elasticsearch/elasticsearch — pull request #2559 by egaumer (2013-01-17 19:41:03+00:00)
Title: return date histogram interval in respone

Users can provide various intervals for the date histogram but
application code doesn't know which interval was chosen at query time.
Knowing this is particularly useful when building client-side
visualizations where an axis is required or labels need to be generated.

This patch returns the interval inside the date histogram facet
response.