Avoid n+1 queries on Rails
by
benito serna
Master n+1 queries identification, preloading, counts and counter caches, and eliminate n+1 queries from your code.
What is “Avoid n+1 queries on Rails” about?
Master n+1 queries identification, preloading, counts and counter caches, and eliminate n+1 queries from your code
Who should read “Avoid n+1 queries on Rails”?
For beginner programmers
What will you learn in “Avoid n+1 queries on Rails”
You will learn:
- What is an n+1 queries problem
- When a query will be executed
- How to preload direct associations
- How to preload nested associations
- When should you use the different preloading methods
- What is the difference between joins and preload
- What is the difference between count, size and length
- How to preload just the counts in a list
- How to solve n+1 queries and slow counts with counter caches
- What tools can help you detect n+1 queries
