Glossary
Massively parallel processing
An architecture that splits a query across many independent compute nodes, each processing its own data slice.
Also called: MPP, MPP database
Massively parallel processing (MPP) is a database architecture in which a query is broken up and executed simultaneously across many independent compute nodes, each with its own CPU, memory, and typically its own slice of the data, coordinated by a leader node that distributes the work and assembles the final result. It is the architecture behind most modern cloud data warehouses.
This differs from a single, powerful server scaling up, which eventually hits a hardware ceiling; MPP instead scales out by adding more nodes, and query time drops roughly in proportion to how well the data and work can be divided across them. How rows are distributed across nodes — often driven by partitioning or a hash on a key column — directly affects performance: a poor distribution key leaves some nodes idle while others do most of the work, a problem known as data skew.
MPP is what allows a warehouse to scan and aggregate billions of rows in seconds, and it pairs naturally with columnar storage, since both techniques reduce the amount of data any one node has to read. The main operational pitfall is skewed data distribution or a join on a low-cardinality key, either of which can leave the overall query waiting on one overloaded node no matter how many nodes are available.
Last reviewed September 22, 2026