20.26.2 The INFORMATION_SCHEMA ndb_transid_mysql_connection_map Table

The ndb_transid_mysql_connection_map table provides a mapping between NDB transactions, NDB transaction coordinators, and MySQL Servers attached to a MySQL Cluster as API nodes. This information is used when populating the server_operations and server_transactions tables of the ndbinfo MySQL Cluster information database.

INFORMATION_SCHEMA NameSHOW NameRemarks
mysql_connection_id MySQL Server connection ID
node_id Transaction coordinator node ID
ndb_transid NDB transaction ID

The mysql_connection_id is the same as the connection or session ID shown in the output of SHOW PROCESSLIST.

There are no SHOW statements associated with this table.

This is a nonstandard table, added in MySQL Cluster NDB 7.1.17. It is implemented as an INFORMATION_SCHEMA plugin; you can verify that it is supported by checking the output of SHOW PLUGINS. If ndb_transid_mysql_connection_map support is enabled, the output from this statement includes a plugin having this name, of type INFORMATION SCHEMA, and having status ACTIVE, as shown here (using emphasized text):

mysql> SHOW PLUGINS;
+----------------------------------+--------+--------------------+---------+---------+
| Name                             | Status | Type               | Library | License |
+----------------------------------+--------+--------------------+---------+---------+
| binlog                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| CSV                              | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| MEMORY                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| MRG_MYISAM                       | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| MyISAM                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| PERFORMANCE_SCHEMA               | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| BLACKHOLE                        | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| ARCHIVE                          | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| ndbcluster                       | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| ndbinfo                          | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| ndb_transid_mysql_connection_map | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| InnoDB                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| INNODB_TRX                       | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_LOCKS                     | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_LOCK_WAITS                | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP                       | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP_RESET                 | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMPMEM                    | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMPMEM_RESET              | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| partition                        | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
+----------------------------------+--------+--------------------+---------+---------+

The plugin is enabled by default. You can disable it (or force the server not to run unless the plugin starts) by starting the server with the --ndb-transid-mysql-connection-map option. If the plugin is disabled, the status is shown by SHOW PLUGINS as DISABLED. The plugin cannot be enabled or disabled at runtime.

Although the names of this table and its columns are displayed using lowercase, you can use uppercase or lowercase when referring to them in SQL statements.

For this table to be created, the MySQL Server must be a binary that wass supplied with the MySQL Cluster distribution, or one that was built from the MySQL Cluster sources with NDB storage engine support enabled. It is not available in the standard MySQL 5.1 Server.