Unexpected empty inference response – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.6-8.9

Briefly, this error occurs when Elasticsearch’s machine learning feature tries to make a prediction or inference but receives an empty response. This could be due to insufficient data, incorrect data format, or a problem with the inference model. To resolve this, ensure that your data is correctly formatted and sufficient for the model to make predictions. If the problem persists, consider retraining your model with more data or adjusting its parameters. Also, check for any issues with your Elasticsearch cluster that might be causing disruptions in the machine learning feature.

This guide will help you check for common problems that cause the log ” Unexpected empty inference response ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: response, plugin.

Log Context

Log “Unexpected empty inference response” class name is InferenceProcessor.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 }  void mutateDocument(InferModelAction.Response response; IngestDocument ingestDocument) {
 if (response.getInferenceResults().isEmpty()) {
 throw new ElasticsearchStatusException("Unexpected empty inference response"; RestStatus.INTERNAL_SERVER_ERROR);
 assert response.getInferenceResults().size() == 1;


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