The present disclosure relates to a computer-implemented method, computer program product, and computer system, for optimization of query processing a set of data extents on which a table is stored. Attribute value information may be maintained for each data extent. The attribute value information indicate as ranges the minimum and maximum values of an attribute of the entries stored in the respective extent. A first metric of a first data extent of the set may determine splitting the first data extent into sub-extents increases query processing efficiency. A second metric of a second data extent and a third data extent may determine merging the second data extent and the third data extent increases query processing efficiency.