The XPS Approach to Loading and Unloading Terabyte Databases

The loader was developed on top of the existing Parallel Data Query (PDQ) iterator infrastructure. The loader and converter are iterators. The server treats the load iterator tree just like any other iterator tree and is able to use existing algorithms for parallelization and resource allocation. This also allows the loader functionality to have low level access to SQL functions. The XPS loader design introduces the concept of an external table a table that has a catalog entry in a database but does not reside in a materialized form within that database. Any source for a load or target for an unload can be treated as an external table. That is, an external table can be used as an interface to an application program or system device that is external to the server. To create an external table, one uses our extended create table or select. . _ into. . . statement syntax.