Learn in the textbookFailure Recovery
DefinitionA checkpoint (チェックポイント) is the operation of writing updates held in memory out to disk all at once, or the moment at which that operation is carried out.
ExplanationTo speed up processing, the DBMS does not write updates to disk right away but first holds them in a buffer in memory. When checkpoints are taken at regular intervals, every update up to that moment is already reflected on disk. After a failure that stops the system but leaves the disk intact, recovery can start from the latest checkpoint instead of tracing the log, the record of updates written in order, all the way from the beginning.
AnalogyIt is like making a clean copy of your household account book at the end of each month: if you spot a mistake, you only need to recheck from the most recent month-end.
Memory hookCheck plus point: the point at which you have confirmed the updates are on disk.