mysql-binlog-connector-java

There are actually a few strong solutions out there for Mysql, most starting with change data capture like: https://github.com/shyiko/mysql-binlog-connector-java (I link that one in particular because he links to alternatives right in his readme!) Pgsql is a bit harder, but if I needed to start somewhere it would be with: https://github.com/debezium/debezium or https://github.com/confluentinc/bottledwater-pg These are the start of pretty sophisticated solutions where you need super real-time elasticsearch indexes and can bring up infra like Kafka. For many applications, queueing an update when something hits your ORM to update, with the hourly/daily refresh is pretty satisfactory.

You're quite right. Switching from a db to a log as the "master" loses the simplicity of the app-to-db model. As the article says: "For now, a better option is to extract the log from a database" - i.e you use some tooling to generate a log from the db. Indeed, you can now see tools that go in this direction usually by using the replication stream. (eg https://github.com/shyiko/mysql-binlog-connector-java and https://github.com/xstevens/decoderbufs)