SELECTIVITY ESTIMATION FOR QUERY EXECUTION PLANNING IN A DATABASE

A computer-implemented method of estimating selectivity of a query may include generating, for data stored in a database in a memory, a one-dimensional value distribution for each of a plurality of attributes of the data. A multidimensional histogram may be generated, wherein the multidimensional histogram includes the one-dimensional value distributions for the plurality of attributes of the data. The multidimensional histogram may be converted to a one-dimensional histogram by assigning each bucket of the multidimensional histogram to corresponding buckets of the one-dimensional histogram and ordering the corresponding buckets according to a space-filling curve. One or more bucket ranges of the one-dimensional histogram may be determined by mapping the query conditions on the one-dimensional histogram. The selectivity of the query may be estimated by estimating how many data values in the one or more bucket ranges will meet the query conditions.