Expected map for property fields on field ” + fieldName + ” but got a – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many configuration errors.

Briefly, this error occurs when Elasticsearch is unable to process the mapping configuration for an index due to an unexpected data type. Elasticsearch expects a map for the fields property on a field but received a different data type. To resolve the issue, review and correct the mapping configuration.

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This guide will help you check for common problems that cause the log ” Expected map for property fields on field ” + fieldName + ” but got a ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Log Context

Log “Expected map for property [fields] on field [” + fieldName + “] but got a”classname  is ObjectMapper.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

DocumentMapperParser.checkNoRemainingFields(fieldName; propNode; parserContext.indexVersionCreated());
 } else if (isEmptyList) {
 } else {
 throw new MapperParsingException("Expected map for property [fields] on field [" + fieldName + "] but got a "
 + fieldName.getClass());
 DocumentMapperParser.checkNoRemainingFields(propsNode; parserContext.indexVersionCreated();


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