Optimize controllers for large datasets

**Problem**
When working with models, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

Start by locating the controller and model error-handling paths related to large datasets, then reproduce the existing errors to document what information is missing. Done means the affected errors provide more descriptive debugging context and the relevant behavior is verified without changing unrelated error handling.

Written by the indexing model from the issue text.