性能模式 threads 表中显示了 ndbcluster 插件线程，如下查询所示

mysql> SELECT name, type, thread_id, thread_os_id
    -> FROM performance_schema.threads
    -> WHERE name LIKE '%ndbcluster%'\G
+----------------------------------+------------+-----------+--------------+
| name                             | type       | thread_id | thread_os_id |
+----------------------------------+------------+-----------+--------------+
| thread/ndbcluster/ndb_binlog     | BACKGROUND |        30 |        11980 |
| thread/ndbcluster/ndb_index_stat | BACKGROUND |        31 |        11981 |
| thread/ndbcluster/ndb_metadata   | BACKGROUND |        32 |        11982 |
+----------------------------------+------------+-----------+--------------+

threads 表显示了此处列出的所有三个线程

这些线程也按名称显示在 setup_threads 表中。

threads 和 setup_threads 表的 name 列中显示的线程名称使用 prefix/plugin_name/thread_name 格式。 prefix 是由 performance_schema 引擎确定的对象类型，对于插件线程为 thread（请参阅 线程检测元素）。 plugin_name 为 ndbcluster。 thread_name 是线程的独立名称（ndb_binlog、ndb_index_stat 或 ndb_metadata）。

使用 threads 或 setup_threads 表中给定线程的线程 ID 或操作系统线程 ID，可以从性能模式中获取有关插件执行和资源使用情况的大量信息。此示例展示了如何通过联接 threads 和 memory_summary_by_thread_by_event_name 表来获取 ndbcluster 插件创建的线程从 mem_root 区域分配的内存量

mysql> SELECT
    ->   t.name,
    ->   m.sum_number_of_bytes_alloc,
    ->   IF(m.sum_number_of_bytes_alloc > 0, "true", "false") AS 'Has allocated memory'
    -> FROM performance_schema.memory_summary_by_thread_by_event_name m
    -> JOIN performance_schema.threads t
    -> ON m.thread_id = t.thread_id
    -> WHERE t.name LIKE '%ndbcluster%'
    ->   AND event_name LIKE '%THD::main_mem_root%';
+----------------------------------+---------------------------+----------------------+
| name                             | sum_number_of_bytes_alloc | Has allocated memory |
+----------------------------------+---------------------------+----------------------+
| thread/ndbcluster/ndb_binlog     |                     20576 | true                 |
| thread/ndbcluster/ndb_index_stat |                         0 | false                |
| thread/ndbcluster/ndb_metadata   |                      8240 | true                 |
+----------------------------------+---------------------------+----------------------+

您可以通过查询性能模式 memory_summary_by_thread_by_event_name 表来查看用于事务批处理的内存量，如下所示

mysql> SELECT EVENT_NAME
    ->   FROM performance_schema.memory_summary_by_thread_by_event_name
    ->   WHERE THREAD_ID = PS_CURRENT_THREAD_ID()
    ->     AND EVENT_NAME LIKE 'memory/ndbcluster/%';
+-------------------------------------------+
| EVENT_NAME                                |
+-------------------------------------------+
| memory/ndbcluster/Thd_ndb::batch_mem_root |
+-------------------------------------------+
1 row in set (0.01 sec)

性能模式 setup_instruments 表中也显示了 ndbcluster 事务内存检测，如下所示

mysql> SELECT * from performance_schema.setup_instruments
    ->   WHERE NAME LIKE '%ndb%'\G
*************************** 1. row ***************************
         NAME: memory/ndbcluster/Thd_ndb::batch_mem_root
      ENABLED: YES
        TIMED: NULL
   PROPERTIES:
   VOLATILITY: 0
DOCUMENTATION: Memory used for transaction batching
1 row in set (0.01 sec)