The purpose of the tutorial is to outline the basics of parallel database systems technologies. Particular attention is paid to the implementation of DBMS for cluster systems. Provides a classification of known forms of parallel transaction processing. Comparative analysis of various architectures of parallel database systems is given. Possible technological approaches to the organization of parallel processing of requests are considered. The iterative model, synchronous and asynchronous pipelines are discussed. Describes methods for fragmenting data and how to organize interprocessor exchanges. An approach is proposed to automatically convert a sequential query execution plan into a parallel one. Much attention is paid to modeling parallel database systems and organizing efficient buffering in conditions of using fragmented parallelism. The book is aimed at undergraduates, graduate students and scientists specializing in the development of technologies for parallel database systems and their application to process ultra-large amounts of data on modern multi-core and multiprocessor systems with a cluster architecture.