ndb_transid_mysql_connection_map 表提供了 NDB 事务、NDB 事务协调器以及作为 API 节点连接到 NDB 集群的 MySQL 服务器之间的映射。这些信息用于填充 server_operations 和 server_transactions 表，这些表属于 ndbinfo NDB 集群信息数据库。The ndb_transid_mysql_connection_map table provides a mapping between NDB transactions, NDB transaction coordinators, and MySQL Servers attached to an NDB Cluster as API nodes. This information is used when populating the server_operations and server_transactions tables of the ndbinfo NDB Cluster information database.

mysql_connection_id 与 SHOW PROCESSLIST 输出中显示的连接或会话 ID 相同。The mysql_connection_id is the same as the connection or session ID shown in the output of SHOW PROCESSLIST.

此表没有与之相关的 SHOW 语句。There are no SHOW statements associated with this table.

这是一个非标准表，特定于 NDB Cluster。它作为一个 INFORMATION_SCHEMA 插件实现；您可以通过检查 SHOW PLUGINS 的输出，来验证它是否被支持。如果 ndb_transid_mysql_connection_map 支持被启用，则该语句的输出将包含一个名称为此插件的插件，类型为 INFORMATION SCHEMA，并且状态为 ACTIVE，如下所示（使用强调文本）：This is a nonstandard table, specific to NDB Cluster. 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     |
| mysql_native_password            | ACTIVE | AUTHENTICATION     | NULL    | GPL     |
| sha256_password                  | ACTIVE | AUTHENTICATION     | NULL    | GPL     |
| caching_sha2_password            | ACTIVE | AUTHENTICATION     | NULL    | GPL     |
| sha2_cache_cleaner               | ACTIVE | AUDIT              | NULL    | GPL     |
| daemon_keyring_proxy_plugin      | ACTIVE | DAEMON             | NULL    | GPL     |
| CSV                              | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| MEMORY                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| InnoDB                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| INNODB_TRX                       | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| INNODB_CMP                       | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |

...

| INNODB_SESSION_TEMP_TABLESPACES  | ACTIVE | INFORMATION SCHEMA | NULL    | GPL     |
| MyISAM                           | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| MRG_MYISAM                       | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| PERFORMANCE_SCHEMA               | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| TempTable                        | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| ARCHIVE                          | ACTIVE | STORAGE ENGINE     | NULL    | GPL     |
| BLACKHOLE                        | 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     |
| ngram                            | ACTIVE | FTPARSER           | NULL    | GPL     |
| mysqlx_cache_cleaner             | ACTIVE | AUDIT              | NULL    | GPL     |
| mysqlx                           | ACTIVE | DAEMON             | NULL    | GPL     |
+----------------------------------+--------+--------------------+---------+---------+
47 rows in set (0.01 sec)

该插件默认启用。您可以通过使用 --ndb-transid-mysql-connection-map 选项启动服务器来禁用它（或强制服务器在插件未启动时不运行）。如果插件被禁用，其状态会通过 SHOW PLUGINS 显示为 DISABLED。该插件无法在运行时启用或禁用。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.

虽然此表及其列的名称显示为小写，但在 SQL 语句中引用它们时可以使用大写或小写。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.

要创建此表，MySQL 服务器必须是随 NDB Cluster 分发的二进制版本，或是从 NDB Cluster 源代码构建并启用了 NDB 存储引擎支持的版本。在标准的 MySQL 8.4 服务器中不可用。For this table to be created, the MySQL Server must be a binary supplied with the NDB Cluster distribution, or one built from the NDB Cluster sources with NDB storage engine support enabled. It is not available in the standard MySQL 8.4 Server.