Database owners can issue the checkpoint command to force all modified pages that are in memory to be written to disk.
Manual checkpoints do not truncate the log, even if the trunc log on chkpt option of sp_dboption is turned on.
As a precautionary measure in special circumstances—for example, just before a planned shutdown with nowait so that SAP ASE recovery mechanisms occur within the recovery interval. (An ordinary shutdown performs a checkpoint.)
To cause a change in database options to take effect after executing sp_dboption. (After you run sp_dboption, an informational message reminds you to run checkpoint.)
You can use checkpoint to identify one or more databases or use an all clause, which checkpoints all databases. See the Reference Manual: Commands.