Django Query Optimization / select_related & prefetch_related / django-debug-toolbar / N+1 Problem

In this video, we learn about query optimization in Django, and solving the N+1 problem using the select_related() and prefetch_related() functions. We will look at how to use prefetch_related() to fetch all related objects in subsequent queries, as well as how to use select_related() to create a JOIN statement in SQL. Both methods can greatly cut down on the number of queries issued to the database, and therefore increase performance. We'll also see how to install and use django-debug-toolbar, and inspect and optimize the SQL queries via its feedback. Finally, we'll also look at Prefetch objects in Django, and how they can be used to customize the behaviour of the prefetch_related() function, as well as a quick look at the .only() function and .annotate() functions. 📌 𝗖𝗵𝗮𝗽𝘁𝗲𝗿𝘀: 00:00 Intro 00:32 Using django-debug-toolbar for SQL analysis 08:47 Using prefetch_related to optimise querying and avoid N+1 problem 14:04 Using select_related with ForeignKey objects to avoid N+1 problem 17:23 Using only() function to fetch specific fields 19:22 Prefetch objects in Django ☕️ 𝗕𝘂𝘆 𝗺𝗲 𝗮 𝗰𝗼𝗳𝗳𝗲𝗲: To support the channel and encourage new videos, please consider buying me a coffee here: https://ko-fi.com/bugbytes ▶️ Full Playlist: https://www.youtube.com/playlist?list=PL-2EBeDYMIbQXKsyNweppuFptuogJe2L- 𝗦𝗼𝗰𝗶𝗮𝗹 𝗠𝗲𝗱𝗶𝗮: 📖 Blog: https://bugbytes.io/posts/ 👾 Github: https://github.com/bugbytes-io/django-orm-series 🐦 Twitter: https://twitter.com/bugbytesio 📚 𝗙𝘂𝗿𝘁𝗵𝗲𝗿 𝗿𝗲𝗮𝗱𝗶𝗻𝗴 𝗮𝗻𝗱 𝗶𝗻𝗳𝗼𝗿𝗺𝗮𝘁𝗶𝗼𝗻: Github: https://github.com/bugbytes-io/django-orm-series django-debug-toolbar: https://django-debug-toolbar.readthedocs.io/en/latest/ prefetch_related: https://docs.djangoproject.com/en/4.2/ref/models/querysets/#prefetch-related select_related: https://docs.djangoproject.com/en/4.2/ref/models/querysets/#select-related QuerySet only() function: https://docs.djangoproject.com/en/4.2/ref/models/querysets/#only Serving Static Files During Development: https://docs.djangoproject.com/en/4.2/howto/static-files/#serving-static-files-during-development #python #django #webdevelopment #database #sql