Extended stats aggregation
/ Extended_stats, / AggregationExtended stats aggregation #
A multi-value metrics aggregation extending
stats with
squares, variance, standard deviation and their lower/upper bounds. Where
stats says what the values are, extended_stats says how tightly they
cluster around the mean — the input for outlier bands, quality gates and
anything else built on “how unusual is this value”.
How it works #
The engine walks the matching documents once, maintaining a running count,
sum, sum_of_squares, minimum and maximum — the same single pass as
stats, plus one multiply-add for the squares. Everything downstream is
derived from these raw moments, and is exact (no sampling, no sketches):