TiDB, an open-source NewSQL database, features horizontal scalability, which shelters users from the complexity of cross-shard queries and operations. However, when users migrate from a sharding solution to TiDB, the complexity is still there. The TiDB Data Migration (DM) tool supports full data migration and incremental data replication from sharding databases to TiDB.
This article explains how Sync, DM’s core component, processes Data Manipulation Language (DML) statements through the binlog replication workflow. It covers how Sync reads, filters, routes, converts binlog events, and optimizes executions.