官方文档Concept： checkpoint 1. A data structure that marks the checkpoint position,which is the SCN in the redo thread where instance recovery must begin.@H_301_364@Checkpointsare recorded in the control file and each data file header,and are a crucial element of recovery. 2. The writing of dirty data blocks in the database buffer cache to disk. The database writer (DBWn)process writes blocks to disk to synchronize the buffer cache with the data files.
Checkpoint Process (CKPT) The checkpoint process (CKPT)updates the control file and data file headers with checkpoint information and signals DBWnto write blocks to disk. Checkpoint information includes the checkpoint position,SCN,location in online redo log to begin recovery,and so on. As shown in Figure 15–4,CKPT does not write data blocks to data files or redo blocks to online redo log files.
