This block provides data distribution management services for
distribution information about each table, table partition, and
fragment replica of each partition. It is also responsible for
handling of local and global checkpoints.
DBDIH also manages node and system restarts.
This block is implemented in the following files, all found in
Dbdih.hpp: This file contains the definition of the
Dbdihclass, as well as the
FileRecordPtrtype, which is used to keep storage information about a fragment and its fragment replicas. If a fragment has more than one backup fragment replica, then a list of the additional ones is attached to this record. This record also stores the status of the fragment, and is 64-byte aligned.
DbdihMain.cpp: Contains definitions of
printSysfile/printSysfile.cpp: Older version of the
printSysfile.cppin the main
Dbdihdata and records; also contains the class destructor.
LCP.txt: Contains developer notes about the exchange of messages between
LQHthat takes place during a local checkpoint.
printSysfile.cpp: This file contains the source code for the ndb_print_sys_file utility program.
Sysfile.hpp: Contains the definition of the
Sysfilestructure; in other words, the format of an
NDBsystem file. See Chapter 1, NDB Cluster File Systems, for more information about
This block often makes use of
BACKUP blocks on the data
nodes to accomplish distributed tasks, such as global
checkpoints and system restarts.
This block is implemented as the
whose definition may be found in the file