Passed a CosmosDB Exam | Voice of the DBA

Passed a CosmosDB Exam

I took the beta exam for Cosmos DB a few months back. I did this as part of the MVP program, as they were asking people to evaluate the exam and give feedback. I’ve lightly used Cosmos DB, but I also thought I might get some practice with the platform and taking an MS test, which I haven’t done in years.

I passed!

I got a note today that the results for DP-420 were in. This is the Designing and Implementing Cloud-Native Applications Using Microsoft Azure Cosmos DB exam, which is way out of my area.

To be fair, I didn’t want to just take this blind, so I spent about a week and a half studying regularly each day, going through the learning path and understanding the different aspects of CosmosDB. It was interesting and confusing, but I acquired a decent understanding of what the platform is and can do.

What I didn’t know were some specifics like how many RU/s might be available for a particularly sized contained. I did, however, learn about the different types of containers, accounts, hierarchies of things, etc.

Feedback

I like the beta exams because you get more than the 5 minutes or so to give feedback, and can do so for many questions. While I think the exams do test some knowledge in most cases, I also think that they can mislead people at times. I also think that some questions are really fact memorization.

For example, if you asked me what is max size of a serverless container, that seems like a reasonable thing to know. If you’re planning an install, you should know that serverless limits things.

However, this is a memorization fact. It’s a documentation thing you can look up in seconds, and by the way, you should. That number could change any day as Cosmos DB evolves.

There were 2-3 questions like that on my exam and I gave that feedback. I don’t have a better question, but knowing that a container is 10GB or 50GB seems like a poor test of knowledge.

There were a few issues I had with wording, but overall the questions weren’t bad, IMHO. They were hard. Unlike many of the other SQL exams, I found most of these to be hard and was unsure of if I really knew the answer.