Multiple read requests with Firestore

[gabrielWilli]

I am using the Firestore library and I noticed something that may be exhibiting abnormal behavior. I have a check:

void setup() {
  Serial.begin(115200);
  dht.begin();
  initWifi();

  configTime(-3 * 3600, 0, "a.ntp.br", "b.ntp.br", "c.ntp.br");

  config.api_key = API_KEY;
  auth.user.email = USER_EMAIL;
  auth.user.password = USER_PASSWORD;

  config.token_status_callback = tokenStatusCallback;
  fbdo.setBSSLBufferSize(4096, 1024);
  fbdo.setResponseSize(2048);

  Firebase.begin(&config, &auth);

  myTimer.set(3600000);
  // 3600000

  temperature = dht.readTemperature();
  humidity = dht.readHumidity();

  if (!Firebase.Firestore.getDocument(&fbdo, FIREBASE_PROJECT_ID, "", DOCUMENT_PATH, FIELD_HUMIDITY) && !Firebase.Firestore.getDocument(&fbdo, FIREBASE_PROJECT_ID, "", DOCUMENT_PATH, FIELD_TEMPERATURE)) {
    Serial.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ");
    content.set("fields/humidity/mapValue/fields/value/doubleValue", humidity);
    content.set("fields/temperature/mapValue/fields/value/doubleValue", temperature);

    Firebase.Firestore.createDocument(&fbdo, FIREBASE_PROJECT_ID, "", DOCUMENT_PATH, content.raw());
    Serial.printf("New document created:\n%s\n\n", fbdo.payload().c_str());
  }
}

which is inside the setup method (where it should only be executed once), however, when I examine the Firestore metrics, I notice a significantly higher number of read requests than normal and expected, as described in the code.

Could you tell me if this is normal behavior or if it is something that requires attention?

[mobizt]

It depends on your usage.

As Firestore is not free and required paid plan, you cannot use it as condition or value checking.

The Firestore database is document based which involved the document (JSON) structured data when you read it from server.

The size of document can be small to large, depending on the complexity of your data.

Then every time you execute Firebase.Firestore.getDocumen, it involves few to tenths kilobytes of data to be transferred that cost your data usage bandwidth.

You can apply the field mask for returning only the fields you want.