Oracle 视图 V$PX_INSTANCE_GROUP 官方解释，作用，如何使用详细说明-云搜网

_SYNC

Oracle 定义的V$PX_INSTANCE_GROUP_SYNC是一种动态视图，用于显示实例间的同步状态，它以一对对的方式展示RAC实例的状态。它的每一行是一个RAC实例组中两个实例之间的关系，可以显示这两个实例之间同步消息的状态，以及在索引上，它是否有一个活动节点，另一个是准备状态。

该视图用来查看RAC 数据库实例之间同步的配置和状态信息。可以用它来检查任何不正常的同步部件，例如停止的同步或失败的同步会话。使用该视图可以进行更加精准的性能监控，帮助企业获得更好的吞吐量、应用程序可靠性和数据完整性。

要使用V$PX_INSTANCE_GROUP_SYNC的数据，你应该登录到一个RAC实例，然后执行如下查询：
SELECT * FROM V$PX_INSTANCE_GROUP_SYNC;

V$PX_INSTANCE_GROUP provides information about the instance groups being used for parallel operations by the current session.

Column	Datatype	Description
`QC_INSTANCE_GROUP`	`VARCHAR2(64)`	The instance group being used by this session for parallel operations. This value repeats for every row returned.
`WHY`	`VARCHAR2(23)`	Where the current instance group name comes from, as follows: SERVICE – the instance group being used is from the session’s service name PARALLEL_INSTANCE_GROUP – the instance group being used is being used because the PARALLEL_INSTANCE_GROUP initialization parameter has been set. The value repeats for every row returned.
`INSTANCE_NUMBER`	`NUMBER`	Instance number of the instance providing this instance group. There will be one row for each instance in the instance group that the Query Coordinator is using.
`CON_ID`	`NUMBER`	The ID of the container to which the data pertains. Possible values include: `0`: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs. `1`: This value is used for rows containing data that pertain to only the root n: Where n is the applicable container ID for the rows containing data

Oracle 视图 V$PX_INSTANCE_GROUP 官方解释，作用，如何使用详细说明