Book Image

Mastering PostgreSQL 10

Book Image

Mastering PostgreSQL 10

Overview of this book

PostgreSQL is an open source database used for handling large datasets (big data) and as a JSON document database. This book highlights the newly introduced features in PostgreSQL 10, and shows you how you can build better PostgreSQL applications, and administer your PostgreSQL database more efficiently. We begin by explaining advanced database design concepts in PostgreSQL 10, along with indexing and query optimization. You will also see how to work with event triggers and perform concurrent transactions and table partitioning, along with exploring SQL and server tuning. We will walk you through implementing advanced administrative tasks such as server maintenance and monitoring, replication, recovery, high availability, and much more. You will understand common and not-so-common troubleshooting problems and how you can overcome them. By the end of this book, you will have an expert-level command of advanced database functionalities and will be able to implement advanced administrative tasks with PostgreSQL 10.

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Table of Contents (15 chapters)
Preface
Preface
Who this book is for
What this book covers
To get the most out of this book
Get in touch
Free Chapter
1
PostgreSQL Overview
PostgreSQL Overview
What is new in PostgreSQL 10.0?
Introducing SCRAM-SHA-256
Introducing quorum COMMIT
Introducing ICU encodings
Summary
2
Understanding Transactions and Locking
Understanding Transactions and Locking
Working with PostgreSQL transactions
Understanding basic locking
Making use of FOR SHARE and FOR UPDATE
Understanding transaction isolation levels
Observing deadlocks and similar issues
Utilizing advisory locks
Optimizing storage and managing cleanup
Summary
3
Making Use of Indexes
Making Use of Indexes
Understanding simple queries and the cost model
Improving speed using clustered tables
Understanding additional b-tree features
Introducing operator classes
Understanding PostgreSQL index types
Achieving better answers with fuzzy searching
Understanding full-text search - FTS
Summary
4
Handling Advanced SQL
Handling Advanced SQL
Introducing grouping sets
Making use of ordered sets
Understanding hypothetical aggregates
Utilizing windowing functions and analytics
Writing your own aggregates
Summary
5
Log Files and System Statistics
Log Files and System Statistics
Gathering runtime statistics
Creating log files
Summary
6
Optimizing Queries for Good Performance
Optimizing Queries for Good Performance
Learning what the optimizer does
Understanding execution plans
Understanding and fixing joins
Enabling and disabling optimizer settings
Partitioning data
Adjusting parameters for good query performance
Summary
7
Writing Stored Procedures
Writing Stored Procedures
Understanding stored procedure languages
Understanding various stored procedure languages
Improving stored procedure performance
Using stored procedures
Summary
8
Managing PostgreSQL Security
Managing PostgreSQL Security
Managing network security
Digging into row-level security - RLS
Inspecting permissions
Reassigning objects and dropping users
Summary
9
Handling Backup and Recovery
Handling Backup and Recovery
Performing simple dumps
Handling various formats
Replaying backups
Handling global data
Summary
10
Making Sense of Backups and Replication
Making Sense of Backups and Replication
Understanding the transaction log
Transaction log archiving and recovery
Setting up asynchronous replication
Upgrading to synchronous replication
Making use of replication slots
Making use of CREATE PUBLICATION and CREATE SUBSCRIPTION
Summary
11
Deciding on Useful Extensions
Deciding on Useful Extensions
Understanding how extensions work
Making use of contrib modules
Other useful extensions
Summary
12
Troubleshooting PostgreSQL
Troubleshooting PostgreSQL
Approaching an unknown database
Inspecting pg_stat_activity
Checking for slow queries
Inspecting the log
Checking for missing indexes
Checking for memory and I/O
Understanding noteworthy error scenarios
Summary
13
Migrating to PostgreSQL
Migrating to PostgreSQL
Migrating SQL statements to PostgreSQL
Moving from Oracle to PostgreSQL
Moving from MySQL or MariaDB to PostgreSQL
Summary
14
Other Books You May Enjoy
Other Books You May Enjoy
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Making use of ordered sets

Ordered sets are powerful features, but are not widely regarded as such and not widely known in the developer community. The idea is actually quite simple: data is grouped normally and then the data inside each group is ordered given a certain condition. The calculation is then performed on this sorted data.

A classic example would be the calculation of the median.

The median is the middle value. If you are, for example, earning the median income, the number of people earning less and more than you is identical. 50% of people do better and 50% of people do worse.

One way to get the median is to take sorted data and move 50% into the dataset. This is an example of what the WITHIN GROUP clause will ask PostgreSQL to do:

test=# SELECT region, 
   percentile_disc(0.5) WITHIN GROUP (ORDER BY production) 
FROM t_oil 
GROUP BY 1; 
 region         | percentile_disc...
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