Why Does Using an ORM Decrease Database Performance? An Experience...

Why Does Using an ORM Decrease Database Performance? While trying to optimize the shipping module in a production ERP, I noticed that database queries were incredibly slow. At first, I examined the SQL queries and checked the indexes. However, I couldn't get the performance boost I expected. The problem lay in the Object-Relational Mapper (ORM) library, which was the cornerstone of our application. ORMs make things easier for software developers by providing an abstract layer for database operations, but this convenience often comes at a performance cost. In this post, I will explain why using an ORM decreases database performance, using concrete examples from my own field experience. The core promise of ORMs is to keep developers away from SQL and allow them to interact with databases in a way that is more aligned with the object-oriented paradigm. This is a huge advantage, especially in small and medium-sized projects or rapid prototyping processes. However, when things get complex and performance becomes critical, the efficiency of the queries generated by ORMs starts to be questioned. In many cases I have encountered, especially in enterprise software development processes, the default behaviors of ORMs created an unexpected load on database servers. Query Inefficiencies Generated by ORMs ORMs usually manage database relationships using mechanisms like "eager loading" or "lazy loading". Depending on the developer's preference, these mechanisms either fetch all related data at once (eager loading) or fetch it in pieces as needed (lazy loading). However, ORMs may not always perform these loads in the most optimized way. For example, while only a few fields like ID and name are sufficient in a list view, the ORM might query the entire table or all related tables. This situation causes unnecessary data transfer and unnecessarily overloads the database server. To give an example, on the order list screen of an e-commerce site, we needed to display the customer inform