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

本站中文解释

显示 SQL 命令行缓存内存的当前状态

Oracle视图V$RESULT_CACHE_MEMORY用于显示SQL命令行缓存内存的当前状态。它显示内存的大小，以及缓存内存已使用的大小，它还会显示内存中结果的命中率，以及每秒执行的查询数量。

Oracle视图V$RESULT_CACHE_MEMORY能够帮助用户更好的理解当前的缓存内存的状态，用户可以用它查看缓存命中率，在必要的情况下，可以扩展更多的内存。用户可以用它查看每秒执行的查询数量，用来判断缓存是否可以使用，如果查询数量不足，则有必要启用缓存。用户也可以根据可用的缓存大小采取相应的措施，来确保系统的性能。

官方英文解释

V$RESULT_CACHE_MEMORY displays all the memory blocks and their status.

Column Datatype Description

ID

NUMBER

Unique block identifier (that is, the block number)

CHUNK

NUMBER

Chunk to which the block belongs, relative to the subcache in which the memory object resides (the upper 27 bits of the ID)

OFFSET

NUMBER

Offset of the block within its chunk, relative to the subcache in which the memory object resides (the lower 5 bits of the ID)

SUBCACHE_IDFoot 1

NUMBER

Subcache ID

FREE

VARCHAR2(3)

Indicates whether the block is free (YES) or not (NO)

OBJECT_ID

NUMBER

Cache object to which the memory block belongs; NULL if the memory block is not allocated to a cache object (FREE = YES)

POSITION

NUMBER

Position of the block in the cached object; NULL if the memory block is not allocated to a cache object (FREE = YES)

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

Footnote 1 This column is available starting with Oracle Database 21c.


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