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  • Book Overview & Buying PostgreSQL 16 Administration Cookbook
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PostgreSQL 16 Administration Cookbook

PostgreSQL 16 Administration Cookbook

By : GIANNI CIOLLI, Boriss Mejías, Jimmy Angelakos, Vibhor Kumar, Simon Riggs
4.8 (27)
Buy this Book
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PostgreSQL 16 Administration Cookbook

PostgreSQL 16 Administration Cookbook

4.8 (27)
By: GIANNI CIOLLI, Boriss Mejías, Jimmy Angelakos, Vibhor Kumar, Simon Riggs
Buy this Book

Overview of this book

PostgreSQL has seen a huge increase in its customer base in the past few years and is becoming one of the go-to solutions for anyone who has a database-specific challenge. This PostgreSQL book touches on all the fundamentals of Database Administration in a problem-solution format. It is intended to be the perfect desk reference guide. This new edition focuses on recipes based on the new PostgreSQL 16 release. The additions include handling complex batch loading scenarios with the SQL MERGE statement, security improvements, running Postgres on Kubernetes or with TPA and Ansible, and more. This edition also focuses on certain performance gains, such as query optimization, and the acceleration of specific operations, such as sort. It will help you understand roles, ensuring high availability, concurrency, and replication. It also draws your attention to aspects like validating backups, recovery, monitoring, and scaling aspects. This book will act as a one-stop solution to all your real-world database administration challenges. By the end of this book, you will be able to manage, monitor, and replicate your PostgreSQL 16 database for efficient administration and maintenance with the best practices from experts.
Table of Contents (15 chapters)
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Preface
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Preface
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Who this book is for
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What this book covers
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To get the most out of this book
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Get in touch
Free Chapter
1
First Steps
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First Steps
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Introducing PostgreSQL 16
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How to get PostgreSQL
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Connecting to the PostgreSQL server
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Enabling access for network/remote users
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Using the pgAdmin 4 GUI tool
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Using the psql query and scripting tool
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Changing your password securely
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Avoiding hardcoding your password
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Using a connection service file
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Troubleshooting a failed connection
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PostgreSQL in the cloud
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PostgreSQL with Kubernetes
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PostgreSQL with TPA
2
Exploring the Database
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Exploring the Database
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What type of server is this?
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What version is the server?
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What is the server uptime?
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Locating the database server files
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Locating the database server’s message log
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Locating the database’s system identifier
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Listing databases on the database server
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How many tables are there in a database?
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How much disk space does a database use?
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How much memory does a database currently use?
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How much disk space does a table use?
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Which are my biggest tables?
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How many rows are there in a table?
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Quickly estimating the number of rows in a table
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Listing extensions in this database
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Understanding object dependencies
3
Server Configuration
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Server Configuration
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Read the fine manual (RTFM)
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Planning a new database
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Setting the configuration parameters for the database server
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Setting the configuration parameters in your programs
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Finding the configuration settings for your session
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Finding parameters with non-default settings
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Setting parameters for particular groups of users
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A basic server configuration checklist
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Adding an external module to PostgreSQL
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Using an installed module/extension
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Managing installed extensions
4
Server Control
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Server Control
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An overview of controlling the database server
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Starting the database server manually
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Stopping the server safely and quickly
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Stopping the server in an emergency
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Reloading server configuration files
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Restarting the server quickly
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Preventing new connections
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Restricting users to only one session each
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Pushing users off the system
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Deciding on a design for multitenancy
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Using multiple schemas
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Giving users their own private databases
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Running multiple servers on one system
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Setting up a connection pool
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Accessing multiple servers using the same host and port
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Running multiple PgBouncer on the same port to leverage multiple cores
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Tables and Data
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Tables and Data
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Choosing good names for database objects
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Handling objects with quoted names
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Identifying and removing duplicates
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Preventing duplicate rows
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Finding a unique key for a set of data
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Generating test data
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Randomly sampling data
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Loading data from a spreadsheet
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Loading data from flat files
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Making bulk data changes using server-side procedures with transactions
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Dealing with large tables with table partitioning
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Finding good candidates for partition keys
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Consolidating data with MERGE
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Deciding when to use JSON data types
6
Security
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Security
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An overview of PostgreSQL security
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The PostgreSQL superuser
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Revoking user access to tables
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Granting user access to a table
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Granting user access to specific columns
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Granting user access to specific rows
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Creating a new user
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Temporarily preventing a user from connecting
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Removing a user without dropping their data
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Checking whether all users have a secure password
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Giving limited superuser powers to specific users
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Auditing database access
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Always knowing which user is logged in
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Integrating with LDAP
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Connecting using encryption (SSL / GSSAPI)
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Using SSL certificates to authenticate
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Mapping external usernames to database roles
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Using column-level encryption
