> You have SQLite .db and .db-wal files, but no accompanying .db-shm file. Maybe your friend shared it with you, or you downloaded some data off the internet.

Honestly this sounds out of scope for normal usage of sqlite and not realistic. I had a hard time reading past this. If I read that correctly, they're saying sqlite doesn't work if one of the database files disappears from under it.

I guess if you had filesystem corruption it's possible that .db-shm disappears without notice and that's a problem. But that isn't sqlite's fault.

This, exactly. Especially since these files are basically the "this database was not cleanly closed" markers for SQLite. From SQLite's docs:

> If the last client using the database shuts down cleanly by calling sqlite3_close(), then a checkpoint is run automatically in order to transfer all information from the wal file over into the main database, and both the shm file and the wal file are unlinked.