DatabasesBackend
Write-Ahead Log
Also written as WAL, Transaction Log, Redo Log
A database's practice of recording what it is about to do before doing it, so an interrupted write can be recovered after a crash.
Think of it like
Writing the cheque stub before the cheque, so the record survives even if the payment is interrupted.
Junior or senior?
Underpins database recovery, replication and change data capture. Its presence suggests someone who has operated databases, not only queried them.
Ask them
“What actually happens to an in-flight transaction when a database server loses power?”