This parameter specifies the number of filled on-line redo log blocks necessary to trigger a checkpoint. A checkpoint will always occur when there is an on-line redo log switch. It is usually not necessary to have Oracle perform checkpoints between log switches, though in some cases it may be desirable.
If the value specified for this parameter exceeds the overall size of the online redo log files, a checkpoint will only occur for a redo log file switch. For SAP systems, the value is set to 3000000000.