Elasticsearch aggregation using top_hits field with script ordering - database

Question

I have a set of documents with src, txt and flt fields. I want to query by txt field in the following way:
Group (bucketize) by src;
In each bucket calculate top 1 most relevant document;
Order each bucket by the _score * doc.flt value.
So far I have implemented 1 and 2, but not 3. Even if 3 may be not very efficient, I still want to have such an option. My query looks like:
{
"query" : {
'match' : {
'text' : {
'query' : <some text>,
'fuzziness' : 'AUTO',
'operator' : 'and'
}
}
},
"aggs": {
"by_src": {
"terms": {
"field": "src",
"size" : 10,
"order" : {"top_score" : "desc"}
},
"aggs": {
"top_hits" : {
"top_hits" : {
"sort": { "_score": { "order": "desc" } },
"size" : 1
}
},
"top_score": {
"max" : {
"script" : "_score",
}
}
}
}
}
}

Answer 1

I believe it's failing because you don't need to use _source field to apply the sort to each bucket, just apply the sort by the field name:
{
"query" : {
'match' : {
'text' : {
'query' : <some text>,
'fuzziness' : 'AUTO',
'operator' : 'and'
}
}
},
"aggs": {
"by_src": {
"terms": {
"field": "src",
"size" : 10,
"order" : {"top_score" : "desc"}
},
"aggs": {
"top_hits" : {
"top_hits" : {
"sort":[{
"flt": {"order": "desc"}
}],
"size" : 1
}
},
"top_score": {
"max" : {
"script" : "_score",
}
}
}
}
}
}
I am assuming your document has a field called flt that you want to use to sort. Naturally you can also change the sorting to asc if it's what you need.