Elasticsearch: sorted nested array - elasticsearch

Question

Is it possible to configure the mapping of an index, or the discover view of this in index in a way that an array inside the documents is / will be sorted?
Background: I have a es index with documents containing an array:
This array is updated from time to time with new entries (objects containing a timestamp), and I would like this arrays to be sorted according to the timestamp inside the objects.

Answer 1

If your field is define as nested type then you can use inner_hits to sort the array of object. it will return the sorted object array inside inner_hits for each document.
You can define field as nested like below:
{
"mappings": {
"properties": {
"name": {
"type": "keyword"
},
"openTimes": {
"type": "nested",
"properties": {
"date": {
"type": "date"
},
"name": {
"type": "keyword"
}
}
}
}
}
}
Let consider below is your sample data:
{"index": { } }
{ "name": "second on 6th (3rd on the 5th)", "openTimes": [ { "date": "2018-12-05T12:00:00" ,"name":"abc"}, { "date": "2018-12-06T11:00:00","name":"xyz" }] }
{"index": { } }
{ "name": "third on 6th (1st on the 5th)", "openTimes": [ {"date": "2018-12-05T10:00:00","name":"abc"}, { "date": "2018-12-06T12:00:00","name":"xyz" }] }
{"index": { } }
{ "name": "first on the 6th (2nd on the 5th)", "openTimes": [ {"date": "2018-12-05T11:00:00","name":"abc" }, { "date": "2018-12-06T10:00:00","name":"xyz" }] }
Below is Query:
{
"query": {
"nested": {
"path": "openTimes",
"query": {
"match_all": {}
},
"inner_hits": {
"sort": {
"openTimes.date": "desc"
}
}
}
}
}
Sample Response:
{
"_index" : "nested-listings",
"_type" : "_doc",
"_id" : "u0fw338BMCbs63yKkqi0",
"_score" : 1.0,
"_source" : {
"name" : "second on 6th (3rd on the 5th)",
"openTimes" : [
{
"date" : "2018-12-05T12:00:00",
"name" : "abc"
},
{
"date" : "2018-12-06T11:00:00",
"name" : "xyz"
}
]
},
"inner_hits" : {
"openTimes" : {
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "nested-listings",
"_type" : "_doc",
"_id" : "u0fw338BMCbs63yKkqi0",
"_nested" : {
"field" : "openTimes",
"offset" : 1
},
"_score" : null,
"_source" : {
"date" : "2018-12-06T11:00:00",
"name" : "xyz"
},
"sort" : [
1544094000000
]
},
{
"_index" : "nested-listings",
"_type" : "_doc",
"_id" : "u0fw338BMCbs63yKkqi0",
"_nested" : {
"field" : "openTimes",
"offset" : 0
},
"_score" : null,
"_source" : {
"date" : "2018-12-05T12:00:00",
"name" : "abc"
},
"sort" : [
1544011200000
]
}
]
}
}
}
}