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

本站中文解释

V$MEMORY_TARGET_ADVICE视图显示内存管理的建议参数设置,其中有两个列:

COMPONENT:实例参数组件名称
RECOMMENDATION:根据当前数据库调用推荐的内存参数值。

使用V$MEMORY_TARGET_ADVICE视图,用户可以查看实例参数(如sga_target和pga_aggreate_target)的建议值,以调整当前系统的内存管理。此外,用户可以根据此视图查看正在运行参数设置是否符合实际情况,如果不合适,可以根据它的建议值重新调整参数。

官方英文解释

V$MEMORY_TARGET_ADVICE provides information about how the MEMORY_TARGET parameter should be sized based on current sizing and satisfaction metrics.

Column Datatype Description

MEMORY_SIZE

NUMBER

If the MEMORY_SIZE_FACTOR column has a value of 1, then this column shows the current size of memory, as set by the MEMORY_TARGET initialization parameter.

If the value of the MEMORY_SIZE_FACTOR column is less than or greater than 1, then this column shows a proposed memory size.

MEMORY_SIZE_FACTOR

NUMBER

A multiplier for the current memory size. Possible values are 0.25, 0.5, 0.75, 1, 1.5, 1.75, and 2. This multiplier times the current memory size equals the value of the MEMORY_SIZE column.

ESTD_DB_TIME

NUMBER

For current memory size (MEMORY_SIZE_FACTOR = 1), the amount of database time required to complete the current workload. For a proposed memory size, the estimated amount of database time that would be required if the MEMORY_TARGET parameter were changed to the proposed size.

ESTD_DB_TIME_FACTOR

NUMBER

For a proposed memory size, ratio of estimated database time to current database time

VERSION

NUMBER

Version number of this recommendation (this snapshot of the V$MEMORY_TARGET_ADVICE view)

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

Table 9-2 shows how the information provided in V$MEMORY_TARGET_ADVICE could be used to improve performance. The data indicates that if current memory size is 380M, and you were to increase it to 760M (2x), the current workload would take 80525 units of DBtime as opposed to 115475 units of DBtime, which is a significant improvement in performance.

Table 9-2 Example of Using V$MEMORY_TARGET_ADVICE

MEMORY_SIZE MEMORY_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR VERSION

380

1

115475

1

3

95

.25

200500

1.7

3

190

.5

125600

1.1

3

760

2

80525

0.7

3

See Also:

“MEMORY_TARGET”


数据运维技术 » Oracle 视图 V$MEMORY_TARGET_ADVICE 官方解释,作用,如何使用详细说明