Learn how to use SQL subqueries in Ruby on Rails to eliminate N+1 queries without eager loading, reduce memory usage, and improve performance.

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Learn how to address the N+1 query problem in Rails without resorting to eager loading. By leveraging SQL subqueries, you can fetch specific associated records directly within your main query, reducing memory consumption and improving performance. The post walks through a real-world example of fetching a member's latest activity timestamp efficiently, discussing various approaches and their trade-offs before demonstrating the optimal SQL subquery solution.

Fix N+1 Queries Without Eager Loading Using SQL Subquery

The Simplest Solution that Works: But at a Cost

Attempt 1: Eager Loading - Better Queries, Worse Memory

<p>Not a ruby on rail guy so couldn’t get a lot, but liked the thoughtful consideration to the problem and going beyond the response time to check cpu and memory overload. kudos.</p>
