elastic/elasticsearch

Dynamic mappings fail when a single document generates inconsistent mapping updates

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#15377 opened on Dec 10, 2015

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 (12 comments) (2 reactions) (0 assignees)Java (76,700 stars) (25,882 forks)batch import
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Description

For instance indexing the following document would fail if the foo.bar field is not mapped explicitly:

{
  "foo": [
    {
      "bar": "baz"
    },
    {
      "bar": 42
    }
  ]
}

The reason is that mapping updates for the 2 sub documents are generated independently (one triggers the creation of a string field and the other one of a long field) but they can't be reconciliated in order to generate the mapping update that will be sent to the master node.

Bug report courtesy of Benjamin Gathmann at https://discuss.elastic.co/t/coerce-long-to-double-not-working/36882.

Contributor guide

Tech stack
java
Domain
backendsearch
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Elasticsearch internalsJava developmentMapping update process
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Investigate the mapping update generation in the DynamicMapping class. The issue occurs when documents with mixed types generate conflicting mapping updates for the same field. The solution likely involves reconciling multiple mapping updates for a single document before sending to the master node. Check relevant code in MapperService and the indexing path. Review comments in the issue for any proposed approaches.