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Error Logs

Error Log: mapper_parsing_exception – The “wrong data type” error

By November 19, 2025No Comments

Error Log: This error happens during indexing (writing a document) and is a very common part of a bulk request failure:

{
  "error" : {
    "root_cause" : [
      {
        "type" : "mapper_parsing_exception",
        "reason" : "failed to parse field [http_response_code] of type [long] in document with id '...'. 
                    Preview of field's value: 'N/A'"
      }
    ],
    "type" : "mapper_parsing_exception",
    "reason" : "failed to parse field [http_response_code]...",
    "caused_by" : {
      "type" : "number_format_exception",
      "reason" : "For input string: \"N/A\""
    }
  },
  "status" : 400
}

Why… is this happening? A MapperParsingException means you are sending data that does not match the schema (called the “mapping”) for your index.

In the example above:

  1. The index mapping defines the field http_response_code as a long (a number).
  2. The application tried to send a document where http_response_code had the value "N/A" (a string).
  3. OpenSearch cannot store the text string "N/A" in a field that is only for numbers, so it rejects the document and throws this error.

This is the most common data-quality issue new users face.

Best Practice:

  1. Check Your Mapping: First, understand what OpenSearch expects. Use GET /my-index-name/_mapping to see the data type (long, keyword, text, boolean, etc.) for the field in question.
  2. Clean Your Data (Best Solution): The best fix is to “clean” the data at the source. Your application (e.g., Logstash, Filebeat, or your custom code) should standardize this data before sending it to OpenSearch. For example, change "N/A" to null or a specific number like 0.
  3. Fix Your Mapping (If Necessary): If you must store both numbers and strings in the same field, you must re-index. Create a new index where that field is mapped as keyword (for exact strings) or text (for full-text search). You cannot change the mapping of an existing field.

What else can I do? Unsure how to clean your data or how to re-index with a new mapping? Ask the OpenSearch community! Show them your data sample and your mapping, and they can provide the best path forward. For detailed help, reach out to the vibrant OpenSearch community for help and support on the OpenSearch Slack Channel.

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