TiDB Distributed SQL Database

TiDB is an open-source distributed SQL database compatible with MySQL protocol, supporting horizontal scaling and strong consistency transactions. Created by PingCAP in 2015, it features an HTAP (Hybrid Transactional and Analytical Processing) architecture. Key components: TiDB Server handles SQL parsing and execution with MySQL 5.7 compatibility. TiKV distributed key-value storage engine uses Raft consensus for strongly consistent multi-replica replication with automatic sharding and horizontal scaling. TiFlash columnar storage engine provides real-time analytics via Raft Learner asynchronous replication keeping row and column stores in sync. Distributed transactions support both optimistic and pessimistic locking via Percolator model for ACID guarantees. Horizontal scalability with automatic data sharding and load balancing supporting petabyte-scale data. MySQL ecosystem compatibility including JSON, window functions, CTEs, and partitioned tables. TiDB Cloud provides fully managed cloud service with Serverless Tier for elastic scaling. HTAP enables one database for both transactional and analytical workloads without ETL pipelines. Over 37k GitHub stars, widely used in finance, e-commerce, logistics, and gaming. Compatible with Spark, Flink big data ecosystem with CDC Change Data Capture for real-time sync.