Book Image

PostgreSQL 9 High Availability Cookbook

By : Shaun Thomas
Book Image

PostgreSQL 9 High Availability Cookbook

By: Shaun Thomas

Overview of this book

A comprehensive series of dependable recipes to design, build, and implement a PostgreSQL server architecture free of common pitfalls that can operate for years to come. Each chapter is packed with instructions and examples to simplify even highly complex database operations. If you are a PostgreSQL DBA working on Linux systems who want a database that never gives up, this book is for you. If you've ever experienced a database outage, restored from a backup, spent hours trying to repair a malfunctioning cluster, or simply want to guarantee system stability, this book is definitely for you.
Table of Contents (12 chapters)
11
Index

Using a foreign table in a query

Foreign tables exist as empty shells on the local database, lending merely their structure for query-planning and data-fetching purposes. The foreign data wrapper transforms data requests to something the remote server can understand and presents it in a way PostgreSQL will recognize.

As we're using the postgres_fdw wrapper, the situation is simplified. A PostgreSQL server should have less trouble communicating with another PostgreSQL server than an Oracle server, for instance. Though this means less transformation, there are still limitations to what functionality a foreign table might provide compared to a local table.

In this recipe, we'll use a foreign table in a few scenarios and examine how it performs in each. We'll also explore some of the common caveats involved in foreign table access.

Getting ready

As we will be using the pgbench_accounts foreign table in this recipe, please follow all the previous recipes before proceeding.

How to do...