Max bucket aggregation

Max bucket aggregation #

A sibling pipeline aggregation identifying the largest per-bucket metric value — e.g. the best-performing group. Bucket aggregations can sort their own output, but only inside one request’s bucket list; max_bucket lifts the winning number out as a single headline metric next to the breakdown.

"best_seller": { "max_bucket": { "buckets_path": "per_type>revenue" } }

How it works #

max_bucket is declared next to the bucket aggregation it consumes and runs after every regular aggregation — including the distributed merge — has finished. It walks the parent’s finished buckets, collects one number per bucket, and returns their maximum as a single-value metric ({"value": 1800}) placed alongside the parent. Only the value is returned — not which bucket produced it; read the parent’s bucket list (or sort it with bucket_sort) when you need the winner’s key.