That is exactly it. Some SQL databases (CockroachDB and Postgres come to mind) can have the option of having O(1) JSON lookup. It just has to implement the corr

That is exactly it. Some SQL databases (CockroachDB and Postgres come to mind) can have the option of having O(1) JSON lookup. It just has to implement the correct algorithm, and index the data the correct way. It is not about the database type. It is about the underlying algorithms and data structures.