZbqohpKe0/how-can-i-become-more-independent-and-better-at-unblocking-myself-with-tricky-technical-issues/)
- ["What is the effective way to understand new repository in order to make the required changes in that repo?"](https://www.jointaro.com/question/KoxB3UU2zWC9pdYU6Rx0/what-is-the-effective-way-to-understand-new-repository-in-order-to-make-the-required-changes-in-that-repo/)

Here we go through an example bug at Meta

[Masterclass] How To Become A Debugging Master And Fix Issues Faster

There will always be bugs, and this only becomes more and more true as your product gets bigger. In this video, we go deep into the often underrated software engineer skill of debugging.

Here are the core points:
- **Bugs are a source of growth** - So many engineers see having to fix issues as merely frustration, an obstacle getting in the way of their feature work. This is a toxic mentality to have that holds back your growth. Feature work isn't the only way to move a product forward, and at the end of the day, your team has to come together to uphold the integrity of its systems. Being a champion in that process is a powerful way to get to senior+ levels.
- **Do your research** - When you get a bug, don't just dive in and start mucking around in the code. Figure out the exact repro steps and go through the flow multiple times to really get it. Detail the blast radius by understanding attributes like when the issue popped up, how many users it affected, and what versions of your software experience the problem. Spend at least 15-30 minutes expanding the context behind the bug.
- **Understand the end-to-end flow** - Every outcome in software is a series of steps: When there's a legitimate bug, it simply means that one (maybe several) of those steps are now broken. Before you start seriously debugging, build up this mental model of the overall ecosystem behind the bug - Ask your teammates if you need help with this. This mental model will serve as the foundation of your debug process.
- **Maintain a debug diary** - Document every step of your journey as you're debugging. This will prevent you from trying the same hypothesis twice and makes it much easier for you to hand off the bug if necessary. This context will allow the new person to easily "download" everything you did and pick up where you left off. This writing will also help you a lot come performance review time when you want to claim credit for the fix.
- **Retrospect** - An ounce of prevention is worth a pound of cure. After every bug resolution, do some amount of thinking around how you can prevent similar issues from cropping up in the future. This is especially important with massive bugs that inflicted a lot of damage. In those scenarios, write-up a post-mortem and discuss it with your team.

Related resources:
- [[Case Study] Solving A Multi-Million $$ Instagram Bug](https://www.jointaro.com/lesson/WYk4J05iBqOuPtD0CYKX/case-study-solving-a-multi-million-dollardollar-instagram-bug/)
- ["How can I root cause bugs faster?"](https://www.jointaro.com/question/PSv7aYI70VwaDsoRgMyW/how-can-i-root-cause-bugs-faster/)
- ["I'm trying to fix a P1 bug, but some relevant code is owned by another team. Unsure about ownership and how to proceed."](https://www.jointaro.com/question/ZRneLgwmrM2JLCrGn5Rz/im-trying-to-fix-a-p1-bug-but-some-relevant-code-is-owned-by-another-team-unsure-about-ownership-and-how-to-proceed/)

If you want to become a better coder in general, check out our masterclass here: [[Masterclass] How To Write Better Code Faster As A Software Engineer](https://www.jointaro.com/lesson/iYpRj8XfyzCSaTYnce3y/masterclass-how-to-write-better-code-faster-as-a-software-engineer/)