Oracle教程 2023-03-31

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

V$PARALLEL_DEGREE_LIMIT_MTH是Oracle数据库中的一个视图，用于查看操作系统最大可用并行度限制值。通过该视图，用户可以获取Oracle服务器当前所设定的操作系统最大并行度。

该视图中包含一个名为VALUE的列，它指定操作系统中最大可限制的并行度值。该值可以使用SQL语句中的PARALLEL_MAX_SERVERS和PARALLEL_THREADS_PER_CPU参数动态调节，允许系统能够以不同的并行度来执行不同类型的拥挤的查询任务。

建议在调整操作系统最大可用并行度限制值之前，应先检查V $PARALLEL_DEGREE_LIMIT_MTH视图中的现有限制值，以确认更改是必要的。如果有必要，则可以使用代码修改这个值，以确保为整个数据库提供最大的吞吐量。

V$PARALLEL_DEGREE_LIMIT_MTH displays all available parallel degree limit resource allocation methods.

Column Datatype Description

Column	Datatype	Description
`NAME`	`VARCHAR2(40)`	Name of the parallel degree limit resource allocation method
`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

NAME

VARCHAR2(40)

Name of the parallel degree limit resource allocation method

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

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