Checkpoint is a process that writes current in-memory dirty pages (modified pages) and transaction log records to physical disk. In SQL Server checkpoints are used to reduce the time required for recovery in the event of system failure. Checkpoint is regularly issued for each database. The following set of operations starts when checkpoint occurs:
- Log records from log buffer (including the last log record) are written to the disk.
- All dirty data file pages (pages that have been modified since the last checkpoint or since they were read from disk) are written into the data file from the buffer cache.
- Checkpoint LSN is recorded in the database boot page.
