Oracle教程 2023-04-05

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

本站中文解释

DBA_ZONEMAP_AUTO_FINDINGS视图显示Zone Map自动发现器的查找结果。Zone map auto finder检查ORACLE表块，并使用这些表块的信息建立索引的Zone Map。Zone Maps可以确定什么索引使用在哪些表块上。

Zone Map自动发现操作执行以下步骤:
1. 收集表的块级统计信息。
2. 运行索引分析器(Index Analyzer)，检查表块中存储的值，用于确定是否存在可能创建索引的统计信息。
3. 如果确定存在索引统计信息，则创建相应的Zone Map。

这个视图可以用于分析ORACLE表中存储的Zone Maps，以确定其是否有有效的索引，以及索引如何被使用。用途是检查ORACLE表中索引的使用情况，以及分析ORACLE索引的有效性。

官方英文解释

DBA_ZONEMAP_AUTO_FINDINGS provides information about automatic zone map findings.

Column	Datatype	NULL	Description
`TASK_ID`	`NUMBER`	`NOT NULL`	Zone map task identifier
`MSG_ID`	`NUMBER`	`NOT NULL`	Zone map message identifier
`EXEC_NAME`	`VARCHAR2(128)`		Zone map execution name
`MESSAGE`	`VARCHAR2(4000)`		Execution message text
`TIME_STAMP`	`TIMESTAMP(9)`		Finding timestamp
`OBJECT_NAME`	`VARCHAR2(128)`	`NOT NULL`	Name of the object for which the finding was observed, typically a table name or a zone map name
`FINDING_REASON`	`VARCHAR2(9)`		Finding reason code
`FINDING_TYPE`	`VARCHAR2(9)`		Finding type. Possible values: `BLACKLIST`: The table is no longer a candidate for automatic zone maps `ERROR`: An error occurred `EVICT`: The table does not meet automatic zone map creation criteria `OTHER` Refer to the `MESSAGE` column for additional information about the reasoning behind the finding type.

Automatic zone map findings contain information that the database learned when performing automatic zone map executions. The database uses these findings to optimize subsequent automatic zone maps executions, which saves on execution time and resources.

The TASK_ID, MSG_ID, and EXEC_NAME columns in this view correspond to the same columns in the DBA_ZONEMAP_AUTO_ACTIONS view. This allows you to correlate the findings in DBA_ZONEMAP_AUTO_FINDINGS with their corresponding actions in DBA_ZONEMAP_AUTO_ACTIONS.

Note:

This view is available starting with Oracle Database 21c.

本站中文解释

官方英文解释

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