Unknown value v for field – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.1-7.15

Briefly, this error occurs when Elasticsearch encounters an unexpected value for a specific field during indexing or querying. This could be due to a mismatch in data types or a value outside the expected range. To resolve this, ensure that the data type of the value matches the mapping of the field. If the field expects a range of values, make sure the input falls within this range. Also, check for any typos or incorrect field names in your query. Lastly, consider updating your mapping if the current one doesn’t suit your data needs.

This guide will help you check for common problems that cause the log ” Unknown value [” + v + “] for field [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Log Context

Log “Unknown value [” + v + “] for field [” class name is FieldMapper.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 return stringParam(name; updateable; initializer; values[0])
 .setValidator(v -> {
 if (acceptedValues.contains(v)) {
 throw new MapperParsingException("Unknown value [" + v + "] for field [" + name +
 "] - accepted values are " + acceptedValues.toString());
 }  /**