Glossary
Write-ahead log (WAL)
SQLite's journaling mode in which committed changes are appended to a separate -wal file before being copied into the main database at a checkpoint.
In write-ahead-log mode, SQLite leaves the database file untouched during a transaction and appends the changed pages to a companion file named <database>-wal. A transaction is committed once its commit record is in the WAL; readers check the WAL first, then the database (sqlite.org).
For Windows Timeline this means ActivitiesCache.db-wal often holds the most recent activity and the latest version of updated rows. Parsing the database without it produces a timeline that stops early. See why ActivitiesCache.db-wal matters.