No type specified for field ” + fieldName + ” – How to solve this Elasticsearch error

No type specified for field ” + fieldName + ” – How to solve this Elasticsearch error

Opster Team

February-21, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run the Elasticsearch Error Check-Up. It will help you detect configuration issues prior to errors appearing that harm your system’s performance.

This guide will help you check for common problems that cause the log “No type specified for field ” + fieldName + “” 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: index.

Background

Fields and mapping types in Elasticsearch do not need to be defined before being used if you are using dynamic mapping (in dynamic mapping, based on the field value, Elasticsearch determines the data-type). However, when you are creating a new index with an explicit mapping, you need to define what kind of data the field contains. You cannot just add the field name without mentioning the field data type in the index mapping. It is necessary to add the field data type if you are including the field name in the index mapping. 

The below exception arises if you do not specify the field data type for the field name included in the index mapping. You will not be able to add index mapping in Elasticsearch.

How to reproduce this exception

To recreate this exception, create an index with this mapping:

Index Mapping

PUT /my-index
{
 "mappings": {
   "properties": {
     "user": {
     }
   }
 }
}

Response 

{
 "error": {
   "root_cause": [
     {
       "type": "mapper_parsing_exception",
       "reason": "No type specified for field [user]"
     }
   ],
   "type": "mapper_parsing_exception",
   "reason": "Failed to parse mapping [_doc]: No type specified for field [user]",
   "caused_by": {
     "type": "mapper_parsing_exception",
     "reason": "No type specified for field [user]"
   }
 },
 "status": 400
}

How to fix this exception

Mapping defines the property of each field in the index. These properties may contain the data type of each field and how fields are going to be tokenized and indexed. Refer to this Elasticsearch official documentation on field data type for more information.

Here is an option for the modified index mapping (you can change the field data type according to your use case):

Modify the index mapping

PUT /my-index
{
 "mappings": {
   "properties": {
     "user": {
       "type":"text"
     }
   }
 }
}

 

Log Context

Log”No type specified for field [” + fieldName + “]”classname  is ObjectMapper.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

// flag on it; make it an object
  // (usually; setting enabled to false to not index
  // any type; including core values; which
  type = ObjectMapper.CONTENT_TYPE;
  } else {
  throw new MapperParsingException("No type specified for field [" + fieldName + "]");
  }
  }
 
  Mapper.TypeParser typeParser = parserContext.typeParser(type);
  if (typeParser == null) {

 

Run the Check-Up to get a customized report like this:

Analyze your cluster