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Learning PostgreSQL 10

You're reading from   Learning PostgreSQL 10 A beginner's guide to building high-performance PostgreSQL database solutions

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Product type Paperback
Published in Dec 2017
Publisher
ISBN-13 9781788392013
Length 488 pages
Edition 2nd Edition
Languages
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Authors (2):
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 Juba Juba
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Juba
 Volkov Volkov
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Volkov
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Table of Contents (23) Chapters Close

Title Page
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
1. Relational Databases FREE CHAPTER 2. PostgreSQL in Action 3. PostgreSQL Basic Building Blocks 4. PostgreSQL Advanced Building Blocks 5. SQL Language 6. Advanced Query Writing 7. Server-Side Programming with PL/pgSQL 8. OLAP and Data Warehousing 9. Beyond Conventional Data Types 10. Transactions and Concurrency Control 11. PostgreSQL Security 12. The PostgreSQL Catalog 13. Optimizing Database Performance 14. Testing 15. Using PostgreSQL in Python Applications 16. Scalability

The system catalog


PostgreSQL describes all database objects using the meta information stored in database relations. These relations hold information about tables, views, functions, indexes, foreign data wrappers (FDWs), triggers, constraints, rules, users, groups, and so on. This information is stored in the pg_catalog schema, and to make it more readable by humans, PostgreSQL also provides the information_schema schema, in which the meta information is wrapped and organized into views.

In the psql client, one can see exactly what is happening behind the scenes when a certain meta command is executed, such as \z, by enabling ECHO_HIDDEN. The ECHO_HIDDEN or -E switch allows users to study the system catalog tables of PostgreSQL. You need to run the following command:

postgres=# \set ECHO_HIDDEN
postgres=# \d 
********* QUERY **********
SELECT n.nspname as "Schema",
  c.relname as "Name",
  CASE c.relkind WHEN 'r' THEN 'table' WHEN 'v' THEN 'view' WHEN 'm' THEN 'materialized view' WHEN 'i...
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