Postgres for Developers

Using Postgres effectively in your application — indexing strategies, query patterns, schema design, and framework integrations.

All categories

Replacing Oracle Hints: Best Practices with pg_hint_plan on PostgreSQL

05 February, 2025

If you're migrating from Oracle Database to PostgreSQL, you're likely accustomed to using hints to optimize queries. In Oracle, these are special directives embedded in SQL (like ) that steer the optimizer's execution plan. They can be extremely useful but also introduce complexity and “hint debt” over time. PostgreSQL takes a very different approach to query optimization. Rather than supporting built-in hints, the Postgres community, historically, has emphasized relying on its cost-based…

The Fastest Way To Load Data Into Postgres With Ruby on Rails

14 December, 2021

Data migration is a delicate and sometimes complicated and time-consuming process. Whether you are loading data from a legacy application to a new application or you just want to move data from one database to another, you’ll most likely need to create a migration script that will be accurate, efficient, and fast to help with the process — especially if you are planning to load a huge amount of data. There are several ways you can load data from an old Rails app or other application to Rails. In…

Postgres Views in Django

16 November, 2021

At my first job, we worked with a lot of data. I quickly found that when there's a lot of data, there are bound to be some long, convoluted SQL queries. Many of ours contained multiple joins, conditionals, and filters. One of the ways we kept the complexity manageable was to create Postgres views for common queries. Postgres views allow you to query against the results of another query. Views can be composed of columns from one or more tables or even other views, and they are easy to work with…

Efficient Pagination: PostgreSQL and Django

20 July, 2021

You could say most web frameworks take a naive approach to pagination. Using PostgreSQL’s COUNT, LIMIT, and OFFSET features for pagination works fine for the majority of web applications, but if you have tables with a million records or more, performance degrades quickly. Django is an excellent framework for building web applications, but its default pagination method falls into this trap at scale. In this article, I’ll help you understand Django’s pagination limitations and offer three…

PostgreSQL Partitioning in Django

08 July, 2021

Postgres 10 introduced partitioning to improve performance for very large database tables. You will typically start to see the performance benefits with tables of 1 million or more records, but the technical complexity usually doesn’t pay off unless you’re dealing with hundreds of gigabytes of data. Though there are several advantages to partitioning, it requires more tables, which can become cumbersome to work with, especially if you change your data structure in the future. Please note: If you…

GeoDjango and PostGIS in Django

24 June, 2021

In this article, I’ll introduce you to spatial data in PostgreSQL and Django. You’ll learn how to use PostGIS and GeoDjango to create, store, and manipulate geographic data (both raster and vector) in a Python web application. Spatial data is any geographic data that contains information related to the earth, such as rivers, boundaries, cities, or natural landmarks. It describes the contours, topology, size, and shape of these features. Maps are a common method of visualizing spatial data, which…

Using Postgres Row-Level Security in Ruby on Rails

25 May, 2021

Securing access to your Postgres database is more important than ever. With applications growing more complex, often times using multiple programming languages and frameworks within the same app, it can be challenging to ensure access to customer data is handled consistently. For example, if you are building a SaaS application where different companies use the application, you don't want users of Company A to see the data of users in Company B by accident. Sure, you could use create a separate…

Creating Custom Postgres Data Types in Rails

22 April, 2021

Postgres ships with the most widely used common data types, like integers and text, built in, but it's also flexible enough to allow you to define your own data types if your project demands it. Say you're saving price data and you want to ensure that it’s never negative. You might create a type that you could then use to define columns on multiple tables. Or maybe you have data that makes more sense grouped together, like GPS coordinates. Postgres allows you to create a type to hold that data…

Efficient Postgres Full Text Search in Django

24 February, 2021

In this article, we'll take a look at making use of the built-in, natural language based Postgres Full Text Search in Django. Internet users have gotten increasingly discerning when it comes to search. When they type a keyword into your website's search bar, they expect to find logically ranked results, including related matches and misspellings. Because users are used to these sophisticated search systems, developers have to build applications that use more than simple queries. Postgres Full…

