No type specified for field fieldName – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when a field in an Elasticsearch index is defined without specifying its type. Elasticsearch needs to know the type of each field for proper indexing and searching. To resolve this issue, you can either specify the type of the field in the mapping when creating the index or update the mapping of an existing index to include the type. If the field type is unknown, you can use the ‘dynamic’ option to let Elasticsearch automatically detect the field type.

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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 + “]” class name 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 + "]");
 }
 }  if (objBuilder.subobjects.value() == false && type.equals(ObjectMapper.CONTENT_TYPE)) {
 throw new MapperParsingException(

 

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