EFFICIENT DATA RETRIEVAL BASED ON AGGREGATE CHARACTERISTICS OF COMPOSITE TABLES

摘要

Techniques related to efficient data retrieval based on aggregate characteristics of composite tables are provided. A join zone map includes entries that describe data from a join relationship between a first key column of a first table and a second key column of a second table. The first table includes a dimension column. Each entry of the join zone map corresponds to a respective zone. Each zone includes contiguous data blocks that correspond to one or more second key column values. Each entry also includes a respective dimension value range of one or more dimension column values. Each dimension value range includes a respective maximum dimension value and a respective minimum dimension value. Furthermore, each entry includes a respective anti-join attribute value that indicates whether any of the one or more second key column values in a particular zone are non-null and fail to match any first key column values.