A MySQL binary log is a binary log file that is provided by MySQL to record changes in data. A MySQL binary log can be regarded as a message queue. The queue stores detailed incremental change information in MySQL in chronological order. Downstream systems or tools consume the change entries in the queue to synchronize data from MySQL in real time. This mechanism is also referred to as change data capture (CDC).
CDC can be used to synchronize data to third-party systems. PolarDB-X CDC also allows you to deploy an active geo-redundancy architecture for your business. For example, users are granted write permissions on different data centers based on the areas to which the users belong. This way, each user can write data only in permitted data centers. For read operations, each user can read data from the replica that is in close proximity to the geographical area where the user is located. This is because PolarDB-X uses CDC to synchronize data to the replicas when the data is written to a data center.