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Optimizing Database Table Scans in the Presence of Ordered Data

机译:在有序数据的存在下优化数据库表扫描

摘要

Optimizing database table scans in presence of SMDO records is provided. An SMDO record corresponding to a most recent span of rows for a column associated with a query predicate is read. It is determined whether a condition for excluding a span of rows is true for the SMDO record based on a type of the query predicate. In response to determining that a condition for excluding a span of rows is not true for the SMDO record, the most recent span of rows is added to a list of spans of rows to scan. It is determined whether a condition for excluding all preceding spans of rows is true for the SMDO record based on the type of the query predicate. In response to determining that a condition for excluding all preceding spans of rows is true for the SMDO record, reading the set of SMDO records is stopped.
机译:提供了在SMDO记录的存在下优化数据库表扫描。读取对应于与查询谓词相关联的列的最新行的SMDO记录。确定基于查询谓词的类型的SMDO记录是针对SWDO记录排除的条件。响应于确定SMDO记录的排除行为的条件不为真,将最新的行跨度添加到要扫描的行的跨度列表中。基于查询谓词的类型,确定用于排除所有前一行跨度的条件是否为TRUE。响应于确定SMDO记录的排除所有前一行跨度的条件都是如此,读取SMDO记录集被停止。

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