Storing large, static data set

I am making a game which has map data stored as tiles. These tiles will not be changed more than once a release, as the data that generates them is versioned, so they are as static as the server code.

Since they are static, I thought about using a SQLite database in ram memory to store them. However, with the number of tiles in the game (could get a map up to 10,000x10,000), it could easily end up taking gigabytes of ram to store if it was kept in memory (estimated at 15gb with a 10,000x10,000 map).

I also considered creating a sqlite db and just versioning that along with the rest of the code. But I am worried about concurrent reads.

However, I feel like using a postgres database is overkill for this purpose, since the data won't change.

What would be the accepted way of dealing with a data issue like this?