Transaction Processing over XML (TPoX) is a computing benchmark for XML database systems. As a benchmark, TPoX is used for the performance testing of database management systems that are capable of storing, searching, modifying and retrieving XML data. The goal of TPoX is to allow database designers, developers and users to evaluate the performance of XML database features, such as the XML query languages XQuery and SQL/XML, XML storage, XML indexing, XML Schema support, XML updates, transaction processing and logging, and concurrency control. TPoX includes XML update tests based on the XQuery Update Facility.