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6.6. NDB Internals Glossary

This section contains terms and abbreviations that are found in or useful to understanding the NDB source code.

  • ACC.  ACCelerator or ACCess manager. Handles hash indexes of primary keys, providing fast access to records. See Section 6.4.3, “The DBACC Block”.

  • API node.  In NDB terms, this is any application that accesses cluster data using the NDB API, including mysqld when functioning as an API node. (MySQL servers acting in this capacity are also referred to as “SQL nodes”). Often abbreviated to “API”.

  • CMVMI.  Stands for Cluster Manager Virtual Machine Interface. An NDB kernel handling nonsignal requests to the operating system, as well as configuration management, interaction with the cluster management server, and interaction between various kernel blocks and the NDB virtual machine. See Section 6.4.2, “The CMVMI Block”, for more information.

  • CNTR.  Stands for restart CoordiNaToR. See Section 6.4.12, “The NDBCNTR Block”, for more information.

  • DBTC.  The transaction coordinator (also sometimes written simply as TC). See Section 6.4.7, “The DBTC Block”, for more information.

  • DICT.  The NDB data DICTionary kernel block. Also DBDICT. See Section 6.4.4, “The DBDICT Block”.

  • DIH.  DIstribution Handler. An NDB kernel block. See Section 6.4.5, “The DBDIH Block”.

  • LGMAN.  The Log Group MANager NDB kernel block, used for MySQL Cluster Disk Data tables. See Section 6.4.11, “The LGMAN Block”.

  • LQH.  Local Query Handler. NDB kernel block, discussed in Section 6.4.6, “DBLQH Block”.

  • MGM.  ManaGeMent node (or management server). Implemented as the ndb_mgmd server daemon. Responsible for passing cluster configuration information to data nodes and performing functions such as starting and stopping nodes. Accessed by the user by means of the cluster management client (ndb_mgm). A discussion of management nodes can be found in ndb_mgmd.

  • QMGR.  The cluster management block in the NDB kernel. It responsibilities include monitoring heartbeats from data and API nodes. See Section 6.4.15, “The QMGR Block”, for more information.

  • RBR.  Row-Based Replication. MySQL Cluster Replication is row-based replication. See MySQL Cluster Replication.

  • STTOR.  STart Or Restart

  • SUMA.  The cluster SUbscription MAnager. See Section 6.4.17, “The SUMA Block”.

  • TC

    TC.  Transaction Coordinator. See Section 6.4.7, “The DBTC Block”.

  • TRIX.  Stands for TRansactions and IndeXes, which are managed by the NDB kernel block having this name. See Section 6.4.19, “The TRIX Block”.

  • TSMAN.  Table space manager. Handles tablespaces for MySQL Cluster Disk Data. See Section 6.4.18, “The TSMAN Block”, for more information.

  • TUP.  TUPle. Unit of data storage. Also used (along with DBTUP) to refer to the NDB kernel's tuple management block, which is discussed in Section 6.4.8, “The DBTUP Block”.