When we talk about TiDB, why do we call it a distributed database? Before we dive deep into the architecture, I want to give you a quick answer to another straightforward question - why we should use TiDB? When you start to use TiDB you will soon realize following benefits. First, seamless scalability. In TiDB, all key components are decoupled with each other and support horizontal scalability. For high availability in the disaster recovery, for those stateful components, consistent data replications are supported you can achieve High Availability easily by deploying multiple such components, or achieve Disaster Recovery by deploying them across Geographic locations. Third, TiDB is actually a horizontal scalable NoSQL database with SQL and transaction compatibility. By using TiDB, you gain benefits of NoSQL and SQL at the same time. And, your database can grow into massive magnitude volume that MySQL database cannot even image. For auto sharding, the way TiDB achieves it doesn't need application changes. Last, by using TiDB and by using standard SQL only you already have the ticket to the Big Data party no ETL or extract, transformation ,load required. TiDB can almost store and retrieve any amount of data. And, it provides both row based store and the columnar store suitable for transaction processing and analytical processing at the same time. I'm going to cover it in more detail in this course later.