Preface

PostgreSQL is an advanced SQL database server, available on a wide range of platforms and is fast becoming one of the world's most popular server databases with an enviable reputation for performance, stability, and an enormous range of advanced features. PostgreSQL is one of the oldest open source projects, completely free to use, and developed by a very diverse worldwide community. Most of all, it just works!

One of the clearest benefits of PostgreSQL is that it is open source, meaning that you have a very permissive license to install, use, and distribute PostgreSQL without paying anyone any fees or royalties. On top of that, PostgreSQL is well-known as a database that stays up for long periods, and requires little or no maintenance in many cases. Overall, PostgreSQL provides a very low total cost of ownership.

PostgreSQL Administration Cookbook offers the information you need to manage your live production databases on PostgreSQL. The book contains insights direct from the main author of the PostgreSQL replication and recovery features and the rest of the team at 2ndQuadrant. This hands-on guide will assist developers working on live databases, supporting web or enterprise software applications using Java, Python, Ruby, and .Net from any development framework. It's easy to manage your database when you've got PostgreSQL 9 Administration Cookbook at hand.

This practical guide gives you quick answers to common questions and problems, building on the author's experience as trainers, users, and core developers of the PostgreSQL database server.

Each technical aspect is broken down into short recipes that demonstrate solutions with working code, and then explain why and how that works. The book is intended to be a desk reference for both new users and technical experts.

The book covers all the latest features available in PostgreSQL 9. Soon you will be running a smooth database with ease!

What this book covers

Chapter 1, First Steps, covers topics such as an introduction to PostgreSQL 9, downloading and installing PostgreSQL 9, connecting to a PostgreSQL server, enabling server access to network/remote users, using graphical administration tools, using psql query and scripting tools, changing your password securely, avoiding hardcoding your password, using a connection service file, and troubleshooting a failed connection.

Chapter 2, Exploring the Database, helps you identify the version of the database server you are using and also the server uptime. It helps you locate the database server files, database server message log, and database's system identifier. It lets you list a database on the database server, contains recipes that let you know the number of tables in your database, how much disk space is used by the database and tables, which are the biggest tables, how many rows a table has, how to estimate rows in a table, and how to understand object dependencies.

Chapter 3, Configuration, covers topics such as reading the fine manual (RTFM), planning a new database, changing parameters in your programs, the current configuration settings, parameters that are at non-default settings, updating the parameter file, setting parameters for particular groups of users, basic server configuration checklist, adding an external module into the PostgreSQL server, and running the server in power saving mode.

Chapter 4, Server Control, provides information about starting the database server manually, stopping the server quickly and safely, stopping the server in an emergency, reloading the server configuration files, restarting the server quickly, preventing new connections, restricting users to just one session each, and pushing users off the system. It contains recipes that help you decide on a design for multi-tenancy, how to use multiple schemas, giving users their own private database, running multiple database servers on one system, and setting up a connection pool.

Chapter 5, Tables and Data, guides you through the process of choosing good names for database objects, handling objects with quoted names, enforcing same name, same definition for columns, identifying and removing duplicate rows, preventing duplicate rows, finding a unique key for a set of data, generating test data, randomly sampling data, loading data from a spreadsheet, and loading data from flat files.

Chapter 6, Security, provides recipes on revoking user access to a table, granting user access to a table, creating a new user, temporarily preventing a user from connecting, removing a user without dropping their data, checking whether all users have a secure password, giving limited superuser powers to specific users, auditing DDL changes, auditing data changes, integrating with LDAP, connecting using SSL, and encrypting sensitive data.

Chapter 7, Database Administration, provides recipes on useful topics such as writing a script wherein either all succeed or all fail, writing a psql script that exits on the first error, performing actions on many tables, adding/removing columns on tables, changing the data type of a column, adding/removing schemas, moving objects between schemas, adding/removing tablespaces, moving objects between tablespaces, accessing objects in other PostgreSQL databases, and making views updateable.

