Meta values can only be strings; but got – 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.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

This guide will help you check for common problems that cause the log ” meta values can only be strings; but got ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Log Context

Log “[meta] values can only be strings; but got”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

"] for field [" + name + "]");
 } else if (value == null) {
 throw new MapperParsingException("[meta] values can't be null (field [" + name + "])");
 } else {
 throw new MapperParsingException("[meta] values can only be strings; but got " +
 value.getClass().getSimpleName() + "[" + value + "] for field [" + name + "]");
 final Function; Object> entryValueFunction = Map.Entry::getValue;
 final Function stringCast = String.class::cast;


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