Book Image

PostgreSQL Administration Cookbook, 9.5/9.6 Edition - Third Edition

Book Image

PostgreSQL Administration Cookbook, 9.5/9.6 Edition - Third Edition

Overview of this book

PostgreSQL is a powerful opensource database management system; now recognized as the expert's choice for a wide range of applications, it has an enviable reputation for performance and stability. PostgreSQL provides an integrated feature set comprising relational database features, object-relational, text search, Geographical Info Systems, analytical tools for big data and JSON/XML document management. Starting with short and simple recipes, you will soon dive into core features, such as configuration, server control, tables, and data. You will tackle a variety of problems a database administrator usually encounters, from creating tables to managing views, from improving performance to securing your database, and from using monitoring tools to using storage engines. Recipes based on important topics such as high availability, concurrency, replication, backup and recovery, as well as diagnostics and troubleshooting are also given special importance. By the end of this book, you will have all the knowledge you need to run, manage, and maintain PostgreSQL efficiently.
Table of Contents (13 chapters)

Using parallel query

PostgreSQL 9.6 introduces parallel query, after many years of development.

Response times from long running queries can be improved by the use of parallel processing. The concept is that we divide a large task up into multiple smaller pieces. We get the answer faster, but we use more resources to do that.

Very short queries won't get faster by using parallel query, so you'll gain more by thinking about better indexing strategies.

How to do it...

Take a query that needs to do a big chunk of work, such as this:

\timing
SELECT count(*) FROM accounts;
count
---------
1000000
(1 row)
Time: 261.652 ms
SET max_parallel_workers_per_gather = 8;
SELECT count(*) FROM accounts;
count
---------
1000000
(1 row)
Time: 180...