Bucket aggregations compute bucket doc_count values by incrementing the doc_count by 1 for every document collected in the bucket.
When using summary fields (such as aggregate_metric_double) one field may represent more than one document. To provide this functionality we have implemented a new field mapper (named doc_count field mapper). This field is a positive integer representing the number of documents aggregated in a single summary field.
Bucket aggregations will check if a field of type doc_count exists in a document and will take this value into consideration when computing doc counts.
