646 B
646 B
NOTES
RECOVERY
REAL WAL EXISTS, SHADOW EXISTS
Scenario: Unclean close by application process.
Action: Verify last page from both match.
REAL WAL DOESN'T EXISTS, SHADOW EXISTS
Scenario: Application closed cleanly & removed WAL.
Action: Verify last page of shadow matches database page.
REAL WAL EXISTS, SHADOW DOESN'T EXIST
Scenario: Application wrote WAL; system crashed before shadow written/sync'd.
Action: Start new generation.
REAL WAL DOESN'T EXIST, SHADOW DOESN'T EXIST
Scenario: No writes have occurred since the DB was switched to WAL mode.
Action: Nothing to recover. Wait for first WAL write.