Inference is a machine learning feature that enables you to use supervised machine learning processes – like Regression or Classification – not only as a batch analysis but in a continuous fashion. This means that inference makes it possible to use trained machine learning models against incoming data.

For instance, suppose you have an online service and you would like to predict whether a customer is likely to churn. You have an index with historical data – information on the customer behavior throughout the years in your business – and a classification model that is trained on this data. The new information comes into a destination index of a continuous transform. With inference, you can perform the classification analysis against the new data with the same input fields that you’ve trained the model on, and get a prediction.

Let’s take a closer look at the machinery behind inference.

Inference processoredit

Inference can be used as a processor specified in an ingest pipeline. It uses a trained model to infer against the data that is being ingested in the pipeline. The model is used on the ingest node. Inference pre-processes the data by using the model and provides a prediction. After the process, the pipeline continues executing (if there is any other processor in the pipeline), finally the new data together with the results are indexed into the destination index.

Check the inference processor and the machine learning data frame analytics API documentation to learn more about the feature.

Inference aggregationedit

Inference can also be used as a pipeline aggregation. You can reference a trained model in the aggregation to infer on the result field of the parent bucket aggregation. The inference aggregation uses the model on the results to provide a prediction. This aggregation enables you to run classification or regression analysis at search time. If you want to perform the analysis on a small set of data, this aggregation enables you to generate predictions without the need to set up a processor in the ingest pipeline.

Check the inference bucket aggregation and the machine learning data frame analytics API documentation to learn more about the feature.

If you use trained model aliases to reference your trained model in an inference processor or inference aggregation, you can replace your trained model with a new one without the need of updating the processor or the aggregation. Reassign the alias you used to a new trained model ID by using the Create or update trained model aliases API. The new trained model needs to use the same type of data frame analytics as the old one.