Not this again. ORMs are tools, basically dynamic code generators that run SQL and map the results to in-memory objects, and vice-versa. Some are simplistic and others are incredibly advanced, and the code itself is usually faster than your own sql->objects logic that you would write otherwise.
The issues with performance are almost always with the way the tool is used, like choosing a bad algorithms or the wrong data structure for a certain situation.
Lazy-loading a large child object in a tight loop over 100s of entries will always be slow because it's an improper approach, and nothing other than knowledge and competency will resolve that. It's rather amazing ORMs can be so controversial when the real issue is the developer, which speaks to the far bigger problem of expertise and quality in this industry.
The issues with performance are almost always with the way the tool is used, like choosing a bad algorithms or the wrong data structure for a certain situation.
Lazy-loading a large child object in a tight loop over 100s of entries will always be slow because it's an improper approach, and nothing other than knowledge and competency will resolve that. It's rather amazing ORMs can be so controversial when the real issue is the developer, which speaks to the far bigger problem of expertise and quality in this industry.