Meta values can only be strings but got – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.6-7.15

Briefly, this error occurs when non-string values are passed in the [meta] field in Elasticsearch. The [meta] field only accepts string values. To resolve this issue, ensure that all values passed in the [meta] field are string values. If the values are numeric or boolean, convert them to string before passing them to the [meta] field. Also, check your data input or ingestion scripts to ensure they are not mistakenly passing non-string values to the [meta] field.

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” class name 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 + "]");
 Map sortedMeta = new TreeMap<>();
 for (Map.Entry entry : meta.entrySet()) {


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