In the final chapter of this book, you will be guided through a tool released in 2014, called walbouncer. Most of the techniques covered in this book have explained how to replicate an entire database instance, how to shard, and more. In the final chapter, which is about walbouncer, it's all about filtering the stream of the transaction log to selectively replicate database objects from one server to a set of (not necessarily identical) slaves.

The following topics will be covered in this chapter:

The walbouncer tool is available for PostgreSQL 9.4 or higher.