Optimizing ActiveRecord Queries with Complex Joins in Rails 7.1 for Performance Issues
I've been researching this but After trying multiple solutions online, I still can't figure this out. During development, I’ve run into some serious performance bottlenecks in a Ruby on Rails 7.1 application that relies heavily on complex database queries. Specifically, I’m working with a model that performs multiple joins with large tables, leading to slow response times when fetching data. The main culprit seems to be related to how ActiveRecord constructs these queries. I've tried using the `includes` method to eager load associations and avoid N+1 queries, but it hasn’t yielded the expected results. For instance, here’s a simplified version of what I’m currently using: ```ruby # This is the initial attempt using includes @users = User.includes(:posts, :comments).where(active: true) ``` Despite this, the performance is still subpar. After profiling the application, I've noticed that the SQL generated is pulling in too much data unnecessarily. To mitigate this, I switched to using `select` to limit the fields returned: ```ruby # Attempting to limit fields with select @users = User.select(:id, :name).joins(:posts).where(active: true) ``` However, this still doesn’t address the underlying performance issue. I want to explore using raw SQL for more control over the query. Here’s an example of what I’m considering: ```ruby # Experimenting with raw SQL for better control @users = User.find_by_sql("SELECT u.id, u.name FROM users u JOIN posts p ON u.id = p.user_id WHERE u.active = true") ``` While this approach seems promising, it sacrifices some of ActiveRecord's features, such as automatic model instantiation. I’m also concerned about maintainability and readability. Has anyone faced similar issues with ActiveRecord and large complex joins? Are there best practices or alternative approaches you’ve found effective? I’ve also read that using database indexes strategically can help, but I’m unsure about which fields to index. Any guidance on balancing performance and maintainability would be appreciated! My development environment is macOS. Is there a better approach? Has anyone else encountered this? Thanks for any help you can provide!