alt Hacker NewsProduction grade multi tenant databases want to *solely* run on RAM.
> why would you not want to index?
Because if you don't need an index it wastes RAM, as you've learned. Maintaining indices also has a cost. Index only what you need.
In the sense of the blog post: A senior with decent DB experience would have told you. ;)
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Everything "wants to" run solely in RAM, but we don't have infinite RAM, so a "production grade" database should also be able to fetch data from disk unless this is an explicit tradeoff. MariaDB and PostgreSQL do not require all indices to be stored in RAM. Obviously they can be accessed more quickly if they are in RAM but they are designed under the assumption they will often be stored on disk. It sounds like MongoDB is not, and given the reputation of MongoDB, this is as likely to be incompetence as it is to be a willing tradeoff.
You mean NoSQL which is slightly different and nuanced, in a shop that was mostly SQL with the exception of me, the one Junior developer using MongoDB and Elastic, mind you, we got a lot of things done and I learned a lot more about Mongo than I would like.
In all fairness this was my first job a few years ago as a developer, I deep dove MongoDB but I was also one of the only devs using it at this place.
My previous experience with MongoDB had been in college and more limited.