Question

Elasticsearch Histogramfacet doesn’t appear to support all_terms = true (i.e: return facetvalue / bucket even though count=0)

Is this correct?

Answer 1

Yes, this is correct. However, if you are not using relevancy to sort your results you can move your query into the top-level filter element and put match_all into the top-level query element. For example, for following request will return two histograms – one only with elements that correspond to the query and another one for entire index:

{
    "query": {
        "match_all": {}
    },
    "filter": {
        // filter goes here
    },
    "facets": {
        "histo_all": {
            "histogram": {
                "field": "my_field"
            }
        },
        "histo": {
            "histogram": {
                "field": "my_field"
            },
            "facet_filter": {
                // same filter from top-level filter goes here
            }
        }
    }
}