DbSchema | How to Create an Index in PostgreSQL?

PostgreSQL • 16-May-2023

by Malik Umair Sajjad

Table of Contents

Introduction
Understanding Indexes
Prerequisites
Creating an Index in PostgreSQL
1. Using psql
2. Using DbSchema
Conclusion
References

Introduction

Database management and optimization is a critical aspect of any data-driven application. One of the most effective ways to improve database performance is by utilizing indexes. In this tutorial, we will delve into the concept of an index and guide you on how to create one in PostgreSQL using both psql and DbSchema.

Understanding Indexes

Concept of Indexes

An index, in the context of databases, is a data structure that enhances the speed of data retrieval operations on a database table. Similar to an index in a book, which lets you quickly locate information without having to read every page, a database index allows the database program to find data quickly without scanning every row in a table.

Benefits of Indexes

Efficient data retrieval: Indexes accelerate the data retrieval process, making your applications faster and more efficient.
Data sorting: Indexes can efficiently order the data, thereby speeding up the data sorting process.
Data Integrity: Some types of indexes, like unique indexes, help maintain data integrity by ensuring that the indexed columns do not store duplicate values.

Limitations of Indexes

Increased storage requirements: Each additional index consumes more storage space as it is stored separately from the table.
Performance overhead for write operations: While indexes speed up data retrieval, they can slow down write operations (insert, delete, update) as every change in the indexed column requires an update to the index.

Unique Index

A __UNIQUE index ensures that the indexed columns do not store duplicate values. It is a way of enforcing uniqueness in a table's column. UNIQUE index on mandatory columns is equivalent to a __Primary Key (PK) .

The syntax to create a __UNIQUE` index is:

1	CREATE UNIQUE INDEX index_name ON table_name(column_name);

Index Parameters

Here is an overview of some commonly used __index parameters` in PostgreSQL:

Parameter	Description
__UNIQUE`	Enforces uniqueness of the indexed data.
__CONCURRENTLY`	Allows the index to be built without locking out writes.
__IF NOT EXISTS`	Prevents an error if the index already exists.
__INCLUDE`	Includes non-key columns in the index.
__name`	Specifies the name of the index.
__ONLY`	If set, only that table is indexed; not any of its child tables.

Index Storage Parameters

Here are some of the storage parameters that you can use while creating an index:

Parameter	Description
__fillfactor`	Specifies what percentage of space on a page to be filled with data, leaving the rest for updates.
__deduplicate_items`	Controls whether item pointers are deduplicated.
__buffering`	Enables or disables buffering build of a GiST index.
__fastupdate`	Enables or disables “fast update” option for a GiST index.
__gin_pending_list_limit`	Sets the maximum size of the pending list for GIN indexes.
__pages_per_range`	Defines the number of pages that a single FSM record can represent in a BRIN index.
__autosummarize`	Controls automatic summarization for text search in a GIN index.

Prerequisites

Before proceeding, ensure you have the following:

Access to a PostgreSQL database, with necessary privileges to create an index.
Familiarity with SQL.
DbSchema installed on your machine, if you opt to use DbSchema.

For installation and establishing connection refer to PostgreSQL-How to create a database?

Creating an Index in PostgreSQL

Using psql

To create an index in PostgreSQL via the psql command-line interface, follow these steps:

Log in to PostgreSQL:

__shell psql -U username -d databasename __
Create an index on a table of your choice. For example, to create an index on the __email column of the __users table, execute:

__sql CREATE INDEX idx_users_email ON users(email); __

This command will create an index named __idx_users_email on the __email column in the __users` table.

To create a table in psql refer to PostgreSQL-How to Create a Table?

Using DbSchema

To create an index in PostgreSQL using the DbSchema GUI, follow these steps:

Launch DbSchema and connect to your PostgreSQL database.
Once connected, navigate to your desired table from the left panel.
On the table’s page, switch to the ‘Indexes’ tab.
Click on the ‘Add Index’ button, provide a name for your index, and select the columns to be indexed.
Save your changes to create the index.

Create Tables and Visually Manage PostgreSQL using DbSchema

DbSchema is a PostgreSQL client and visual designer. DbSchema has a free Community Edition, which can be downloaded here.

Create Index

Start the application and connect to the Postgres database. Navigate to the desired table and switch to Indexes tab.

Conclusion

While indexes in PostgreSQL are powerful tools that can substantially boost the performance of your database queries, they also come with their own set of considerations. It is crucial to strike a balance in their use, taking into account the specific needs of your application. In this guide, we covered the process of creating an index using both the psql command-line interface and the DbSchema GUI, providing you with the flexibility to choose the method that suits your needs best. Keep exploring, and optimize your database performance effectively!