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You're reading from  Mastering PostgreSQL 15 - Fifth Edition

Product typeBook
Published inJan 2023
PublisherPackt
ISBN-139781803248349
Edition5th Edition
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Author (1)
Hans-Jürgen Schönig
Hans-Jürgen Schönig
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Hans-Jürgen Schönig

Hans-Jürgen Schönig has 20 years' experience with PostgreSQL. He is the CEO of a PostgreSQL consulting and support company called CYBERTEC PostgreSQL International GmbH. It has successfully served countless customers around the globe. Before founding CYBERTEC PostgreSQL International GmbH in 2000, he worked as a database developer at a private research company that focused on the Austrian labor market, where he primarily worked on data mining and forecast models. He has also written several books about PostgreSQL.
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Understanding execution plans

Now that we’ve dug into some important optimizations that are implemented in PostgreSQL, let’s proceed to take a closer look at execution plans. You have already seen some execution plans in this book. However, in order to make full use of plans, it is important to develop a systematic approach when it comes to reading this information.

Approaching plans systematically

The first thing you have to know is that an EXPLAIN clause can do quite a lot for you, and I highly recommend making full use of these features.

As many of you may already know, an EXPLAIN ANALYZE clause will execute the query and return the plan, including real runtime information. Here is an example:

test=# EXPLAIN ANALYZE SELECT *
FROM
(
    SELECT *
    FROM b
    LIMIT 1000000
) AS b
ORDER BY cos(bid);
                ...
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Mastering PostgreSQL 15 - Fifth Edition
Published in: Jan 2023Publisher: PacktISBN-13: 9781803248349

Author (1)

author image
Hans-Jürgen Schönig

Hans-Jürgen Schönig has 20 years' experience with PostgreSQL. He is the CEO of a PostgreSQL consulting and support company called CYBERTEC PostgreSQL International GmbH. It has successfully served countless customers around the globe. Before founding CYBERTEC PostgreSQL International GmbH in 2000, he worked as a database developer at a private research company that focused on the Austrian labor market, where he primarily worked on data mining and forecast models. He has also written several books about PostgreSQL.
Read more about Hans-Jürgen Schönig