Question

I have a field field10 which got created by accident when I updated a particular record in my index. I want to remove this field from my index, all its contents and recreate it with the below mapping:

"mytype":{
  "properties":{
    "field10":{ 
      "type":"string",
      "index":"not_analyzed",
      "include_in_all":"false",
      "null_value":"null"      
    }  
  }  
}

When I try to create this mapping using the Put Mapping API, I get an error: {"error":"MergeMappingException[Merge failed with failures {[mapper [field10] has different index values, mapper [field10] has different index_analyzer, mapper [field10] has different search_analyzer]}]","status":400}.

How do I change the mapping of this field? I don’t want to reindex millions of records just for this small accident.

Thanks

Answer 1

AFAIK, you can’t remove a single field and recreate it.
You can not either just modify a mapping and have everything reindexed automagicaly. Imagine that you don’t store _source. How can Elasticsearch know what your data look like before it was indexed?

But, you can probably modify your mapping using a multifield with field10.field10 using the old mapping and field10.new with the new analyzer.

If you don’t reindex, only new documents will have content in field10.new.
If you want to manage old documents, you have to:

• Send again all your docs (it will update everything) – aka reindex (you can use scan & scroll API to get your old documents)
• Try to update your docs with the Update API

You can probably try to run a query like:

curl -XPOST localhost:9200/crunchbase/person/1/_update -d '{
    "script" : "ctx._source.field10 = ctx._source.field10"
}'

But, as you can see, you have to run it document by document and I think it will take more time than reindexing all with the Bulk API.

Does it help?