Patent ID: 7319997

Claim:
A method of performing a database query including a join on an equality condition between one or more columns in a first table and one or more columns in a second table, each of the first table and the second table including zero or more rows, the method including: defining two or more first-table partitions, where each row in the first table appears in exactly one first-table partition; defining two or more second-table partitions, each second-table partition corresponding to a first-table partition, and where each row in the second table appears in exactly one second-table partition; where defining the two or more first-table partitions and the two or more second-table partitions includes: acquiring first-table-demographic data for the one or more columns in the first table, the demographic data including zero or more first-table-column values; acquiring second-table-demographic data for the one or more columns in the second table, the demographic data including zero or more second-table-column values; creating a qualifying set by joining the first table demographic data and the second table demographic data on the equality condition; partitioning the first table into the two or more first-table partitions, using the qualifying set; and partitioning the second table into the two or more second-table partitions, using the qualifying set; and for one or more corresponding first-table partitions and second-table partitions: performing the join on the first-table partition and the second-table partition; and storing the result; and merging the results.