MySQL 8.4 Release Notes
下表显示了所有与 NDBCLUSTER 存储引擎相关的性能模式表。The following table shows all Performance Schema tables relating
to the NDBCLUSTER storage engine.
表 29.3 性能模式 NDB 表Table 29.3 Performance Schema NDB Tables
| 表名Table Name | 说明Description |
|---|---|
ndb_sync_excluded_objectsndb_sync_excluded_objects |
无法同步的 NDB 对象NDB objects which cannot be synchronized |
ndb_sync_pending_objectsndb_sync_pending_objects |
等待同步的 NDB 对象NDB objects waiting for synchronization |
NDB 中的自动同步尝试自动检测并同步 NDB 集群内部字典与 MySQL 服务器数据字典之间的所有元数据不匹配。默认情况下，这会在后台以 ndb_metadata_check_interval 系统变量确定的定期间隔执行，除非使用 ndb_metadata_check 禁用或通过设置 ndb_metadata_sync 覆盖。Automatic synchronization in NDB
attempts to detect and synchronize automatically all mismatches
in metadata between the NDB Cluster's internal dictionary
and the MySQL Server's datadictionary. This is done by
default in the background at regular intervals as determined by
the ndb_metadata_check_interval
system variable, unless disabled using
ndb_metadata_check or
overridden by setting
ndb_metadata_sync.
作为 NDB 集群中 SQL 节点的 MySQL 服务器，在这两个性能模式表中公开了有关自动同步当前状态的信息：Information about the current state of automatic synchronization is exposed by a MySQL server acting as an SQL node in an NDB Cluster in these two Performance Schema tables:
ndb_sync_pending_objects：显示在NDB数据库对象中发现的NDB字典与 MySQL 数据字典之间不匹配的信息。当尝试同步这些对象时，NDB会将对象从等待同步的队列中以及从此表中移除，并尝试调和不匹配。如果由于临时错误导致对象的同步失败，它将在下一次NDB执行不匹配检测时被重新拾取并重新添加到队列（以及此表）；如果尝试因永久错误失败，该对象将被添加到ndb_sync_excluded_objects表中。ndb_sync_pending_objects: Displays information aboutNDBdatabase objects for which mismatches have been detected between theNDBdictionary and the MySQL data dictionary. When attempting to synchronize such objects,NDBremoves the object from the queue awaiting synchronization, and from this table, and tries to reconcile the mismatch. If synchronization of the object fails due to a temporary error, it is picked up and added back to the queue (and to this table) the next timeNDBperforms mismatch detection; if the attempts fails due a permanent error, the object is added to thendb_sync_excluded_objectstable.ndb_sync_excluded_objects：显示由于无法通过手动干预解决的不匹配导致的永久错误而自动同步失败的NDB数据库对象的信息；这些对象被列入阻止名单，在进行手动处理之前不会重新考虑用于不匹配检测。ndb_sync_excluded_objects: Shows information aboutNDBdatabase objects for which automatic synchronization has failed due to permanent errors resulting from mismatches which cannot be reconciled without manual intervention; these objects are blocklisted and not considered again for mismatch detection until this has been done.
ndb_sync_pending_objects 和 ndb_sync_excluded_objects 表仅在 MySQL 启用了 NDBCLUSTER 存储引擎支持时才存在。The ndb_sync_pending_objects and
ndb_sync_excluded_objects tables
are present only if MySQL has support enabled for the
NDBCLUSTER storage engine.
这些表将在以下两个部分中进行更详细的描述。These tables are described in more detail in the following two sections.