Rare terms aggregation #

A multi-bucket aggregation that keeps only RARE terms — bucket keys whose document count is at or below max_doc_count. The mirror image of terms for finding the long tail.

Example #

Every product type sells ≥10 times; raise the bar to 15 and only sticker (10 sales) survives:

Parameters for rare_terms #

• field
  (Required, string) Keyword field you wish to aggregate.
• max_doc_count
  (Optional, integer, default: 1) Maximum document count for a term to be considered rare.
• include / exclude
  (Optional) Restrict candidate terms (exact values or wildcard patterns).