What PDQ is
Parallel database query (PDQ) is a database server feature that can improve performance dramatically when the server processes queries that decision-support applications initiate. PDQ enables OneDB to distribute the work for one aspect of a query among several processors. For example, if a query requires an aggregation, OneDB can distribute the work for the aggregation among several processors.
PDQ also includes tools for resource management.
Another database server feature, table fragmentation, allows you to store the parts of a table on different disks. PDQ delivers maximum performance benefits when the data that you query is in fragmented tables. For information about how to use fragmentation for maximum performance, see Planning a fragmentation strategy.