checkpoint

The DBMS checkpoint is a procedure of compressing the transaction log file by transferring the old transaction to permanent storage. It helps in system recovery when the failure occurs. The procedure of system recovery includes reading of log file in reverse order and maintaining redo and undo lists. A checkpoint writes the current in-memory modified pages (known as dirty pages) and transaction log information from memory to disk, and also records the information in the transaction log. The Database Engine supports several types of checkpoints: automatic, indirect, manual, and internal. The checkpoint is used to declare a point before which the DBMS was in the consistent state, and all transactions were committed. During transaction execution, such checkpoints are traced. After execution, transaction log files will be created.