Meta keys can’t be longer than 20 chars; 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 Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” meta keys can’t be longer than 20 chars; but got ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “[meta] keys can’t be longer than 20 chars; but got [“classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

throw new MapperParsingException("[meta] can't have more than 5 entries; but got " + meta.size() + " on field [" +
 name + "]");
 for (String key : meta.keySet()) {
 if (key.codePointCount(0; key.length()) > 20) {
 throw new MapperParsingException("[meta] keys can't be longer than 20 chars; but got [" + key +
 "] for field [" + name + "]");
 for (Object value : meta.values()) {
 if (value instanceof String) {


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