Advanced structural joins using element distribution

For accelerating a structural join operation, current techniques focus on skipping elements that do not contribute to the results. They make use of external index structures (e.g. B+ tree) to determine a bunch of elements to be skipped. However, external indexes are too heavy for a structural join and the overhead of index lookups can reduce the benefit of skipping. In this paper, we proposed element trees and distribution encoded bitmaps for efficient element skipping. With proposed techniques, we can exploit the distribution of elements as well as the context information of a query for efficient skipping of unnecessary elements.