What does schema validation detect?

Schema validation is a critical process in which the structure of a database is checked against a predefined schema to ensure that the data conforms to the specified format, constraints, and requirements. This helps to maintain data integrity and prevents errors within the database environment.

The correct answer highlights that schema validation detects differences between the database configuration and the schema. This means it checks for discrepancies like missing fields, incorrect data types, or violations of constraints that have been defined in the schema. Ensuring that the database structure aligns with the schema is vital for the smooth functioning of applications, as any inconsistencies could lead to runtime errors or data corruption.

While other options touch on important aspects of data management or security, they do not pertain to the primary function of schema validation. For example, incorrect user login attempts relate to authentication processes, performance metrics pertain to system monitoring and optimization, and data redundancy involves the duplication of data rather than issues with database structure or schema alignment.