Fivetran Software Engineer Interview Experience — dbt Labs Team, Stumped by a SQL Engine Disk-Write Question

Fivetran acquired dbt Labs, and this position is under dbt Labs.

HR call, pretty standard, just collecting background - 30 min

HM call, introduced how the team is set up, standard behavioral questions - 1 hour

System design: design a simplified version of WhatsApp. I felt the interviewer's level was just so-so — he was still getting stuck on RDBMS vs NoSQL differences, that kind of old-school question. Mainly designed sending/receiving messages, the db schema, scaling, etc. - 1 hour

Coding — this was the most interesting round. HR said it would be algorithms and data structures, but the interviewer wanted me to implement how you'd build createDB/schema/table and the add/delete/update/query interfaces inside a SQL engine — basically the final steps of writing to disk, after SQL validation and optimization had already passed. That's what I think he was asking, anyway. Sorry to say, I genuinely didn't know this one. At first I couldn't quite figure out what he was asking, and later I roughly understood it, but then realized I just didn't know how to do it. The interviewer's attitude was nice, but testing this stuff is a bit niche. - 1 hour