IBM's Big SQL is their SQL for Hadoop product that allows users to run SQL queries on Hadoop data. It uses the Hive metastore to catalog table definitions and shares data logic with Hive. Big SQL is architected for high performance with a massively parallel processing (MPP) runtime and runs directly on the Hadoop cluster with no proprietary storage formats required. The document compares Big SQL to other SQL on Hadoop solutions and outlines its performance and architectural advantages.