Oracle教程 2023-02-24

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

V$ZONEMAP_USAGE_STATS视图是用来显示与Zone Map 有关统计信息的视图，其中包括一些常见操作，如读取数据块、写数据块、检查及更新表空间区域等等。这个视图最适合用来检查数据库空间块使用情况以及表空间区域检查和更新的比例。

使用方法：

1. 查询数据库块使用情况：

SELECT tablespace_name, SUM(reads) read_count, SUM(writes) write_count
FROM V$ZONEMAP_USAGE_STATS
GROUP BY tablespace_name;

2. 查询表空间区域更新情况：

SELECT tablespace_name, SUM(zone_map_verifies) verify_count, SUM(zone_map_updates) update_count
FROM V$ZONEMAP_USAGE_STATS
GROUP BY tablespace_name;

V$ZONEMAP_USAGE_STATS displays zone map usage statistics.

Column	Datatype	Description
`ZONEMAP`	`VARCHAR2(257)`	Name of the zone map in the form of owner.name
`PRUNING_TYPE`	`VARCHAR2(11)`	Type of data pruning performed using the zone map
`EXECUTIONS`	`NUMBER`	Number of executions, including parallel slave executions
`BASE_COUNT`	`NUMBER`	Base count accumulated over number of executions
`PRUNED_COUNT`	`NUMBER`	Pruned count accumulated over number of executions
`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

The ratio (PRUNED_COUNT / BASE_COUNT) shows the fraction of data pruned by the zone map.

分享到：