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公开(公告)号:US08392406B1
公开(公告)日:2013-03-05
申请号:US12190885
申请日:2008-08-13
申请人: Fatih Emekci , Sunil P. Chakkappen , Uri Shaft
发明人: Fatih Emekci , Sunil P. Chakkappen , Uri Shaft
IPC分类号: G06F7/00
CPC分类号: G06F17/18 , G06F17/30501
摘要: A table-level histogram is maintained incrementally without requiring rescanning of the entire table when new data values are added to the table. A table has multiple partitions of data values. A histogram for data values of the partitions is generated. When a new partition of data values is added to the table, a histogram for only the new partition is generated. To generate a histogram for the entire table, the histograms for the previously generated and newly added partitions are used without needing to refer to the underlying data. A similar approach is applicable when modifying data values in a partition.
摘要翻译: 当将新的数据值添加到表中时,表级别的直方图将逐步维护,而不需要对整个表进行重新扫描。 一个表有多个分区的数据值。 生成分区数据值的直方图。 当新的分区数据值被添加到表中时,仅生成新分区的直方图。 为了生成整个表的直方图,使用先前生成的和新添加的分区的直方图,而不需要参考底层数据。 修改分区中的数据值时,也可以使用类似的方法。