Query optimization with zone map selectivity modeling

According to one embodiment of the present invention, a system for processes a query for accessing data within one or more database objects stores an element of a database object among a plurality of different storage regions. Each storage region is associated with first and second range values indicating a value range for element values within that storage region. The system examines the first and second range values for the storage regions of each database object element and determines an effectiveness value representing a degree of overlap between the storage regions of that database object element. The system determines a selectivity model for the storage regions for each database object utilizing the effectiveness value, determines a query plan based on the selectivity model, and executes the query plan. Embodiments of the present invention further include a method and computer program product for processing a query in substantially the same manners.