How can I optimize my Rails database queries?

How can I optimize my Rails database queries?

To optimize your Rails database queries, consider using eager loading to reduce N+1 queries, indexing your database columns, and using the select method to retrieve only the necessary fields.

What is eager loading and how does it help?

Eager loading is a way to load associated records in a single query instead of multiple queries. It helps reduce the number of database calls, improving performance.

Can you give me an example of using eager loading?

Sure! Instead of using Post.all which may trigger N+1 queries, you can use Post.includes(:comments).all to load posts along with their comments in one query.

What are some common mistakes to avoid when querying in Rails?

Common mistakes include not using indexes, forgetting to use select for specific fields, and not utilizing caching effectively.