Greenplum Database stores and processes large amounts of data by distributing the load across several servers or hosts. A logical database in Greenplum is an array of individual PostgreSQL databases working together to present a single database image. The master is the entry point to the Greenplum Database system. It is the database instance to which users connect and submit SQL statements. The master coordinates the workload across the other database instances in the system, called segments, which handle data processing and storage. The segments communicate with each other and the master over the interconnect, the networking layer of Greenplum Database.

Greenplum Database is a software-only solution; the hardware and database software are not coupled. Greenplum Database runs on a variety of commodity server platforms from Greenplum-certified hardware vendors. Performance depends on the hardware on which it is installed. Because the database is distributed across multiple machines in a Greenplum Database system, proper selection and configuration of hardware is vital to achieving the best possible performance.

This chapter describes the major components of a Greenplum Database system and the hardware considerations and concepts associated with each component: The Greenplum Master, The Segments and The Interconnect. Additionally, a system may have optional ETL Hosts for Data Loading and the Greenplum Performance Monitor for monitoring query workload and performance.