About SQLite : running :memory:

Good to know!

Running Repo.start_link(database: ":memory:", default_chunk_size: 100) will use the default pool size where each database connection in the pool will open its own in memory database.

If you want to use an in memory database, you'll need to crank the pool size down to 1. I don't recommend doing that right now for application code because you'll have to migrate / load a structure everytime the connection is opened.

When you use any other value for the database name, it's just using that value as the path to the database from the application directory.
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