Oracle教程 2023-04-05

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

该视图DR$STATISTICS_LEVEL用于查看Oracle中的当前统计级别。当希望了解当前的统计级别是什么时，可以查看该视图，该视图的列STATS_LEVEL中对应的参数值就是当前的统计信息级别。

使用方法：

1.登录Oracle数据库实例，使用始终表空间的用户进行查询。

2.通过以下Oracle命令查看V$STATISTICS_LEVEL视图：

SQL> SELECT STATS_LEVEL FROM V$STATISTICS_LEVEL;

3.视图V$STATISTICS_LEVEL中只有一列，STATS_LEVEL，代表当前数据库实例的统计级别，若STATS_LEVEL可以等于‘ALL ESTIMATES’，‘SUMMARY’或‘TYPICAL’，则对应级别依次为低、中、高。

V$STATISTICS_LEVEL displays the status of the statistics/advisories controlled by STATISTICS_LEVEL.

Column	Datatype	Description
`STATISTICS_NAME`	`VARCHAR2(64)`	Name of the statistic/advisory
`DESCRIPTION`	`VARCHAR2(4000)`	Description of the statistic/advisory
`SESSION_STATUS`	`VARCHAR2(8)`	Status of the statistic/advisory for the session: `ENABLED` `DISABLED`
`SYSTEM_STATUS`	`VARCHAR2(8)`	System-wide status of the statistic/advisory: `ENABLED` `DISABLED`
`ACTIVATION_LEVEL`	`VARCHAR2(7)`	Indicates the level of `STATISTICS_LEVEL` that enables the statistic/advisory: `BASIC` `TYPICAL` `ALL`
`STATISTICS_VIEW_NAME`	`VARCHAR2(64)`	If there is a single view externalizing the statistic/advisory, then this column contains the name of that view. If there is no such view, then this column is null. If there are multiple views involved, then the `DESCRIPTION` column mentions the view names.
`SESSION_SETTABLE`	`VARCHAR2(3)`	Indicates whether the statistic/advisory can be set at the session level (`YES`) or not (`NO`)
`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