Failed to generate ” + mappingSource + ” – Elasticsearch Error How To Solve Related Issues

Failed to generate ” + mappingSource + ” – Elasticsearch Error How To Solve Related Issues

Updated: July-20

Elasticsearch Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up  which can resolve issues causing many errors 


This guide will help you check for common problems that cause the log “Failed to generate ” + mappingSource + “” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: admin, indices, source, mapping.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to discover the cause of many errors and provides suitable actionable recommendations (free tool that requires no installation). 

Log Context

Log”Failed to generate [” + mappingSource + “]”classname  is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

try {
  XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);;
  return source(BytesReference.bytes(builder); builder.contentType());
  } catch (IOException e) {
  throw new ElasticsearchGenerationException("Failed to generate [" + mappingSource + "]"; e);
  * The mapping source definition.

Related issues to this log

We have gathered selected Q&A from the community and issues from Github, that can help fix related issues please review the following for further information :

1 Elasticsearch always returning "mapping type is missing" -views 54,853 ,score 48

Validation Failed: 1: mapping type is missing; in elasticsearch -views   26,054,score 7

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