I had to move a MongoDB to PG database on my new job (old contractor created MVP, I was hired to be the "CTO" of this new startup) and I had some problems at fi

I had to move a MongoDB to PG database on my new job (old contractor created MVP, I was hired to be the "CTO" of this new startup) and I had some problems at first, but after I created the related models and added indexes, everything worked fine. As someone said, indexes are the best to do lookups. Remember your DB engine do lookups internally even if you are not aware (joins, for example), so add indexes to join fields. Another thing that worked me for me (and I dont know if it's your case), was to add trigram text indexes, which make it faster to do a full text search. Remember, anyway, that adding a index makes search faster, but insert slower, so be careful if you are inserting a lot of data.