How to speed up document append to existing array in elasticsearch? - elasticsearch

Question

I am using elasticsearch version 6.3.1.
And I am creating a nested type field,I have created this field to append all the documents of same ID.
Here is my schema for index:-
curl -XPUT 'localhost:9200/axes_index_test12?pretty' -H 'Content-Type: application/json' -d'
{
"mappings": {
"axes_type_test12": {
"properties": {
"totalData": {
"type": "nested",
"properties": {
"gpsdt": {
"type": "date",
"format":"dateOptionalTime"
},
"extbatlevel": {
"type": "integer"
},
"intbatlevel" : {
"type" : "integer"
},
"lastgpsdt": {
"type": "date",
"format":"dateOptionalTime"
},
"satno" : {
"type" : "integer"
},
"srtangle" : {
"type" : "integer"
}
}
},
"imei": {
"type": "long"
},
"date": {
"type": "date", "format":"dateOptionalTime"
},
"id" : {
"type" : "long"
}
}
}
}
}'
And to append into existing array I call following API : -
Here is the documents which I have to append:-
data={
"script" : {"source": "ctx._source.totalData.add(params.count)",
"lang": "painless",
"params" : {"count" : { "gpsdt" : gpsdt,
"analog1" : analog1,
"analog2" : analog2,
"analog3" : analog3,
"analog4" : analog4,
"digital1" : digital1,
"digital2" : digital2,
"digital3" : digital3,
"digital4" : digital4,
"extbatlevel" : extbatlevel,
"intbatlevel" : intbatlevel,
"lastgpsdt" : lastgpsdt,
"latitude" : latitude,
"longitude" : longitude,
"odo" : odo,
"odometer" : odometer,
"satno" : satno,
"srtangle" : srtangle,
"speed" : speed
}
}
}
}
Document Parsing:-
json_data = json.dumps(data)
And API url is: -
API_ENDPOINT = "http://localhost:9200/axes_index_test12/axes_type_test12/"+str(documentId)+"/_update"
And Finnaly I call this API:-
headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
r = requests.post(url = API_ENDPOINT, data = json_data,headers=headers
Everything is fine with this but I am not getting good performance when I append new documents in existing array.
So please suggest me what changes I should make?
And I have 4 node cluster, 1 master, 2 data nodes and one cordinator node.