ActiveRecord Query Performance Degradation with Large Dataset in Ruby on Rails 7
I'm prototyping a solution and I'm relatively new to this, so bear with me..... I tried several approaches but none seem to work. I can't seem to get I'm testing a new approach and Hey everyone, I'm running into an issue that's driving me crazy... I'm experiencing significant performance issues when querying a large dataset using ActiveRecord in my Rails 7 application. I have a `User` model with about 1 million records, and when I run the following query to fetch users based on specific conditions, it takes a long time to respond: ```ruby User.where(active: true).order('created_at DESC').limit(100) ``` While testing this, I noticed that the SQL generated is causing full table scans instead of using an index, leading to a performance bottleneck. The database schema includes an index on the `active` column, but it seems that the `order` clause is disregarding it. I have tried adding a composite index on both `active` and `created_at`: ```ruby add_index :users, [:active, :created_at] ``` However, this hasn't resolved the issue, and the query performance remains poor. I also attempted to use `pluck` to reduce memory usage: ```ruby User.where(active: true).order('created_at DESC').limit(100).pluck(:id) ``` But that hasn’t made a noticeable difference either. When I check the query execution plan using `EXPLAIN`, it shows that the index is not being utilized effectively. I’ve also considered whether there are any N+1 query issues in parts of my application that might be slowing things down, but using `includes` hasn’t yielded the results I hoped for. Is there a better way to optimize my ActiveRecord queries for large datasets in Rails 7? Any suggestions for indexing strategies or query optimizations that can help improve performance would be greatly appreciated. Is there a better approach? My development environment is Windows 10. What are your experiences with this? My development environment is Windows 10. Is there a better approach? This is for a CLI tool running on Debian. Am I approaching this the right way? I'm working on a mobile app that needs to handle this. This is my first time working with Ruby stable. Any advice would be much appreciated.