Oracle教程 2023-02-24

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

Oracle 视图DBA_HIST_IM_SEG_STAT用于显示在收集分段状态历史信息时收集的信息，其包括按片和分段收集的状态值。

Oracle视图DBA_HIST_IM_SEG_STAT包含了

1. 对象分段实例ID：为每个对象段实例分配唯一实例ID，以便在其他历史视图中引用。

2. 关联ID：为每个对象段实例分配一个唯一关联ID，并在所有相关的存量收集视图中使用，以将其与另一个对象段或一组对象段关联起来。

3. 段ID：该列包含分段的唯一ID。

4. 时间戳：该列指定行的最近更新时间。

5. 跟踪类型和状态实体ID：该列包含收集的状态信息的类型和段ID跟踪实体。

使用方法：

1. 首先，您可以使用视图DBA_HIST_IM_SEG_STAT查询收集状态信息所属的对象段或对象段实例：
SELECT * FROM dba_hist_im_seg_stat WHERE segid = &segid;

2. 其次，您可以查询与特定关联ID相关的所有收集状态信息：
SELECT * FROM dba_hist_im_seg_stat WHERE relate_id = &relate_id;

3. 你还可以使用DBA_HIST_IM_SEG_STAT视图来检索特定时间段内收集的状态值：
SELECT * FROM dba_hist_im_seg_stat
WHERE sample_time BETWEEN &start_time
AND &end_time;

DBA_HIST_IM_SEG_STAT displays information about historical in-memory segment statistics.

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
`TS#`	`NUMBER`	`NOT NULL`	Tablespace number
`OBJ#`	`NUMBER`	`NOT NULL`	Dictionary object number
`DATAOBJ#`	`NUMBER`	`NOT NULL`	Data object number
`MEMBYTES`	`NUMBER`		Size of in-memory version of the segment in bytes
`SCANS`	`NUMBER`		Count of segment statistics
`SCANS_DELTA`	`NUMBER`		Delta values for in-memory scans
`DB_BLOCK_CHANGES`	`NUMBER`		The total number of changes that were part of an update or delete operation that were made to segment blocks
`DB_BLOCK_CHANGES_DELTA`	`NUMBER`		Delta value for database block changes
`POPULATE_CUS`	`NUMBER`		Count of compression units (CUs) populated per segment
`POPULATE_CUS_DELTA`	`NUMBER`		Delta value for compression unit (CU) populate operations
`REPOPULATE_CUS`	`NUMBER`		Count of CUs repopulated per segment
`REPOPULATE_CUS_DELTA`	`NUMBER`		Delta value for compression unit (CU) repopulate operations
`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

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