👀 Views: 1112 💬 Answers: 1 📅 Created: 2025-06-11

ruby rails activerecord postgresql Ruby

I'm deploying to production and I'm working on a personal project and I'm working with an scenario where my Rails 7.1 application is consuming an unexpectedly high amount of memory when executing queries with ActiveRecord on a PostgreSQL database. The question seems to occur primarily when I'm loading associations with large datasets. I have a `Post` model that has many `Comments`, and I want to load posts along with their associated comments. However, the memory usage spikes significantly when I use `includes` versus just `eager_load`. Here’s a simplified version of my code: ```ruby class PostsController < ApplicationController def index @posts = Post.includes(:comments).all end end ``` When I run this query, I noticed that the memory usage jumps from around 200MB to over 1GB. I also tried using `eager_load` instead, but that didn't seem to resolve the question either. I monitored the memory with the `memory_profiler` gem and found that the bulk loading of comments is causing most of the overhead. I have around 10,000 posts, and each post can have several hundred comments. My database is indexed appropriately, and I'm using PostgreSQL version 14. I also tried limiting the number of comments loaded with a `where` clause and pagination, but the scenario continues. Is there a more efficient way to load these associations without running into memory issues? Any best practices for handling large datasets with ActiveRecord would be greatly appreciated. The stack includes Ruby and several other technologies.