Checkpoints can be performed online or offline.

An online checkpoint, which is the default, can be performed while users are connected to the database. A full online checkpoint stalls until any transactions running against the database are committed. Any new transactions started during the stall phase of the online checkpoint cannot run until the stall phase is completed.

Incremental online checkpoints can proceed while DML transactions are active.

An offline checkpoint can be performed when no one is using the database.