Creating Custom Postgres Data Types in Django

15 December, 2020

Postgres allows you to define custom data types when the default types provided don't fit your needs. There are many situations where these custom data types come in handy. For example, if you have multiple columns in several tables that should be an between 0 and 255, you could use a custom data type so that you only have to define the constraints once. Or, if you have complex data - like metadata about a file - and you want to save it to a single column instead of spreading it across several…

PostGIS vs. Geocoder in Rails

01 October, 2020

This article sets out to compare PostGIS in Rails with Geocoder and to highlight a couple of the areas where you'll want to (or need to) reach for one over the other. I will also present some of the terminology and libraries that I found along the way of working on this project and article as I set out to understand PostGIS better and how it is integrated with Rails. If you are interested in learning how to work with geospatial data with PostGIS in Django I recommend having a look at our blog…

Using Postgres Row-Level Security in Python and Django

13 August, 2020

Postgres introduced row-level security in 2016 to give database administrators a way to limit the rows a user can access, adding an extra layer of data protection. What's nice about RLS is that if a user tries to select or alter a row they don't have access to, their query will return 0 rows, rather than throwing a permissions error. This way, a user can use , and they will only receive the rows they have access to with no knowledge of rows they don't. Most examples of RLS limit row access by…

Postgres JSONB Fields in Django

30 July, 2020

I remember the first time I built user preferences into an app. At first, users just needed to be able to opt in or out of our weekly emails. "No big deal," I thought, "I'll just add a new field on the Users table." For a while, that was fine. A few weeks later, my boss asked me if we could let users opt into push notifications. Fine, that's just one more column on the database. Can't hurt, right? You probably see where this is going. Within months, my user table had 40 columns, and while…

Advanced Active Record: Using Subqueries in Rails

24 June, 2020

Active Record provides a great balance between the ability to perform simple queries simply, and also the ability to access the raw SQL sometimes required to get our jobs done. In this article, we will see a number of real-life examples of business needs that may arise at our jobs. They will come in the form of a request for data from someone else at the company, where we will first translate the request into SQL, and then into the Rails code necessary to find those records. We will be covering…

Full Text Search in Milliseconds with Rails and PostgreSQL

16 April, 2020

Imagine the following scenario: You have a database full of job titles and descriptions, and you’re trying to find the best match. Typically you’d start by using an ILIKE expression, but this requires the search phrase to be an exact match. Then you might use trigrams, allowing spelling mistakes and inexact matches based on word similarity, but this makes it difficult to search using multiple words. What you really want to use is Full Text Search, providing the benefits of ILIKE and trigrams…

Effectively Using Materialized Views in Ruby on Rails

16 January, 2020

It's every developer's nightmare: SQL queries that get large and unwieldy. This can happen fairly quickly with the addition of multiple joins, a subquery and some complicated filtering logic. I have personally seen queries grow to nearly one hundred lines long in both the financial services and health industries. Luckily Postgres provides two ways to encapsulate large queries: Views and Materialized Views. In this article, we will cover in detail how to utilize both views and materialized views…

Similarity in Postgres and Rails using Trigrams

19 November, 2019

You typed "postgras", did you mean "postgres"? Use the best tool for the job. It seems like solid advice, but there's something to say about keeping things simple. There is a training and maintenance cost that comes with supporting an ever growing number of tools. It may be better advice to use an existing tool that works well, although not perfect, until it hurts. It all depends on your specific case. Postgres is an amazing relational database, and it supports more features than you might…

Efficient GraphQL queries in Ruby on Rails & Postgres

24 September, 2019

GraphQL puts the user in control of their own destiny. Yes, they are confined to your schema, but beyond that they can access the data in any which way. Will they ask only for the "events", or also for the "category" of each event? We don't really know! In REST based APIs we know ahead of time what will be rendered, and can plan ahead by generating the required data efficiently, often by eager-loading the data we know we'll need. In this article, we will discuss what N+1 queries are, how they…