# Push vs Pull Model

## Push vs Pull Model

Feast uses a [Push Model](https://en.wikipedia.org/wiki/Push_technology), i.e., Data Producers push data to the feature store and Feast stores the feature values in the online store, to serve features in real-time.

In a [Pull Model](https://en.wikipedia.org/wiki/Pull_technology), Feast would pull data from the data producers at request time and store the feature values in the online store before serving them (storing them would actually be unnecessary). This approach would incur additional network latency as Feast would need to orchestrate a request to each data producer, which would mean the latency would be at least as long as your slowest call. So, in order to serve features as fast as possible, we push data to Feast and store the feature values in the online store.

The trade-off with the Push Model is that strong consistency is not guaranteed out of the box. Instead, strong consistency has to be explicitly designed for in orchestrating the updates to Feast and the client usage.

The significant advantage with this approach is that Feast is read-optimized for low-latency feature retrieval.

## How to Push

Implicit in the Push model are decisions about *how* and *when* to push feature values to the online store.

From a developer's perspective, there are three ways to push feature values to the online store with different tradeoffs.

They are discussed further in the [Write Patterns](https://github.com/feast-dev/feast/blob/v0.42-branch/docs/getting-started/architecture/getting-started/architecture/write-patterns.md) section.


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