EF Core's Change Tracking: The Sneaky Default That Fixes Your Perf, Then Ghosts Your Updates With Duplicate Key Nightmares

Entity Framework Core's default change tracking feature can lead to unexpected bugs and performance issues if not properly understood and managed. Developers often enable or disable tracking globally, resulting in memory spikes, SQL log explosions, and random primary key violations. Disabling tracking can improve performance but may cause relationship updates to fail with duplicate key exceptions. EF Core's change tracking keeps an internal graph of entities, maintaining their state and relationships, but disabling tracking means EF does not track entities, leading to silent failures and incorrect updates. To resolve these issues, developers can split repositories into read and write operations, using AsNoTracking for read-heavy endpoints and tracking for commands that require state awareness and relationship handling. This approach eliminates accidental tracking, prevents silent no-ops, and makes performance predictable, allowing developers to design their data access layer with intent and precision, ultimately leading to more efficient and reliable database interactions.