YugabyteDB's YSQL is designed to support PostgreSQL-compatible distributed SQL workloads while leveraging the existing open-source Postgres codebase for a high degree of support and accelerated time-to-market. YugabyteDB achieves this by utilizing its common distributed storage engine, which powers both SQL and NoSQL applications, allowing it to scale out linearly on demand. The system uses DocDB as a persistent "key to object/document" store on each node, supporting efficient fine-grained attribute updates and lookups while handling many terabytes of data per node. YugabyteDB's YQL layer implements the server-side of multiple protocols/APIs that support various use cases, including PostgreSQL wire-protocol for production usage. The system supports distributed ACID transactions, enabling features such as strongly consistent secondary indexes and multi-table/row ACID operations in the YSQL context.