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Setting up cloud security using predefined roles
7
Database Administration
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Database Administration
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Writing a script that either succeeds entirely or fails entirely
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Writing a psql script that exits on the first error
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Using psql variables
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Placing query output into psql variables
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Writing a conditional psql script
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Investigating a psql error
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Setting the psql prompt with useful information
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Using pgAdmin for DBA tasks
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Scheduling jobs for regular background execution
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Performing actions on many tables
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Adding/removing columns on a table
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Changing the data type of a column
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Changing the definition of an enum data type
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Adding a constraint concurrently
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Adding/removing schemas
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Moving objects between schemas
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Adding/removing tablespaces
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Moving objects between tablespaces
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Accessing objects in other PostgreSQL databases
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Accessing objects in other foreign databases
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Making views updatable
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Using materialized views
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Using GENERATED data columns
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Using data compression
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Monitoring and Diagnosis
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Monitoring and Diagnosis
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Cloud-native monitoring
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Providing PostgreSQL information to monitoring tools
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Real-time viewing using pgAdmin
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Monitoring the PostgreSQL message log
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Checking whether a user is connected
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Checking whether a computer is connected
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Repeatedly executing a query in psql
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Checking which queries are running
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Monitoring the progress of commands
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Checking which queries are active or blocked
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Knowing who is blocking a query
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Killing a specific session
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Knowing whether anybody is using a specific table
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Knowing when a table was last used
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Monitoring I/O statistics
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Usage of disk space by temporary data
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Understanding why queries slow down
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Analyzing the real-time performance of your queries
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Tracking important metrics over time
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Regular Maintenance
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Regular Maintenance
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Controlling automatic database maintenance
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Avoiding auto-freezing
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Removing issues that cause bloat
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Actions for heavy users of temporary tables
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Identifying and fixing bloated tables and indexes
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Monitoring and tuning a vacuum
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Maintaining indexes
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Finding unused indexes
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Carefully removing unwanted indexes
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Planning maintenance
10
Performance and Concurrency
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Performance and Concurrency
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Finding slow SQL statements
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Finding out what makes SQL slow
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Reducing the number of rows returned
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Simplifying complex SQL queries
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Speeding up queries without rewriting them
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Discovering why a query is not using an index
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Forcing a query to use an index
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Using parallel query
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Using Just-In-Time (JIT) compilation
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Creating time-series tables using partitioning
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Using optimistic locking to avoid long lock waits
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Reporting performance problems
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Backup and Recovery
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Backup and Recovery
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Understanding and controlling crash recovery
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Planning your backups
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Hot logical backup of one database
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Hot logical backup of all databases
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Backup of database object definitions
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A standalone hot physical backup
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Hot physical backups with Barman
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Recovery of all databases
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Recovery to a point in time
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Recovery of a dropped/damaged table
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Recovery of a dropped/damaged database
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Extracting a logical backup from a physical one
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Improving the performance of logical backup/recovery
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Improving the performance of physical backup/recovery
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Validating backups
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Replication and Upgrades
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Replication and Upgrades
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Replication concepts
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Replication best practices
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Setting up streaming replication
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Setting up streaming replication security
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Hot Standby and read scalability
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Managing streaming replication
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Using repmgr
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Using replication slots
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Setting up replication with TPA
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Setting up replication with CloudNativePG
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Monitoring replication
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Performance and synchronous replication (sync rep)
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Delaying, pausing, and synchronizing replication
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Logical replication
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EDB Postgres Distributed
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Archiving transaction log data
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Upgrading minor releases
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Major upgrades in-place
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Major upgrades online
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Other Books You May Enjoy
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Other Books You May Enjoy
14
Index
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Index

Placing query output into psql variables

It is also possible to store some values that have been produced by a query into variables – for instance, to reuse them later in other queries.

In this recipe, we will demonstrate this approach with a concrete example.

Getting ready

In the Controlling automatic database maintenance recipe of Chapter 9, Regular Maintenance, we will describe VACUUM, showing that it runs regularly on each table based on the number of rows that might need vacuuming (dead rows). The VACUUM command will run if that number exceeds a given threshold, which by default is just above 20% of the row count.

In this recipe, we will create a script that picks the table with the largest number of dead rows and runs VACUUM on it, assuming you have some tables already in existence.

How to do it…

The script is as follows:

SELECT schemaname
, relname
, n_dead_tup
, n_live_tup
FROM pg_stat_user_tables
ORDER BY n_dead_tup DESC
LIMIT 1
...

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