- MySQL 5.1 Reference Manual :: 17 MySQL Cluster NDB 6.X/7.X :: 17.3 MySQL Cluster Configuration :: 17.3.4 MySQL Server Options and Variables for MySQL Cluster :: 17.3.4.4 MySQL Cluster Status Variables
-
- MySQL 5.1 Reference Manual
- Preface, Notes, Licenses
- 1 General Information
- 2 Installing and Upgrading MySQL
- 3 Tutorial
- 4 MySQL Programs
- 5 MySQL Server Administration
- 6 Backup and Recovery
- 7 Optimization
- 8 Language Structure
- 9 Internationalization and Localization
- 10 Data Types
- 11 Functions and Operators
- 12 SQL Statement Syntax
- 13 Storage Engines
- 14 High Availability and Scalability
- 15 MySQL Enterprise Monitor
- 16 Replication
- 17 MySQL Cluster NDB 6.X/7.X
- 18 Partitioning
- 19 Stored Programs and Views
- 20 INFORMATION_SCHEMA Tables
- 21 Connectors and APIs
- 22 Extending MySQL
- A MySQL 5.1 Frequently Asked Questions
- B Errors, Error Codes, and Common Problems
- C MySQL Change History
- D Restrictions and Limits
- Index
- Standard Index
- C Function Index
- Command Index
- Function Index
- INFORMATION_SCHEMA Index
- Transaction Isolation Level Index
- JOIN Types Index
- Operator Index
- Option Index
- Privileges Index
- SQL Modes Index
- Status Variable Index
- Statement/Syntax Index
- System Variable Index
This section provides detailed information about MySQL server status variables that relate to MySQL Cluster and the
NDBstorage engine. For status variables not specific to MySQL Cluster, and for general information on using status variables, see Section 5.1.6, “Server Status Variables”.-
The MySQL server can ask the
NDBCLUSTERstorage engine if it knows about a table with a given name. This is called discovery.Handler_discoverindicates the number of times that tables have been discovered via this mechanism. -
If the server is acting as a MySQL Cluster node, then the value of this variable its node ID in the cluster.
If the server is not part of a MySQL Cluster, then the value of this variable is 0.
-
If the server is part of a MySQL Cluster, the value of this variable is the host name or IP address of the Cluster management server from which it gets its configuration data.
If the server is not part of a MySQL Cluster, then the value of this variable is an empty string.
Prior to MySQL 5.1.12, this variable was named
Ndb_connected_host. -
If the server is part of a MySQL Cluster, the value of this variable is the number of the port through which it is connected to the Cluster management server from which it gets its configuration data.
If the server is not part of a MySQL Cluster, then the value of this variable is 0.
Prior to MySQL 5.1.12, this variable was named
Ndb_connected_port. -
Provides the number of round trips to the
NDBkernel made by operations. Added in MySQL Cluster NDB 6.3.6. -
If the server is part of a MySQL Cluster, the value of this variable is the number of data nodes in the cluster.
If the server is not part of a MySQL Cluster, then the value of this variable is 0.
Prior to MySQL 5.1.12, this variable was named
Ndb_number_of_storage_nodes. -
Shows the replication heartbeat interval (in seconds) on a replication slave.
This variable was added in MySQL Cluster NDB 6.3.4.
-
This counter increments with each replication heartbeat received by a replication slave since the last time that the slave was restarted or reset, or a
CHANGE MASTER TOstatement was issued.This variable was added in MySQL Cluster NDB 6.3.4.
-
This variable holds a count of the number of scans executed by
NDBCLUSTERsince the MySQL Cluster was last started whereNDBCLUSTERwas able to use partition pruning.Using this variable together with
Ndb_scan_countcan be helpful in schema design to maximize the ability of the server to prune scans to a single table partition, thereby involving only a single data node.This variable was added in MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.5.
-
This variable holds a count of the total number of scans executed by
NDBCLUSTERsince the MySQL Cluster was last started.This variable was added in MySQL Cluster NDB 6.3.25 and MySQL Cluster NDB 7.0.5.