At work, I was told to use add sort to a mongo query & I ended up doing just that but something I never realized was performance aspect of the query.

While locally, the modified query will run just fine. It’s the production performance you should always be concerned about.

So I was pointed to explain function that will spit out plans that will let you optimize the query.

From what I have gathered, we should avoid queries that have to scan all documents & it will show up as COLLSCAN in the explain function results. That means you would want to create an index for every parameter (or combination of parameters) you’re going to use in your mongo queries.

This blog post explains the explain function very well: https://www.percona.com/blog/2018/09/06/mongodb-investigate-queries-with-explain-index-usage-part-2/