Redshift is Amazon's fully managed data warehouse that uses PostgreSQL as its foundation. It provides fast analytics on petabyte-scale datasets through its columnar storage format, data compression techniques, and massively parallel processing architecture. Redshift achieves high performance by distributing data and queries across multiple compute nodes, storing data in columns rather than rows for efficient scanning, and compressing data using techniques like run-length encoding. Users must choose an appropriate sort key and distribution key to optimize query performance.