Book Image

Mastering PostgreSQL 9.6

By : Hans-Jürgen Schönig
Book Image

Mastering PostgreSQL 9.6

By: Hans-Jürgen Schönig

Overview of this book

PostgreSQL is an open source database used for handling large datasets (Big Data) and as a JSON document database. It also has applications in the software and web domains. This book will enable you to build better PostgreSQL applications and administer databases more efficiently. We begin by explaining the advanced database design concepts in PostgreSQL 9.6, 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 and high availability, and much more. You will understand the 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 the advanced database functionalities and will be able to implement advanced administrative tasks with PostgreSQL.
Table of Contents (14 chapters)
Free Chapter
PostgreSQL Overview

Inspecting pg_stat_activity

The first thing I recommend is checking out pg_stat_statements. Answer the following questions:

How many concurrent queries are currently executed on your system?

  • Do you see similar types of queries showing up in the query column all the time?
  • Do you see queries that have been running for a long time?
  • Are there any locks that have not been granted?
  • Do you see connections from suspicious hosts?

The pg_stat_activity view should always be checked first because it will give you an idea of what is happening on the system. Of course, graphical monitoring is supposed to give you a first impression of the system. However, at the end of the day, it really boils down to the queries actually running on the server. Therefore, a good overview of the system provided by pg_stat_activity is more than vital for tracking down issues.

To make it easier for you, I have compiled a couple of queries that...