Chapter 8, Monitoring and Diagnosis, provides recipes that answer questions such as is the user connected?, what are they running?, are they active or blocked?, who is blocking them?, is anybody using a specific table?, when did anybody last use it?, how much disk space is used by temporary data?, and why are my queries slowing down? It also helps you in investigating and reporting a bug, producing a daily summary report of logfile errors, killing a specific session, and resolving an in-doubt prepared transaction.

Chapter 9, Regular Maintenance, provides useful recipes on controlling automatic database maintenance, avoiding auto freezing and page corruptions, avoiding transaction wraparound, removing old prepared transactions, actions for heavy users of temporary tables, identifying and fixing bloated tables and indexes, maintaining indexes, finding unused indexes, carefully removing unwanted indexes, and planning maintenance.

Chapter 10, Performance and Concurrency, covers topics such as finding slow SQL statements, collecting regular statistics from pg_stat* views, finding what makes SQL slow, reducing the number of rows returned, simplifying complex SQL, speeding up queries without rewriting them, why is my query not using an index?, how do I force a query to use an index?, using optimistic locking, and reporting performance problems. And of course, the new parallel query features.

Chapter 11, Backup and Recovery, insists that backups are essential, though they also devote only a very small amount of time to thinking about the topic. So, this chapter provides useful information about backup and recovery of your PostgreSQL database through recipes on understanding and controlling crash recovery, planning backups, hot logical backup of one database, hot logical backup of all databases, hot logical backup of all tables in a tablespace, backup of database object definitions, standalone hot physical database backup, hot physical backup and continuous archiving. It also includes topics such as recovery of all databases, recovery to a point in time, recovery of a dropped/damaged table, recovery of a dropped/damaged database, recovery of a dropped/damaged tablespace, improving performance of backup/recovery, and incremental/differential backup and restore.

Chapter 12, Replication and Upgrades, explains that replication isn't magic, though it can be pretty cool. It's even cooler when it works, and that's what this chapter is all about. This chapter covers replication concepts, replication best practices, setting up file-based log shipping replication, setting up streaming log replication, managing log shipping replication, managing Hot Standby, synchronous replication, upgrading to a new minor release , in-place major upgrades, major upgrades online, plus logical replication and Postgres-BDR.

What you need for this book

We need the following software for this book:

• PostgreSQL 9.5 or PostgreSQL 9.6 Server Software
• psql client utility (part of 9.6)
• pgAdmin4

Who this book is for

This book is for system administrators, database administrators, architects, developers, and anyone with an interest in planning for or running live production databases. This book is most suited to those who have some technical experience.

Sections

In this book, you will find several headings that appear frequently (Getting ready, How to do it, How it works, There's more, and See also).

To give clear instructions on how to complete a recipe, we use these sections as follows:

Getting ready

This section tells you what to expect in the recipe, and describes how to set up any software or any preliminary settings required for the recipe.

How to do it…

This section contains the steps required to follow the recipe.

How it works…

This section usually consists of a detailed explanation of what happened in the previous section.

There's more…

This section consists of additional information about the recipe in order to make the reader more knowledgeable about the recipe.

See also

This section provides helpful links to other useful information for the recipe.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "In PostgreSQL 9.6, the utility pg_Standby is no longer required, as many of its features are now performed directly by the server."

A block of code is set as follows:

CREATE USER repuser
       SUPERUSER
       LOGIN
       CONNECTION LIMIT 1
       ENCRYPTED PASSWORD 'changeme';

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

SELECT *FROM mytable
 WHERE  (col1, col2, … ,colN) IN
 (SELECT col1, col2, … ,colN
  FROM mytable
  GROUP BY col1, col2, … ,colN
  HAVING count(*) > 1);

Any command-line input or output is written as follows:

$ postgres --single -D /full/path/to/datadir postgres

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: " The Query tool has a good looking visual explain feature as well as a Graphical Query Builder, as shown in the following screenshot".

Note

Warnings or important notes appear in a box like this.

Note

Tips and tricks appear like this.

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