If doing a SQLITE_CHECKPOINT_RESTART, the docs [1] say that the operation *ensures* the next writer will truncate the log:
"This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition that after checkpointing the log file it blocks (calls the busy-handler callback) until all readers are reading from the database file only. This ensures that the next writer will restart the log file from the beginning." This conflicts with [2]: "Whenever a write operation occurs, the writer checks how much progress the checkpointer has made, and if the entire WAL has been transferred into the database and synced and if no readers are making use of the WAL, then the writer will rewind the WAL back to the beginning and start putting new transactions at the beginning of the WAL. This mechanism prevents a WAL file from growing without bound." So if a reader begins a transaction before the next writer, then the log file will not be restarted? [I assume this is why SQLITE_CHECKPOINT_TRUNCATE was added?] [1] https://www.sqlite.org/c3ref/wal_checkpoint_v2.html [2] https://www.sqlite.org/wal.html -- Patrick Donnelly
