elasticsearch/docs/reference/scripting-languages/painless/painless-metric-agg-combine-context.md

mapped_pages	products
https://www.elastic.co/guide/en/elasticsearch/painless/current/painless-metric-agg-combine-context.html	id painless

Metric aggregation combine context [painless-metric-agg-combine-context]

Use a Painless script to combine values for use in a scripted metric aggregation. A combine script is run once per shard following a map script and is optional as part of a full metric aggregation.

Variables

params (Map, read-only)

User-defined parameters passed in as part of the query.

state (Map)

Map with values available from the prior map script.

Return

List, Map, String, or primitive

A value collected for use in a reduce script. If no reduce script is specified, the value is used as part of the result.

API

The standard Painless API is available.