Websocket connection warning

[gieljnssns]

Hi,

I recently realized an important Home Assistant limitation that may affect
EMHASS users relying on the websocket connection for historical data fitting.

For context: during the development and testing of the websocket-based history
retrieval, my Home Assistant instance still had the relevant data in
statistics_short_term. This meant 5-minute resolution data was still available
via the websocket API, so the approach worked as expected at the time.
I recently changed purge_keep_days: 360 -> purge_keep_days: 10 in HA and ran into issues.

If Home Assistant’s purge_keep_days is smaller than EMHASS’
historic_days_to_retrieve, the websocket API no longer returns high-resolution
(5-minute) state history. Instead, it falls back to long-term statistics with
~1 value per hour.

Key points:

• recorder purging removes high-resolution history
• websocket returns long-term statistics once raw data is gone
• long-term statistics are hourly aggregates
• this makes websocket-based fitting unsuitable for longer historical horizons

InfluxDB does not have this limitation and remains a reliable data source for
model fitting (I'm so happy I had an influx backup).

The websocket connection still makes sense for:

• MPC / real-time optimization
• short-term history windows
• potential future live sensor tracking

This is not a bug in EMHASS, but an HA architectural constraint that may be worth:

• documenting clearly
• warning about in the config
• or validating against purge_keep_days

Posting this mainly to prevent others from unknowingly relying on websocket
history for fitting over long periods.

[davidusb-geek]

Hi @gieljnssns, so maybe a big warning block in the documentation describing the point you raised might do it?

[davidusb-geek]

I just added a new section to the documentation presenting the Websocket option along with the warning message