This replaces the `script` docs for bucket aggregations with runtime
fields. We expect runtime fields to be nicer to work with because you
can also fetch them or filter on them. We expect them to be faster
because their don't need this sort of `instanceof` tree:
a92a647b9f/server/src/main/java/org/elasticsearch/search/aggregations/support/values/ScriptDoubleValues.java (L42)
Relates to #69291
Co-authored-by: James Rodewig <40268737+jrodewig@users.noreply.github.com>
Co-authored-by: Adam Locke <adam.locke@elastic.co>
Adds a new single-value metrics aggregation that computes the weighted
average of numeric values that are extracted from the aggregated
documents. These values can be extracted from specific numeric
fields in the documents.
When calculating a regular average, each datapoint has an equal "weight"; it
contributes equally to the final value. In contrast, weighted averages
scale each datapoint differently. The amount that each datapoint contributes
to the final value is extracted from the document, or provided by a script.
As a formula, a weighted average is the `∑(value * weight) / ∑(weight)`
A regular average can be thought of as a weighted average where every value has
an implicit weight of `1`.
Closes#15731
Nik Everett
James Rodewig
James Rodewig
Mark Tozzi
Zachary Tong