Oracle教程 2023-02-24

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

Oracle视图V$SGA_TARGET_ADVICE用于检测并建议当前内存参数设置是否正确，其中包括SGA和PGA中推荐的大小，以及各组件之间的比列关系。可以通过查询该视图来确定当前内存配置是否合理，以及建议的值，以及用以改善的参数值。

使用方法:

1. 执行如下SQL语句，以获取SGA和PGA的推荐值：

select * from v$sga_target_advice;

2. 查询该视图中的其他字段，以了解SGA的各组件的比列关系：

select * from v$sga_target_advice where name !=‘total_sga_target_free‘;

3. 根据上述查询结果，将相关参数设置到临时区或归档区：

alter session set sga_target=查询得到的推荐值;

V$SGA_TARGET_ADVICE displays information about the SGA_TARGET initialization parameter.

Column	Datatype	Description
`SGA_SIZE`	`NUMBER`	Size of the SGA
`SGA_SIZE_FACTOR`	`NUMBER`	Ratio between the SGA_SIZE and the current size of the SGA
`ESTD_DB_TIME`	`NUMBER`	Estimated DB_TIME for this SGA_SIZE
`ESTD_DB_TIME_FACTOR`	`NUMBER`	Ratio between ESTD_DB_TIME and DB_TIME for the current size of the SGA
`ESTD_PHYSICAL_READS`	`NUMBER`	Estimated number of physical reads
`ESTD_BUFFER_CACHE_SIZE`	`NUMBER`	Estimated size of the buffer cache
`ESTD_SHARED_POOL_SIZE`	`NUMBER`	Estimated size of the shared pool
`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