Oracle 视图 ALL_PART_HISTOGRAMS 官方解释，作用，如何使用详细说明
本站中文解释
ALL_PART_HISTOGRAMS视图用于检索表和索引分区上的直方图信息，它包含了一系列帮助Optimizer 做优化工作的信息，ALL_PART_HISTOGRAMS视图是由DBMS_STATS包中的PART_HISTOGRAM_BY_PART_NAME函数维护的。
使用方法如下：
1.查看系统中所有直方图的信息：
SELECT * FROM ALL_PART_HISTOGRAMS;
2.查询指定表的所有直方图信息：
SELECT * FROM ALL_PART_HISTOGRAMS WHERE TABLE_NAME = ‘TABLE_NAME’;
3.查询指定表指定索引的直方图信息：
SELECT * FROM ALL_PART_HISTOGRAMS WHERE TABLE_NAME = ‘TABLE_NAME’ AND INDEX_NAME = ‘INDEX_NAME’;
官方英文解释
ALL_PART_HISTOGRAMS displays the histogram data (endpoints per histogram) for the histograms on the table partitions accessible to the current user.
Related Views
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DBA_PART_HISTOGRAMSdisplays the histogram data for the histograms on all table partitions in the database. -
USER_PART_HISTOGRAMSdisplays the histogram data for the histograms on the table partitions owned by the current user. This view does not display theOWNERcolumn.
Note:
These views are populated only if you collect statistics on the index using the DBMS_STATS package.
| Column | Datatype | NULL | Description |
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Owner of the table |
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Name of the table |
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Name of the table partition |
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Name of the column |
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Bucket number of the histogram |
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Normalized endpoint values for the bucket |
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Actual (not normalized) string value of the endpoint for the bucket |
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Endpoint actual value in raw format |
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Frequency of the endpoint (applies only to hybrid histograms, and is set to 0 for other histogram types) |
See Also:
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“DBA_PART_HISTOGRAMS”
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“USER_PART_HISTOGRAMS”
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Oracle Database PL/SQL
Packages and Types Reference for more information about the DBMS_STATS package
