Book Image

PostgreSQL 10 Administration Cookbook - Fourth Edition

By : Simon Riggs, Gianni Ciolli
Book Image

PostgreSQL 10 Administration Cookbook - Fourth Edition

By: Simon Riggs, Gianni Ciolli

Overview of this book

PostgreSQL is a powerful, open source database management system with an enviable reputation for high performance and stability. With many new features in its arsenal, PostgreSQL 10 allows users to scale up their PostgreSQL infrastructure. This book takes a step-by-step, recipe-based approach to effective PostgreSQL administration. Throughout this book, you will be introduced to these new features such as logical replication, native table partitioning, additional query parallelism, and much more. You will learn how to tackle a variety of problems that are basically the pain points for any database administrator - from creating tables to managing views, from improving performance to securing your database. More importantly, the book pays special attention to topics such as monitoring roles, backup, and recovery of your PostgreSQL 10 database, ensuring high availability, concurrency, and replication. By the end of this book, you will know everything you need to know to be the go-to PostgreSQL expert in your organization.
Table of Contents (14 chapters)

Carefully removing unwanted indexes

Carefully removing? You mean press Enter gently after typing DROP INDEX? Err, no!

The thinking is that it takes a long time to build an index, and a short time to drop it.

What we want is a way of removing an index such that if we discover that removing it was a mistake, we can put the index back again quickly.

Getting ready

The following query will list all invalid indexes, if any:

SELECT ir.relname AS indexname 
, it.relname AS tablename
, n.nspname AS schemaname
FROM pg_index i
JOIN pg_class ir ON ir.oid = i.indexrelid
JOIN pg_class it ON it.oid = i.indrelid
JOIN pg_namespace n ON n.oid = it.relnamespace
WHERE NOT i.indisvalid;

Take note of these indexes, so that later you can tell whether...