Virtual columns for expressions is a feature of the columnar engine in

## Feature Feature [Virtual columns for expressions](https://cloud.google.com/alloydb/docs/columnar-engine/add-frequent-expressions)is a feature of the columnar engine in[Preview](https://cloud.google.com/products#product-launch-stages) that significantly improves query performance and reduces CPU consumption. It caches the results of frequently used expressions, which is especially beneficial for analytical workloads on large datasets.