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Mastering PostgreSQL 12 - Third Edition
book

Mastering PostgreSQL 12 - Third Edition

by Hans-Jürgen Schönig
November 2019
Beginner to intermediate content levelBeginner to intermediate
470 pages
11h 59m
English
Packt Publishing
Content preview from Mastering PostgreSQL 12 - Third Edition

Making use of parallel queries

Starting with version 9.6, PostgreSQL supports parallel queries. This support for parallelism has been improved gradually over time, and version 11 has added even more functionality to this important feature. In this section, we will take a look at how parallelism works and what can be done to speed up things.

Before digging into the details, it is necessary to create some sample data, as follows:

test=# CREATE TABLE t_parallel AS  SELECT * FROM generate_series(1, 25000000) AS id;SELECT 25000000

After loading the initial data, we can run our first parallel query. A simple count will show what a parallel query looks like in general:

test=# explain SELECT count(*) FROM t_parallel; QUERY PLAN ------------------------------------------------------------------------------------ ...
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Publisher Resources

ISBN: 9781838988821Supplemental Content