Date histogram extended bounds date format and key_as_string field format.

[michaelbudnik]

Hello,

My question is why format provided to date histogram is trying to parse min and max extended bounds with the same format? I would like to format the output of the bucket (key_as_string) to show me name of the month ("MMM" format) but I want to provide min and max extended bounds as a simple datetime with format (""yyyy-MM-dd").

Taking the example below:

{
"aggs": {
    "dateHistogram": {
        "date_histogram": {
            "field": "transactions.registryApplication.applicationDate", 
            "interval": "month", 
            "format": "MMM", 
            "min_doc_count": 0, 
            "extended_bounds": {
                "min": "2011-01-01", 
                "max": "2011-12-31"
            }
        }, 
        "aggs": {
            "averagePrice": {
                "avg": {
                    "field": "transactions.sellingPrice"
                }
            }
        }
    }
}
}

I'm getting this error:

[failed to parse date field [2011-01-01], tried both date format [MMM], and timestamp number]

I mean that the format for input (bounds) and output (key_as_string field in response) should be separate, or expect the input date format to be of specific format.

[jpountz]

We don't want to add new options to the date histogram. However, it should be possible to work around this issue by specifying several formats separated by || as documented at https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html

The first format should be used for formatting, and the first format that works should be used for parsing.

Making it an adoptme to make sure this actually works.