Failed to parse mapping for type – How to solve this Elasticsearch error

Overview

You can create a mapping of an index using the _mappings REST endpoint. The very first time Elasticsearch finds a new field whose mapping is not pre-defined inside the index, it automatically tries to guess the data type and analyzer of that field and set its default value. For example, if you index an integer field without pre-defining the mapping, Elasticsearch sets the mapping of that field as long.

Examples

Create an index with predefined mapping:

PUT /my_index?pretty
{
  "settings": {
    "number_of_shards": 1
  },
  "mappings": {
    "properties": {
      "name": {
        "type": "text"
      },
      "age": {
        "type": "integer"
      }
    }
  }
}

Create mapping in an existing index:

PUT /my_index/_mapping?pretty
{
  "properties": {
    "email": {
      "type": "keyword"
    }
  }
}

View the mapping of an existing index:

GET my_index/_mapping?pretty

View the mapping of an existing field:

GET /my_index/_mapping/field/name?pretty

Notes

• It is not possible to update the mapping of an existing field. If the mapping is set to the wrong type, re-creating the index with updated mapping and re-indexing is the only option available.
• In version 7.0, Elasticsearch has deprecated the document type and the default document type is set to _doc. In future versions of Elasticsearch, the document type will be removed completely.

How to optimize your Elasticsearch mapping to reduce costs

Watch the video below to learn how to save money on your deployment by optimizing your mapping.

Common problems

• The most common problem in Elasticsearch is incorrectly defined mapping which limits the functionality of the field. For example, if the data type of a string field is set as text, you cannot use that field for aggregations, sorting or exact match filters. Similarly, if a string field is dynamically indexed without predefined mapping, Elasticsearch automatically creates two fields internally. One as a text type for full-text search and another as keyword type, which in most cases is a waste of space. 
• Elasticsearch automatically creates an _all field inside the mapping and copies values of each field of a document inside the _all field. This field is used to search text without specifying a field name. Make sure to disable the _all field in production environments to avoid wasting space. Please note that support for the _all field has been removed in version 7.0.
• In versions lower than 5.0, it was possible to create multiple document types inside an index, similar to creating multiple tables inside a database. In those versions, there were higher chances of getting data types conflicts across different document types if they contained the same field name with different data types. 
• The mapping of each index is part of the cluster state and is managed by master nodes. If the mapping is too big, meaning there are thousands of fields in the index, the cluster state grows too large to be handled and creates the issue of mapping explosion, resulting in the slowness of the cluster.

Overview

Deprecation refers to processes and functions that are in the process of being eliminated and (possibly) replaced by newer ones.

Typically, a function will not disappear from one version to the next without warning. Normally this will happen across a number of versions. When you use a deprecated function in intermediate versions, it will continue to work as before, but you will receive warnings that the function in question is intended to disappear in the future.

How it works

There are a number of ways you can find out which functions have been deprecated, including: deprecation logs, reading the breaking pages documentation and paying attention to warnings.

In a deprecation log:

{"type": "deprecation", "timestamp": "2020-01-16T12:50:11,263+0000", "level": "WARN", "component": "o.e.d.r.a.d.RestDeleteAction", "cluster.name": "docker-cluster", "node.name": "es01", "cluster.uuid": "VGTYFgunQ_STTKVz6YHAGg", "node.id": "wh5J7TJ-RD-pJE4JOUjVpw",  "message": "[types removal] Specifying types in document index requests is deprecated, use the typeless endpoints instead (/{index}/_doc/{id}, /{index}/_doc, or /{index}/_create/{id})."  }

Reading the breaking changes documentation for each version:

https://www.elastic.co/guide/en/elasticsearch/reference/7.5/breaking-changes-7.0.html

In kibana you may also see a warning if you run a deprecated command in the development panel:

#! Deprecation: [types removal] Specifying types in document index requests is deprecated, use the typeless endpoints instead (/{index}/_doc/{id}, /{index}/_doc, or /{index}/_create/{id}).

It is important to act upon these warnings. Although your application still works, ignoring the warnings will almost certainly cause things to malfunction in a future upgrade.

Deprecation API

There is a depreciation API, which can help point you to deprecated functions on your cluster:

However, you should never depend on the deprecation API alone. Just because the API returns with no issues, it does not mean that everything in your setup will work out of the box when migrating!  This is to be used in addition to looking through the deprecation log and breaking changes documentation.

Examples

• The removal of document types (“_type”) . Various document types were allowed in a single index in version 6, but this functionality has been removed. You will get warnings if you use document types in queries, and only 1 document type is allowed per index in version 7.  The functionality is expected to be completely removed in version 8.
• The discovery.zen.minimum_master_nodes setting is permitted, but ignored, on 7.x nodes.

There are many more examples to be found in the breaking changes documentation.

Notes and good things to know

It is important to visit ALL the breaking changes for each minor version between the version you are using and the version you want to upgrade to.

https://www.elastic.co/guide/en/elasticsearch/reference/7.3/breaking-changes-7.3.html

Contains information that is not mentioned on the next page.

https://www.elastic.co/guide/en/elasticsearch/reference/7.5/breaking-changes-7.4.html

The best way is to go to the “breaking changes” page of the version you want to upgrade to, and then use the links to page look through all of the minor version pages down to the one you want to upgrade from, paying particular attention to the major version change (eg. 7.0 )

Opster supports all Elasticsearch versions so If you need help reach out