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elasticsearchelasticsearch-painless

Elasticsearch painless script update and get in a one POST call

I am using Elasticsearch 7.4, and have a unique requirement to perform below operation in elasticsearch through painless script:-

  1. Update the field through painless script
  2. Get the updated value in response

#1 I can perform using painless script using below to update the counter value, but how can I get the updated value in response? I want the new value ctx._source.counter in response of the POST call I made, Is there any way?

curl -XPOST -H "Content-Type:application/json" localhost:9200/myindex/_update_by_query -d "{"query":{"bool":{"filter":[{"match":{"field1":"1"}}]}},"script":{"source":"ctx._source.counter = ctx._source.counter + params.incrementValue","lang":"painless","params":{"incrementValue":"2"}}}"

Solution

  • What you want is different from the specs of the _update_by_query API. In the specs you can see the response only contains stats & status of the update, and not the document body (neither initial or final).

    One way to accomplish your goal is:

    1. Query document to update ie. where field1==1
    2. Get initial counter value
    3. Update

    With this, you can get compute the updated value at your end with the method of your choice. In any case it would be two API calls not just one.