Concatenating array objects in elasticsearch transform aggregations

Elastic Stack Elasticsearch
2

I think you can do this easier with a scripted_metric. An advent post from 2 years ago discusses a similar case, unfortunately in german, but just use your favorite online translator:

In short you need something like:

"values": {
  "scripted_metric": {
    "init_script": "state.docs = []",
    "map_script": "state.docs.add(new HashMap(params['_source']['values']))",
    "combine_script": "return state.docs",
    "reduce_script": "def docs = []; for (s in states) {for (d in s) { docs.add(d);}}return docs"
  }
}

You probably need to tweak the map part a bit to e.g. not fail if value is missing in a doc.

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