Two Approaches to Synchronize MySQL Data with Redis Cache: Trigger + UDF and Binlog Parsing (Canal)

This article introduces two solutions for synchronizing MySQL data with Redis cache.

Solution 1 (UDF) : Use MySQL triggers to detect data changes, invoke a custom UDF function that writes the changed data directly to Redis. Suitable for read‑heavy, low‑write scenarios; not ideal when the table experiences frequent writes due to trigger overhead.

Diagram and sample code illustrate the trigger definition and UDF implementation.

Solution 2 (Binlog Parsing) : Parse MySQL binary logs to capture changes and write them into Redis, effectively treating MySQL as the master and Redis as the slave. This requires deep understanding of binlog formats (Statement/Row/Mixed) and considerable implementation effort.

The article also presents Alibaba’s open‑source Canal project, which simulates a MySQL slave to receive binlog streams, parses them, and allows custom processing before persisting to Redis.

Additional notes discuss the pitfalls of reverse synchronization (Redis → MySQL) and emphasize data safety concerns.