[[search-aggregations-bucket]]
== Bucket Aggregations

Bucket aggregations don't calculate metrics over fields like the metrics aggregations do, but instead, they create
buckets of documents. Each bucket is associated with a criterion (depending on the aggregation type) which determines
whether or not a document in the current context "falls" into it. In other words, the buckets effectively define document
sets. In addition to the buckets themselves, the `bucket` aggregations also compute and return the number of documents
that "fell into" each bucket.

Bucket aggregations, as opposed to `metrics` aggregations, can hold sub-aggregations. These sub-aggregations will be
aggregated for the buckets created by their "parent" bucket aggregation.

There are different bucket aggregators, each with a different "bucketing" strategy. Some define a single bucket, some
define fixed number of multiple buckets, and others dynamically create the buckets during the aggregation process.

NOTE: The maximum number of buckets allowed in a single response is limited by a
dynamic cluster setting named
<<search-settings-max-buckets,`search.max_buckets`>>. It defaults to 65,535,
requests that try to return more than the limit will fail with an exception.

include::bucket/adjacency-matrix-aggregation.asciidoc[]

include::bucket/autodatehistogram-aggregation.asciidoc[]

include::bucket/children-aggregation.asciidoc[]

include::bucket/composite-aggregation.asciidoc[]

include::bucket/datehistogram-aggregation.asciidoc[]

include::bucket/daterange-aggregation.asciidoc[]

include::bucket/diversified-sampler-aggregation.asciidoc[]

include::bucket/filter-aggregation.asciidoc[]

include::bucket/filters-aggregation.asciidoc[]

include::bucket/geodistance-aggregation.asciidoc[]

include::bucket/geohashgrid-aggregation.asciidoc[]

include::bucket/geotilegrid-aggregation.asciidoc[]

include::bucket/global-aggregation.asciidoc[]

include::bucket/histogram-aggregation.asciidoc[]

include::bucket/iprange-aggregation.asciidoc[]

include::bucket/missing-aggregation.asciidoc[]

include::bucket/nested-aggregation.asciidoc[]

include::bucket/parent-aggregation.asciidoc[]

include::bucket/range-aggregation.asciidoc[]

include::bucket/rare-terms-aggregation.asciidoc[]

include::bucket/reverse-nested-aggregation.asciidoc[]

include::bucket/sampler-aggregation.asciidoc[]

include::bucket/significantterms-aggregation.asciidoc[]

include::bucket/significanttext-aggregation.asciidoc[]

include::bucket/terms-aggregation.asciidoc[]

include::bucket/variablewidthhistogram-aggregation.asciidoc[]

include::bucket/range-field-note.asciidoc[]