A checkpointed main file holds 10 while committed WAL holds the change to 20. A main-only copy remains at 10; the online backup API captures 20.

SQLite is an embedded database engine

SQLite is a database engine linked into the application rather than a separate database server. Its main database file stores schema, tables, and indexes in a portable format. That makes it useful for local application state, embedded devices, and services whose write workload fits its concurrency model. The file is still governed by transactions and locking; ordinary file-copy intuition is not enough to operate it safely. ...

October 20, 2026 · 5 min · XB Field Notes