elasticsearch/docs/reference/migration/migrate_5_0/aggregations.asciidoc

[[breaking_50_aggregations_changes]]
=== Aggregation changes

==== Significant terms on numeric fields

Numeric fields have been refactored to use a different data structure that
performs better for range queries. However, since this data structure does
not record document frequencies, numeric fields can no longer be used for
significant terms aggregations. It is recommended to use <<keyword,`keyword`>>
fields instead, either directly or through a <<multi-fields,multi-field>>
if the numeric representation is still needed for sorting, range queries or
numeric aggregations like
<<search-aggregations-metrics-stats-aggregation,`stats` aggregations>>.