Oracle 视图 DBA_HIST_MEM_DYNAMIC_COMP 官方解释，作用，如何使用详细说明

_ALLOC

Oracle 视图DBA_HIST_MEM_DYNAMIC_COMP_ALLOC 是存储在回收例程中收集的内存动态组件分配历史信息的表视图，该表视图用于查看给出组件分配情况，以便检查其动态特性是否超出其限制，或者检查内存 EDU 池是否已使用到极限，使应用程序拥有充足的内存资源。

使用此表，可以确定数据库的内存增长或收缩趋势，并采取合理的措施保持其合理性。此外，可以查看每个数据库实例的内存组件分配情况，以确定其动态特性是否超出其限制，或者检查内存 EDU 池是否已使用到极限。

要使用此表，您需要执行以下查询：

SELECT *
FROM DBA_HIST_MEM_DYNAMIC_COMP_ALLOC;

DBA_HIST_MEM_DYNAMIC_COMP displays historical memory component sizes.

This view contains snapshots of V$MEMORY_DYNAMIC_COMPONENTS.

Column	Datatype	NULL	Description
`SNAP_ID`	`NUMBER`	`NOT NULL`	Unique snapshot ID
`DBID`	`NUMBER`	`NOT NULL`	Database ID for the snapshot
`INSTANCE_NUMBER`	`NUMBER`	`NOT NULL`	Instance number for the snapshot
`COMPONENT`	`VARCHAR2(64)`	`NOT NULL`	Component name
`CURRENT_SIZE`	`NUMBER`		Current size of the component
`MIN_SIZE`	`NUMBER`		Minimum size of the component since instance startup
`MAX_SIZE`	`NUMBER`		Maximum size of the component since instance startup
`USER_SPECIFIED_SIZE`	`NUMBER`		Value of the user parameter for the component
`OPER_COUNT`	`NUMBER`		Number of operations since instance startup
`LAST_OPER_TYPE`	`VARCHAR2(13)`		Last completed operation for the component: `STATIC` `INITIALIZING` `DISABLED` `GROW` `SHRINK` `SHRINK_CANCEL`
`LAST_OPER_MODE`	`VARCHAR2(9)`		Mode of the last completed operation: `MANUAL` `DEFERRED` `IMMEDIATE`
`LAST_OPER_TIME`	`DATE`		Start time of the last completed operation
`GRANULE_SIZE`	`NUMBER`		Granularity of the `GROW` or `SHRINK` operation
`CON_DBID`	`NUMBER`		The database ID of the PDB for the sampled session
`CON_ID`	`NUMBER`		The ID of the container that `CON_DBID` identifies. 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