A parallel database system seeks to improve performance through parallelization of various operations, such as loading data, building indexes and evaluating queries. A Computer Database is a structured collection of records or data that is stored in a computer system Parallel computing is a form of computation in which many instructions are carried out simultaneously operating on the principle that large problems can often Although data may be stored in a distributed fashion, the distribution is governed solely by performance considerations. Parallel database improves processing and input/output speeds by using multiple CPUs and disks in parallel. In Computing, input/output, or I/O, refers to the communication between an Information processing system (such as a Computer) and the outside Centralized and client-server database systems are not powerful enough to handle such applications. The client-server Software architecture model distinguishes client systems from server systems which communicate over a Computer network In parallel processing, many operations are performed simultaneously, as opposed to serial processing, in which the computational steps are performed sequentially.