Write all dirty pages to disk.
Syntax CHECKPOINT [duration] Key duration Time for the checkpoint to complete (seconds).
CHECKPOINT will write to disk all those data pages in the buffer cache of the current database which have been modified, but not yet written to disk.
Issuing SHUTDOWN WITH NOWAIT or directly stopping the msSqlServer service from the Windows control panel will not perform a checkpoint. When the database is restarted, this will force a rollback operation to occur for any uncompleted transactions.
"The checkpoint is not a security measure designed to prevent terrorists from transporting bombs. It is a political tactic aimed at making Palestinians suffer in order to break their wills" - Wendy Pearlman
Equivalent Oracle command:
ALTER SYSTEM FLUSH SHARED POOL