Training-serving skew occurs when feature transformations or other data seen during training differ from those applied during inference. The mismatch is easy to overlook and can undermine production predictions. Feature stores address it by serving consistently transformed features through offline storage for training or batch inference and online storage for real-time inference. section 1.3.3
Figure 1.7 Feature stores take in transformed data (features) as input and have facilities to store, catalog, and serve features.
Use the feature-store architecture to trace how transformed data becomes cataloged, stored, and served across training and inference paths. section 1.3.3

