“Dataquest is my favorite learning platform because you are not just given answers immediately when you’re working on the code — instead, you’re cracking the brain to understand and remember.”

Rahila Hashim

Data Scientist @ClinFocus

Course overview

In this course, you’ll learn how to write database descriptions. You’ll discover how to manage meta information about databases and tables by using PostgreSQL Internals. You’ll also learn how to debug your PostgreSQL queries using the EXPLAIN clause.

You’ll learn how to measure estimated and actual execution times of your queries and determine which SQL clause is the most computationally expensive to perform, as well as the biggest cause for long-running queries. You’ll learn concepts such as indexing and how it can greatly reduce querying speed.

You’ll also learn what it means to vacuum a PostgreSQL database, how it reduces query speeds, and how to vacuum a database, as well as what ACID means for database transactions and why it’s important for transaction blocks.

Best of all, you’ll learn by doing — you’ll practice and get feedback directly in the browser.

Key skills

  • Applying the fundamentals of PostgreSQL’'s internal tooling
  • Debugging PostgreSQL queries and finding bottlenecks
  • Using indices to optimize PostgreSQL queries

Course outline

Optimizing PostgreSQL Databases [5 lessons]

Exploring Postgres Internals 2h

Lesson Objectives
  • Manage meta information about databases and tables using Postgres
  • Define a Postgres schema
  • Create a description of a database

Debugging Postgres Queries 1h

Lesson Objectives
  • How to debug Postgres queries
  • How to measure estimated and actual execution times

Using an Index 1h

Lesson Objectives
  • Speed up common queries using an index
  • Build an index table
  • Measure query speeds

Advanced Indexing 1h

Lesson Objectives
  • Create a multiple column index
  • Identify different types of indexes
  • Order your index columns

Vacuuming Postgres Databases 1h

Lesson Objectives
  • Define a database vacuum
  • Define a transaction block
  • Define ACID for database transactions

The Dataquest guarantee


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We believe so strongly in our paths that we offer a full satisfaction guarantee. If you complete a career path on Dataquest and aren’t satisfied with your outcome, we’ll give you a refund.

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Challenge yourself with exercises

Challenge yourself with exercises

Work with real data from day one with interactive lessons and hands-on exercises.

Showcase your path certification

Showcase your path certification

Impress employers by completing a capstone project and certifying it with an expert review.

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Aaron Melton

Business Analyst at Aditi Consulting

“Dataquest starts at the most basic level, so a beginner can understand the concepts. I tried learning to code before, using Codecademy and Coursera. I struggled because I had no background in coding, and I was spending a lot of time Googling. Dataquest helped me actually learn.”


Jessica Ko

Machine Learning Engineer at Twitter

“I liked the interactive environment on Dataquest. The material was clear and well organized. I spent more time practicing then watching videos and it made me want to keep learning.”


Victoria E. Guzik

Associate Data Scientist at Callisto Media

“I really love learning on Dataquest. I looked into a couple of other options and I found that they were much too handhold-y and fill in the blank relative to Dataquest’s method. The projects on Dataquest were key to getting my job. I doubled my income!”

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