4.1 The BACKUP Block

This block is responsible for handling online backups and checkpoints. It is found in storage/ndb/src/kernel/blocks/backup/, and contains the following files:

• Backup.cpp: Defines methods for node signal handling; also provides output methods for backup status messages to user.

• BackupFormat.hpp: Defines the formats used for backup data, .CTL, and log files.

• Backup.hpp: Defines the Backup class.

• BackupInit.cpp: Actual Backup class constructor is found here.

• Backup.txt: Contains a backup signal diagram (text format). Somewhat dated (from 2003), but still potentially useful for understanding the sequence of events that is followed during backups.

• FsBuffer.hpp: Defines the FsBuffer class, which implements the circular data buffer that is used (together with the NDB file system) for reading and writing backup data and logs.

• read.cpp: Contains some utility functions for reading log and checkpoint files to STDOUT.

QBACKUP is a subtype of this block, used for query and recovery threads, added in NDB 8.0.23.