Andrew Certain Profile picture
21-year Amazon veteran. VP/Distinguished Engineer in AWS in QLDB. All tweets are personal opinions, though some don't even rise to that level of thought. He/his
Iftach Ragoler Profile picture Koushik Profile picture 2 subscribed
Oct 25, 2022 12 tweets 3 min read
I left Amazon/AWS in June, 2022, and it’s time to start working again. I’m not looking for the same kind of role that I held at Amazon/AWS, and this thread attempts to explain what I’m looking for. DMs open/RTs appreciated. My ideal role likely doesn’t exist. I’ve repeatedly led small teams to build ambitious, deeply technical products that had great impact. But I know that such a role often requires massive time and emotional commitment, and my life circumstances don't allow that right now.
Oct 31, 2019 31 tweets 6 min read
My first reaction was "that's dumb - a highway can hold more cars at 20mph than 65mph; it's throughput that matters." Then I read the article and realized that the summary was what was dumb. The actual study was not, and illustrates computer systems concepts, as I'll explain: I've published this thread to my blog, so I ask you to use that link if you want to read on a single page, please don't ask threader apps to compile. blog.tacertain.com/latency-throug…
Aug 26, 2019 44 tweets 11 min read
People dunked on this tweet, saying, in essence, "This isn't 100% correct - you shouldn't pay attention." But that misses the point. The value of any model is that it's simpler than reality so that you can gain insight. Here are the insights I have gained from this model. Fred Brooks first put forth the idea that adding people to a late project makes it later, and stated that the pairwise communication was the real killer. Note that he was only talking about adding people to a late project - more on this later. But first, a digression (or two)!
May 25, 2019 30 tweets 10 min read
If you're wondering what "P-four-nines" means, it's the latency at the 99.99th percentile, meaning only one in 10,000 requests has a worse latency. Why do we measure latency in percentiles?

A thread about how how it came to be at Amazon...

In 2001, I was managing the Performance Engineering team. We were responsible for the performance of the website, and we were frustrated. We were a few engineers fighting against the performance entropy of hundreds of developers adding features to the web site.