A Selective Key-Oriented XML Index for the Index Selection Problem in XDBMS

In relational database management systems indexes are used to accelerate specific queries. The selection of indexes is an important task when tuning a database which is performed by a database administrator or an index propagation tool which suggests a set of suitable indexes. In this paper we introduce a new index approach, called keyoriented XML index (KeyX), that uses specific XML element or attribute values as keys referencing arbitrary nodes in the XML data. KeyX is selective to specific queries avoiding efforts spent for elements which are never queried. This concept reduces memory consumption and unproductive index updates. We transfer the Index Selection Problem (ISP) to XDBMS. Applying the ISP, a workload of database operations is analyzed and a set of selective indexes that minimizes the total execution time for the workload is suggested. Because the workload is analyzed periodically and suitable indexes are created or dropped automatically our implementation of KeyX guarantees high performance over the total life time of a database.