Core: Creating wrong measuremets in InfluxDB depending on unit_of_measurement

[MarcEngrie]

The problem

using HASS .116.0 (updated yesterday) and Supervisor 247
Yesterday, I started to push data from Home Assistant into InfluxDB.
host: 192.168.1.42
port: 8086
username: !secret influxdb_username
password: !secret influxdb_password
database: homeassistant

include:
entities:
- sensor.weatherstation_outside_temperature
- sensor.weatherstation_outside_pressure
- sensor.weatherstation_outside_humidity
- sensor.greenhouse_temp_soil
- sensor.greenhouse_temp_outside
- sensor.greenhouse_temp_inside

Senosr data is coming from MQTT platform and initially the data was send with the unit of measurement included in the MQTT payload. Eg: 15°C, 80%, 1014hPa. The unit_of_measurement was mentioned in the sensor but set to "". The transfer to InfluxDB went OK, into measurements having the name of the entity mentioned above. But data was stored as a string/state and hence not useful to Grafana. I grasped and understand this. So far so good.
So I changed the MQTT transfer to be without the unit of measurement, only numeric data. changed the sensor so unit_of_measurement would be "°C" or "%" or "hPa". On the HA side all OK. However on the InfluxDB side, now measurements with the name °C, % and hPa are created and data is pushed in there but this time with field value and numeric data (so that is OK)
show measurements
name: measurements
name
%
hPa
sensor.greenhouse_temp_inside
sensor.greenhouse_temp_outside
sensor.weatherstation_outside_humidity
sensor.weatherstation_outside_pressure
sensor.weatherstation_outside_temperature
°C

To double-check behaviour, I commented out unit_of_measurement in the sensor and got then the data in the entity measurement with the value filed but then of course in HA you do not see the °C or % or hPa as unit appended to the value which is also not desirable.

• platform: mqtt
  unique_id: greenhouse_tempoutside
  name: "Greenhouse Temp Outside"
  state_topic: "greenhouses/greenhouse-DCA6323B6CF8/temp/outside"

  unit_of_measurement: "°C"

  device_class: temperature

• platform: mqtt
  unique_id: greenhouse_tempinside
  name: "Greenhouse Temp Inside"
  state_topic: "greenhouses/greenhouse-DCA6323B6CF8/temp/inside"

  unit_of_measurement: "°C"

  device_class: temperature

Is this normal behavior or a issue/bug?

Note: you should indicate in the documentation that when a database eg: homeassistant, is created, one should also create a retention policy for it as the preceding of the entity (in my case 'sensor') is taken as a retention policy in InfluxDB (1.8.2)

eg:
create database homeassistant
use homeassistant
create retention policy "sensor" on homeassistant duration 0s replication 1 default
show retention policies
name duration shardGroupDuration replicaN default
autogen 0s 168h0m0s 1 false
sensor 0s 168h0m0s 1 true

Environment

Running HA on Raspberry PI 4B 4 GB version 0.116.0 with supervisor 247.
InfluxDB : 1.8.2 on Windows 10 Update 2004

• Home Assistant Core release with the issue:

arch | armv7l
-- | --
chassis | embedded
dev | false
docker | true
docker_version | 19.03.11
hassio | true
host_os | HassOS 4.13
installation_type | Home Assistant OS
os_name | Linux
os_version | 4.19.127-v7l
python_version | 3.8.5
supervisor | 247
timezone | Europe/Brussels
version | 0.116.0
virtualenv | false

• Last working Home Assistant Core release (if known): not known
• Operating environment (OS/Container/Supervised/Core):
• Integration causing this issue:
• Link to integration documentation on our website:

Problem-relevant configuration.yaml

Traceback/Error logs

Additional information

[probot-home-assistant[bot]]

influxdb documentation
influxdb source
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[probot-home-assistant[bot]]

Hey there @fabaff, @mdegat01, mind taking a look at this issue as its been labeled with an integration (influxdb) you are listed as a codeowner for? Thanks!
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[MarcEngrie]

Hi, tested above with HassOS 4.16, HA 0.117.6 and Supervisor 2020.11.0 but issue remains.
Any idea when this will be looked at?
Thx
Marc

[mdegat01]

@MarcEngrie when adding data points to influxdb running v1.x.x the API requires that a measurement be provided with each data point. By default, the InfluxDB integration in HA uses the value in unit_of_measurement if it is present when recording a state change for an entity. If there is no unit_of_measurement for a given entity then it uses the ID of the entity instead. So what you are describing sounds like everything is working as expected using the default configuration for measurement.

Note that if you don't like this behavior you do have a number options available to you for changing it. measurement_attr can be set which changes the default behavior here so you can use entity ID instead of unit_of_measurement as the measurement field. You can also specify an override_measurement if you would prefer to store all data points in a single measurement.

Additionally you can also take more fine-grained control over this by using component_config, component_config_domain and component_config_glob to override the measurement used for specific entities or groups of entities. This is good if you generally like the default behavior but want to tweak it for some specific entities.

[MarcEngrie]

@mdegat01 Thx for this feedback. Somehow I did not grasp this default behavior. Now I understand it.
I implemented the suggested measurement_attr and this, indeed, solves my problem.
Thx a lot
Marc