How to calculate max in sth-comet? - fiware

Question

sth-comet offers the possibility of calculate max, min and other functions, as described [here]https://github.com/telefonicaid/fiware-sth-comet/blob/master/doc/manuals/aggregated-data-retrieval.md
But I have tried different types and it doesn't gives the aggregated result.
A simplified version of my entity (I use the attribute temperature in this example) is:
{
"id": "Beach:27",
"type": "Beach",
"flag": {
"type": "Property",
"value": "Verde"
},
"temperature": {
"type": "Number",
"value": 45
}
I have make this query that should give the maximum value:
http://{{sth-comet}}/STH/v1/contextEntities/type/Beach/id/Beach:27/attributes/temperature?aggrMethod=max&hLimit=100&hOffset=0
but the result is not the max but all the changes of the attribute:
{
"contextResponses": [
{
"contextElement": {
"attributes": [
{
"name": "temperature",
"values": [
{
"recvTime": "2019-09-15T18:32:18.166Z",
"attrType": "Number",
"attrValue": "43"
},
{
"recvTime": "2019-09-15T18:32:24.645Z",
"attrType": "Number",
"attrValue": "44"
},
{
"recvTime": "2019-09-15T18:32:28.931Z",
"attrType": "Number",
"attrValue": "45"
}
]
}
],
"id": "Beach:27",
"isPattern": false,
"type": "Beach"
},
"statusCode": {
"code": "200",
"reasonPhrase": "OK"
}
}
]
}
Which is the type that the property must have to work correctly? I tried "Number", "integer","string", "Property" but I don't obtain the "max" value.
Thank you for your time

Answer 1

The requests for aggregated time series context information can use the following query parameters:
aggrMethod: (mandatory) You can use max, min, sum and sum2.
aggrPeriod: (mandatory) you can use month, day, hour, minute and second.
dateFrom and dateTo: (optional) to range of data you query.
In your request you don't put the mandatory parameter (aggrPeriod). Can you test something else:
( http://{{sth-comet}}/STH/v1/contextEntities/type/Beach/id/Beach:27/attributes/temperature?aggrMethod=max&aggrPeriod=second&dateFrom=2019-09-15T00:00:00.000Z&dateTo=2019-09-15T23:59:59.999Z )
https://github.com/telefonicaid/fiware-sth-comet/blob/master/doc/manuals/aggregated-data-retrieval.md