There is a significant warning about the use of WAL mode, very plain in the documentation: "Transactions involving multiple attached databases are atomic, assu

There is a significant warning about the use of WAL mode, very plain in the documentation: "Transactions involving multiple attached databases are atomic, assuming that the main database is not ":memory:" and the journal_mode is not WAL. If the main database is ":memory:" or if the journal_mode is WAL, then transactions continue to be atomic within each individual database file. But if the host computer crashes in the middle of a COMMIT where two or more database files are updated, some of those files might get the changes where others might not." https://sqlite.org/lang_attach.html https://sqlite.org/lang_attach.html Systems designed for DML against multiple database files should eschew WAL mode.